MT9076AB [MITEL]

T1/E1/J1 3.3V Single Chip Transceiver; T1 / E1 / J1 3.3V单芯片收发器
MT9076AB
型号: MT9076AB
厂家: MITEL NETWORKS CORPORATION    MITEL NETWORKS CORPORATION
描述:

T1/E1/J1 3.3V Single Chip Transceiver
T1 / E1 / J1 3.3V单芯片收发器

文件: 总160页 (文件大小:413K)
中文:  中文翻译
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MT9076  
T1/E1/J1 3.3V Single Chip Transceiver  
Preliminary Information  
DS5289  
ISSUE 1  
January 2000  
Features  
Combined T1/E1/J1 framer and LIU, with PLL  
and 3 HDLCs  
Ordering Information  
MT9076AP  
MT9076AB  
68 Pin PLCC  
80 Pin LQFP  
-40 to +85°C  
In T1/J1 mode the LIU can recover signals  
attenuated by up to 43dB (7000ft of 22 AWG  
cable)  
In E1 mode the LIU can recover signals  
attenuated by up to 43dB (2200m of 0.65mm  
cable)  
Description  
The MT9076 is a highly featured single chip solution  
for terminating T1/E1/J1 trunks. It contains a long-  
haul LIU, an advanced framer, a high performance  
PLL, and 3 HDLCs.  
Low jitter digital PLL (intrinsic jitter < 0.02UI)  
HDLCs can be assigned to any timeslot  
Comprehensive alarm detection, performance  
monitoring and error insertion functions  
In T1 mode, the MT9076 supports D4, ESF and  
SLC-96 formats meeting the latest recommendations  
including AT&T PUB43801, TR-62411; ANSI T1.102,  
T1.403 and T1.408; Telcordia GR-303-CORE.  
2.048Mbit/s or 8.192Mbit/s ST-BUS streams  
Support for Inverse Mux for ATM (IMA)  
Support for V5.1 and V5.2 Access Networks  
3.3V operation with 5V tolerant inputs  
In E1 mode, the MT9076 supports the latest ITU-T  
Recommendations including G.703, G.704, G.706,  
G.732, G.775, G.796, G.823, G.964 (V5.1), G.965  
(V5.2) and I.431. It also supports ETSI ETS 300 011,  
ETS 300 166, ETS 300 233, ETS 300 324 (V5.1) and  
ETS 300 347 (V5.2).  
Intel or Motorola non-multiplexed 8-bit  
microprocessor port  
JTAG boundary scan  
Applications  
E1/T1 add/drop multiplexers  
Access networks  
Primary rate ISDN nodes  
Digital Cross-connect Systems (DCS)  
TxDL TxDLCLK  
TxMF  
TxAO TxB TxA  
DSTi  
CSTi  
ST-BUS  
Interface  
Transmit Framing, Error,  
Test Signal Generation and Slip Buffer  
TTIP  
TRING  
Line  
Driver  
Tdi  
Tdo  
PL Loop  
Tms  
Tclk  
Trst  
ST Loop  
National  
Bit Buffer  
S/FR  
Jitter Attenuator  
& Clock Control  
IRQ  
BS/LS  
OSC1  
OSC2  
D7~D0  
Data Link,  
CAS  
AC4  
AC0  
R/W/WR  
CS  
HDLC0  
HDLC1  
Buffer  
DG Loop  
RTIP  
RRING  
DS/RD  
DSTo  
CSTo  
Receive Framing, Performance Monitoring,  
Alarm Detection, 2 Frame Slip Buffer  
ST-BUS  
Interface  
RxDLCLK RxDL  
RxMF/TxFP  
LOS  
RxFP  
Exclk F0b C4b  
Figure 1 - MT9076 Functional Block  
1
MT9076  
Preliminary Information  
8
6
4
2
68 66 64 62  
CS  
RESET  
IRQ  
60  
58  
56  
54  
52  
50  
48  
46  
44  
10  
12  
14  
16  
18  
20  
22  
24  
26  
TxAO  
Trst  
Tclk  
Tms  
Tdo  
Tdi  
GNDATX  
TRING  
TTIP  
VDDATX  
VDD2  
VSS2  
IC1  
RxFP  
F0b  
C4b  
D0  
D1  
D2  
D3  
VSS5  
IC4  
INT/MOT  
VDD5  
D4  
68 PIN PLCC  
D5  
D6  
D7  
R/W/WR  
AC0  
Exclk  
28 30 32 34 36 38 40 42  
60 58 56 54 52 50 48 46 44 42  
62  
40  
NC  
NC  
TxAO  
Trst  
Tclk  
Tms  
Tdo  
Tdi  
GNDATX  
TRING  
TTIP  
VDDATX  
VDD2  
VSS2  
IC1  
RxFP  
F0b  
C4b  
NC  
NC  
CS  
38  
36  
64  
66  
68  
70  
72  
74  
76  
78  
80  
RESET  
IRQ  
D0  
D1  
D2  
D3  
34  
32  
80 PIN LQFP  
VSS5  
IC4  
INT/MOT  
VDD5  
D4  
30  
28  
26  
24  
22  
D5  
D6  
D7  
R/W/WR  
AC0  
NC  
Exclk  
NC  
2
4
6
8
10 12 14  
16 18  
20  
Figure 2 - Pin Connections  
2
Preliminary Information  
MT9076  
Pin Description  
Pin #  
Name  
Description  
PLCC LQFP  
1
51  
OSC1 Oscillator (3V Input). This pin is either connected via a 20.000 MHz crystal to OSC2  
where a crystal is used, or is directly driven when a 20.000 MHz. oscillator is employed.  
2
52  
OSC2 Oscillator (3V Output). Connect a 20.0 MHz crystal between OSC1 and OSC2. Not  
suitable for driving other devices.  
3
4
5
53  
54  
55  
V
Negative Power Supply . Digital ground.  
SS4  
V
Positive Power Supply . Digital supply (+3.3V ± 5%).  
DD4  
CSTo  
Control ST-BUS (5V tolerant Output). CSTo carries serial streams for CAS and CCS  
respectively a 2.048 Mbit/s ST-BUS status stream which contains the 30 receive  
signaling nibbles (ABCDZZZZ or ZZZZABCD). The most significant nibbles of each ST-  
BUS time slot are valid and the least significant nibbles of each ST-BUS time slot are  
tristated when control bit MSN (page 01H, address 1AH, bit 1) is set to 1. If MSN=0, the  
position of the valid and tristated nibbles are reversed.  
6
56  
CSTi  
Control ST-BUS (5V tolerant Input). CSTi carries serial streams for CAS and CCS  
respectively a 2.048 Mbit/s ST-BUS control stream which contains the 30 transmit  
signaling nibbles (ABCDXXXX or XXXXABCD) when RPSIG=0. When RPSIG=1 this  
pin has no function. The most significant nibbles of each ST-BUS time slot are valid and  
the least significant nibbles of each ST-BUS time slot are ignored when control bit MSN  
(page 01H, address 1AH, bit 1) is set to 1. If MSN=0, the position of the valid and  
ignored nibbles is reversed.  
7
8
57  
58  
DSTo  
DSTi  
Data ST-BUS (5V tolerant Output). A 2.048 Mbit/s serial stream which contains the  
24/30 PCM(T1/E1) or data channels received on the PCM 24/30 (T1/E1) line.  
Data ST-BUS (5V tolerant Input). A 2.048 Mbit/s serial stream which contains the  
24/30 (T1/E1) PCM or data channels to be transmitted on the PCM 24/30 (T1/E1)  
line.  
9
59  
DS/RD Data/Read Strobe (5V tolerant Input).  
In Motorola mode (DS), this input is the active low data strobe of the processor  
interface. In Intel mode (RD), this input is the active low read strobe of the processor  
interface.  
10  
11  
63  
64  
CS  
Chip Select (5V tolerant Input). This active low input enables the non-multiplexed  
parallel microprocessor interface of the MT9076. When CS is set to high, the  
microprocessor interface is idle and all bus I/O pins will be in a high impedance state.  
RESET RESET (5V tolerant Input). This active low input puts the MT9076 in a reset condition.  
RESET should be set to high for normal operation. The MT9076 should be reset after  
power-up. The RESET pin must be held low for a minimum of 1µsec. to reset the device  
properly.  
12  
65  
IRQ  
Interrupt Request (5V tolerant Output). A low on this output pin indicates that an  
interrupt request is presented. IRQ is an open drain output that should be connected to  
VDD through a pull-up resistor. An active low CS signal is not required for this pin to  
function.  
13 - 66-69 D0 - D3 Data 0 to Data 3 (5V tolerant Three-state I/O). These signals combined with D4-D7  
16  
form the bidirectional data bus of the parallel processor interface (D0 is the least  
significant bit).  
17  
18  
70  
71  
VSS5 Negative Power Supply. Digital ground.  
IC4  
Internal Connection (3V Input). Tie to V (Ground) for normal operation.  
SS  
3
MT9076  
Preliminary Information  
Pin Description (continued)  
Pin #  
Name  
Description  
PLCC LQFP  
19  
72  
INT/MOT Intel/Motorola Mode Selection (5V tolerant Input). A high on this pin configures the  
processor interface for the Intel parallel non-multiplexed bus type. A low configures the  
processor interface for the Motorola parallel non-multiplexed type.  
20  
73  
VDD5 Positive Power Supply. Digital supply (+3.3V ± 5%).  
21 - 74-77 D4 - D7 Data 4 to Data 7 (5V tolerant Three-state I/O). These signals combined with D0-D3  
24  
form the bidirectional data bus of the parallel processor interface (D7 is the most  
significant bit).  
25  
78  
R/W/WR Read/Write/Write Strobe (5V tolerant Input). In Motorola mode (R/W), this input  
controls the direction of the data bus D[0:7] during a microprocessor access. When R/W  
is high, the parallel processor is reading data from the MT9076. When low, the parallel  
processor is writing data to the MT9076. For Intel mode (WR), this active low write  
strobe configures the data bus lines as output.  
26 -  
30  
79, AC0 - AC4 Address/Control 0 to 4 (5V tolerant Inputs). Address and control inputs for the  
2-5  
non-multiplexed parallel processor interface. AC0 is the least significant input.  
31  
6
GNDARx Receive Analog Ground. Analog ground for the LIU receiver.  
32  
33  
7
8
RTIP  
Receive TIP and RING (3V Input). Differential inputs for the receive line signal - must  
RRING be transformer coupled (See Figure 6). In digital framer mode these pins accept digital  
3 volt signals from a physical layer device. They may accept a split phase unipolar  
signal (RTIP and RRING employed) or an NRZ signal (RTIP only used).  
34  
35  
36  
37  
9
VDDARx Receive Analog Power Supply. Analog supply for the LIU receiver (+3.3V ± 5%).  
VDD1 Positive Power Supply. Digital supply (+3.3V ± 5%).  
10  
11  
12  
VSS1 Negative Power Supply. Digital ground.  
TxA  
Transmit A (5V tolerant Output). When the internal LIU is disabled (digital framer  
only mode), if control bit NRZ=1, an NRZ output data is clocked out on pin TxA with the  
rising edge of Exclk (TxB has no function when NRZ format is selected). If NRZ=0, pins  
TxA and TxB are a complementary pair of signals that output digital dual-rail data  
clocked out with the rising edge of Exclk.  
38  
39  
13  
TxB  
Transmit B (5V tolerant Output). When the internal LIU is disabled and control bit  
NRZ=0, pins TxA and TxB are a complementary pair of signals that output digital dual-  
rail data clocked out with the rising edge of Exclk.  
14 RxDLCLK Data Link Clock (5V tolerant Output). A gapped clock signal derived from the  
extracted line clock, available for an external device to clock in RxDL data (at 4, 8, 12,  
16 or 20 kHz) on the rising edge.  
40  
41  
15  
RxDL  
Receive Data Link (5V tolerant Output). A serial bit stream containing received line  
data after zero code suppression. This data is clocked out with the rising edge of Exclk.  
16  
TxMF Transmit Multiframe Boundary (5V tolerant Input). An active low input used to set  
the transmit multiframe boundary (CAS or CRC multiframe). The MT9076 will generate  
its own multiframe if this pin is held high. This input is usually pulled high for most  
applications.  
4
Preliminary Information  
MT9076  
Pin Description (continued)  
Pin #  
Name  
Description  
PLCC LQFP  
42  
17  
RxMF/ Receive Multiframe Boundary / Transmit Frame Boundary (5V tolerant Output). If  
TxFP  
the control bit Tx8KEN (page 02H address 10H bit 2) is low, this negative output pulse  
delimits the received multiframe boundary. The next frame output on the data stream  
(DSTo) is basic frame zero on the T1 or PCM 30 link. In E1 mode this receive  
multiframe signal can be related to either the receive CRC multiframe (page 01H,  
address 17H, bit 6, MFSEL=1) or the receive signaling multiframe (MFSEL=0). If the  
control bit Tx8KEN is set high, this positive output pulse delimits the frame boundary  
(the first bit transmit in the frame) for the digital output stream on pins TXA and TXB.  
43  
44  
18  
22  
BS/LS Bus/Line Syncronization Mode Selection (5V tolerant Input). If high, C4b and F0b  
will be inputs; if low, C4b and F0b will be outputs.  
Exclk  
C4b  
2.048 MHz in E1 mode or 1.544MHz in T1 mode, Extracted Clock (5V tolerant  
Output). The clock extracted from the received signal and used internally to clock in  
data received on RTIP and RRING.  
45  
46  
23  
24  
4.096 MHz System Clock (5V tolerant Input/Output). C4b is the clock for the ST-BUS  
sections and transmit serial PCM data of the MT9076. In the free-run (S/FR/Exclki=0) or  
line synchronous mode (S/FR/Exclki=1 and BS/LS=0) this signal is an output, while in  
bus synchronous mode (S/FR/Exclki=1 and BS/LS=1) this signal is an input clock.  
F0b  
Frame Pulse (5V tolerant Input/Output). This is the ST-BUS frame synchronization  
signal, which delimits the 32 channel frame of CSTi, CSTo, DSTi, DSTo and the  
PCM30 link. In the free-run (S/FR/Exclki=0) or line synchronous mode (S/FR/Exclki=1  
and BS/LS=0) this signal is an output, while in bus synchronous mode (S/FR/Exclki=1  
and BS/LS=1) this signal is an input.  
47  
25  
RxFP  
IC1  
Receive Frame Pulse/Receive CCS Clock (5V tolerant Output). An 8kHz pulse  
signal, which is low for one extracted clock period. This signal is synchronized to the  
receive DS1 or PCM 30 basic frame boundary.  
48  
49  
50  
51  
26  
27  
28  
29  
Internal Connection. Must be left open for normal operation.  
Negative Power Supply. Digital ground.  
V
SS2  
DD2  
V
Positive Power Supply. Digital supply (+3.3V ± 5%).  
VDD  
Transmit Analog Power Supply. Analog supply for the LIU transmitter (+3.3V ±5%).  
ATx  
52  
53  
30  
31  
TTIP  
Transmit TIP and RING(Output). Differential outputs for the transmit line signal - must  
TRING be transformer coupled (See Figure 6).  
54  
55  
56  
32  
33  
34  
GND  
Transmit Analog Ground . Analog ground for the LIU transmitter.  
ATx  
Tdi  
IEEE 1149.1a Test Data Input (3V Input). If not used, this pin should be pulled high.  
Tdo  
IEEE 1149.1a Test Data Output (5V tolerant Output). If not used, this pin should be  
left unconnected.  
57  
35  
Tms  
IEEE 1149.1a Test Mode Selection (3V Input). If not used, this pin should be pulled  
high.  
58  
59  
60  
36  
37  
38  
Tclk  
Trst  
IEEE 1149.1a Test Clock Signal (3V Input). If not used, this pin should be pulled high.  
IEEE 1149.1a Reset Signal (3V Input). If not used, this pin should be held low.  
TxAO  
Transmit All Ones (Input). High - TTIP, TRING will transmit data normally. Low - TTIP,  
TRING will transmit an all ones signal.  
5
MT9076  
Preliminary Information  
Pin Description (continued)  
Pin #  
Name  
Description  
PLCC LQFP  
61  
43  
LOS  
Loss of Signal or Synchronization (5V tolerant Output). When high, and LOS/LOF  
(page 01H address 19H bit 0) is zero, this signal indicates that the receive portion of the  
MT9076 is either not detecting an incoming signal (bit LLOS on page 03H address 16H  
is one) or is detecting a loss of basic frame alignment condition (bit TSYNC (T1), SYNC  
(E1) on page 03H address 10H is one). If LOS/LOF=1, a high on this pin indicates a  
loss of signal condition.  
62  
63  
64  
44  
45  
IC2  
IC3  
Internal Connection (3V Input). Tie to V (Ground) for normal operation.  
SS  
Internal Connection (3V Input). Tie to V (Ground) for normal operation.  
SS  
46 TxDLCLK Transmit Data Link Clock (5V tolerant Output). A gapped clock signal derived from a  
gated 2.048 Mbit/s clock for transmit data link at 4, 8, 12, 16 or 20 kHz. The transmit  
data link data (TxDL) is clocked in on the rising edge of TxDLCLK. TxDLCLK can also  
be used to clock DL data out of an external serial controller.  
65  
66  
47  
TxDL  
Transmit Data Link (5V tolerant Input). An input serial stream of transmit data link  
data at 4, 8, 12, 16 or 20 kbit/s.  
48  
S/FR/ Synchronization/ Freerun / Extracted Clock (5V tolerant Input). If low, and the  
Exclki internal LIU is enabled, the MT9076 is in free run mode. Pins 45 C4b and 46 F0b are  
outputs generating sytem clocks. Slips will occur in the receive slip buffer as a result of  
any deviation between the MT9076's internal PLL (which is free - running) and the  
frequency of the incoming line data. If high, and the internal LIU is enabled, the MT9076  
is in Bus or Line Synchronization mode depending on the BS/LS pin. If the internal LIU  
is disabled, in digital framer mode, this pin (Exclki) takes an input clock 1.544Mhz (T1) /  
2.048Mhz (E1) that clocks in the received digital data on pins RXA and RXB with its  
rising edge.  
67  
68  
49  
50  
VDD3 Positive Power Supply. Digital supply (+3.3V ± 5%).  
VSS3 Negative Power Supply. Digital ground.  
Device Overview  
The MT9076 is a T1/E1/J1 single chip transceiver that incorporates an advanced framer, a long-haul LIU (Line  
Interface Unit), a low jitter PLL (Phase Locked Loop) and 3 HDLCs (High-level Data Link Controller). The T1,  
E1 and J1 operating modes are selectable under software control.  
Standards Compliance  
In T1 mode, the MT9076 meets or supports the latest recommendations including Telcordia GR-303-CORE,  
AT&T PUB43801, TR-62411, ANSI T1.102, T1.403 and T1.408. In T1 ESF mode the CRC-6 calculation and  
yellow alarm can be configured to meet the requirements of a J1 interface.  
In E1 mode, the MT9076 meets or supports the latest ITU-T Recommendations for PCM 30 and ISDN primary  
rate including G.703, G.704, G.706, G.732, G.775, G.796, G.823, G.964 (V5.1), G.965 (V5,2) and I.431. It also  
meets or supports ETSI ETS 300 011, ETS 300 166, ETS 300 233, ETS 300 324 (V5.1) and ETS 300 347  
(V5.2).  
Microprocessor Port  
The MT9076 registers are accessible via an 8-bit parallel Motorola or Intel non-multiplexed microprocessor  
interface.  
6
Preliminary Information  
MT9076  
LIU  
The MT9076 LIU interfaces the digital framer functions to either the DS1 (T1 mode) or PCM 30 (E1 mode)  
transformer-isolated four wire line.  
In T1 mode, the LIU can pre-equalize the transmit signal to meet the T1.403 and T1.102 pulse templates after  
attenuation by 0 - 655 feet of 22 AWG PIC cable, alternatively it can provide line build outs of 7.5dB, 15dB and  
22.5dB. In T1 mode the receiver can recover signals attenuated by up to 43dB at 772kHz.  
In E1 mode, the LIU transmits signals that meet the G.703 2.048 Mbit/s pulse template and the receiver can  
recover signals attenuated by up to 43dB at 1024kHz.  
Digitial Framer Only Mode  
To accommodate some special applications, the MT9076 supports a digital framer only mode that provides  
direct access to the transmit and receive data in digital format, i.e. by-passing the analog LIU front-end. In  
digital framer only mode, the MT9076 supports unipolar non-return to zero or bipolar return to zero data.  
PLL and Slip Buffers  
The MT9076 PLL attenuates jitter from 2.5 Hz with a roll-off of 20 dB/decade. The intrinsic jitter is less than  
0.02 UI. The device can operate in one of three timing modes: System Bus Synchronous Mode, Line  
Synchronous Mode, or Free-run Mode. In all three timing modes the low jitter output of the PLL provides timing  
to the transmit side of the LIU.  
In T1 mode, the receive and transmit paths both include two-frame slip buffers. The transmit slip buffer features  
programmable delay and serves as a Jitter Attenuator (JA) FIFO and a rate converter between the ST-BUS and  
the 1.544 Mbit/s T1 line rate.  
In E1 mode, the receive path includes a two-frame slip buffer and the transmit path contains a 128 bit Jitter  
Attenuator (JA) FIFO with programmable depth.  
Interface to the System Backplane  
On the system side the MT9076 framers can interface to a 2.048Mbit/s or 8.192Mbit/s ST-BUS backplane.  
There is an asynchronous mode for Inverse MUX for ATM (IMA) applications, this enables the framer to  
interface to a 1.544Mbit/s (T1) or 2.048Mbit/s (E1) serial bus with asynchronous transmit and receive timing.  
Framing Modes  
The MT9076 framers operate in termination mode or transparent mode. In the receive transparent mode, the  
received line data is channelled to the DSTo pin with arbitrary frame alignment. In the transmit transparent  
mode, no framing or signaling is imposed on the data transmitted from the DSTi pin onto the line.  
In T1 mode, the framers operate in any of the following framing modes: D4, Extended Superframe (ESF) or  
SLC-96.  
In E1 mode, the framers run three framing algorithms: basic frame alignment, signaling multiframe alignment  
and CRC-4 multiframe alignment. The Remote Alarm Indication (RAI) bit is automatically controlled by an  
internal state machine.  
7
MT9076  
Preliminary Information  
Access to the Maintenance Channel  
The T1 ESF Facility Data Link (FDL) bits can be accessed in the following three ways: Through the data link  
pins TxDL, RxDL, RxDLC and TxDLC; through internal registers for Bit Oriented Messages; through an  
embedded HDLC.  
In E1 mode, the Sa bits (bits 4-8 of the non-frame alignment signal) can be accessed in four ways: Through  
data link pins TxDL, RxDL, RxDLC and TxDLC, through single byte transmit and receive registers; through five  
byte transmit and receive national bit buffers; through an embedded HDLC.  
Robbed Bit Signaling/Channel Associated Signaling  
Robbed bit signaling and channel associated signaling information can be accessed two ways: Via the  
microport; via the CSTi and CSTo pins. Signaling information is frozen upon loss of multiframe alignment.  
In T1 mode, the MT9076 supports AB and ABCD robbed bit signaling. Robbed bit signaling can be enabled on  
a channel by channel basis.  
In E1 mode the MT9076 supports Channel Associated Signaling (CAS) multiframing.  
HDLCs  
The MT9076 provides three embedded HDLCs with 128 byte deep transmit and receive FIFOs.  
In T1 mode, the embedded HDLCs can be assigned to any channel and can operate at 56 kbit/s or 64 kbit/s. In  
T1 ESF mode, HDLCO can be assigned to the 4 kbit/s FDL.  
In E1 mode, the embedded HDLCs can be assigned to any timeslot and can operate at 64kbit/s. HDLCO can  
be assigned to timeslot 0 Sa bits (bits 4-8 of the non-frame alignment signal) and can operate at 4,8,12,16 or  
20kbit/s.  
Performance Monitoring and Debugging  
The MT9076 has a comprehensive suite of performance monitoring and debugging features. These include  
15  
error counters, loopbacks, deliberate error insertion and a 2 –1 QRS/PRBS generator/detector.  
Interrupts  
The MT9076 provides a comprehensive set of maskable interrupts. Interrupt sources consist of  
synchronization status, alarm status, counter indication and overflow, timer status, slip indication, maintenance  
functions and receive signaling bit changes.  
8
Preliminary Information  
MT9076  
MT9076 Detailed Feature List  
Standards Compliance and Support  
T1/J1 Mode  
E1 Mode  
ANSI:  
ETSI:  
T1.102,T1.231, T1.403, T1.408  
ETS 300 011, ETS 300 166, ETS 300 233,  
ETS 300 324, ETS 300 347  
AT&T:  
TR 62411, PUB43801  
ITU:  
G.703, G.704, G.706, G.732 G.775,  
G.796, G.823, I.431, G.964, G.965  
Telcordia:  
GR-303-CORE  
TTC:  
JT-G703, JT-G704, JT-G706  
Line Interface Unit (LIU)  
T1 and E1 modes use the same 1:2.4 transmit and receive transformers  
Internal register allows termination imepedance to be changed under software control.  
Programmable pulse shapes and pulse amplitudes  
Automatic or manual receiver equalization  
Receive signal peak amplitude is reported with 8-bit resolution  
Output pin to indicate Loss Of Signal/ Loss Of Frame synchronization  
LIU output is disabled at power-up until enabled by software  
Input pin to force transmission of AIS  
T1/J1 Mode  
E1 Mode  
Reliably recovers signals with cable  
attenuation up to 43dB @ 772 kHz  
Reliably recovers signals with cable  
attenuation up to 43 dB @ 1024 kHz  
Transmit pulse meets T1.403 and T1.102  
pulse templates  
Transmit pulse meets G.703 pulse template  
Indicates analog Los Of Signal if the received  
signal is more than 20 dB or 40dB below  
nominal for more than 1ms  
Indicates analog Los Of Signal if the received  
signal is more than 20dB or 40dB below  
nominal for more than 1ms  
Receiver tolerates jitter as required by AT&T  
TR62411  
Receiver tolerates jitter as required by ETSI  
ETS 300 011  
Transmit Pre-equalization and Line Build Out  
options:  
0-133 feet  
133-266 feet  
266-399 feet  
399-533 feet  
533-655 feet  
-7.5dB  
-15dB  
-22.5dB  
9
MT9076  
Preliminary Information  
Digital Framer Mode  
The LIU can be disabled and bypassed to allow the MT9076 to be used as a digital framer  
Single phase NRZ or two phase NRZ modes are software selectable  
Line coding is software selectable  
Phase Lock Loop  
Locks to a 4.096 MHz input clock, or to the 1.544MHz / 2.048MHz extracted clock  
IMA mode locks to 1,544MHz or 2,048MHz external clock  
Attenuates jitter from less than 2.5 Hz with a roll off of 20 dB/decade  
Attenuates jitter in the transmit or receive direction  
Intrinsic jitter less than 0.02 UI  
Meets the jitter characteristics as specified in AT&T TR62411  
Meets the jitter characteristics as specified in ETS 300 011  
Can be operated in Free-run, Line Synchronous or System Bus Synchronous modes  
Access and Control  
MT9076 registers can be accessed via an 8-bit non-multiplexed parallel microprocessor port  
The parallel port can be configured for Motorola or Intel style control signals  
Backplane Interfaces  
2.048Mbit/s or 8.192Mbit/s ST-BUS  
IMA mode, 1.544Mbit/s (T1) or 2.048Mbit/s (E1) serial bus with asynchronous transmit and receive  
timing for Inverse MUX for ATM (IMA) applications. Slip buffers are bypassed and signaling is disabled.  
CSTo/CSTi pins can be used to access the receive/transmit signaling data  
RxDL pin can be used to access the entire B8ZS/HDB3 decoded receive stream including framing bits  
TxDL pin can be used to transmit data on the FDL (T1) or the Sa bits (E1)  
T1/J1 Mode  
E1 Mode  
PCM-24 channels 1-24 are mapped to ST-  
BUS channels 0-23 respectively  
PCM-30 timeslots 0-31 are mapped to ST-  
BUS channels 0-31 respectively  
The framing-bit is mapped to ST-BUS  
channel 31  
10  
Preliminary Information  
MT9076  
Data Link  
T1/J1 Mode  
E1 Mode  
Three methods are provided to access the  
datalink:  
Two methods are provided to access the  
datalink:  
1. TxDL and RxDL pins support transmit and  
receive datalinks  
1. TxDL and RxDL pins support transmit and  
receive datalinks over the Sa4~Sa8 bits  
2. Bit Oriented Messages are supported via  
internal registers  
2. An internal HDLC can be assigned to transmit/  
receive data via the Sa4~Sa8 bits  
3. An internal HDLC can be assigned to transmit/  
receive over the FDL in ESF mode  
In transparent mode, if the Sa4 bit is used for  
an intermediate datalink, the CRC-4  
remainder can be updated to reflect changes  
to the Sa4 bit  
Access and Monitoring for National (Sa) Bits (E1 mode only)  
In addition to the datalink functions, the Sa bits can be accessed using:  
Single byte register  
Five byte transmit and receive national bit buffers  
A maskable interrupt is generated on the change of state of any Sa bit  
Three Embedded Floating HDLCs (HDLC0, HDLC1, HDLC2)  
Successive writes/reads can be made to the transmit/receive FIFOs at 160 ns or 80ns intervals  
Flag generation and Frame Check Sequence (FCS) generation and detection, zero insertion and  
deletion  
Continuous flags, or continuous 1s are transmitted between frames  
Transmit frame-abort  
Transmit end-of-packet after a programmable number of bytes (up to 65,536 bytes)  
Invalid frame handling:  
Frames yielding an incorrect FCS are tagged as bad packets  
Frames with fewer than 25 bits are ignored  
Frames with fewer than 32 bits between flags are tagged as bad packets  
Frames interrupted by a Frame-Abort sequence remain in the FIFO and an interrupt is generated  
Access is provided to the receive FCS  
FCS generation can be inhibited for terminal adaptation  
Recognizes single byte, dual byte and all call addresses  
Independent, 16-128 byte deep transmit and receive FIFOs  
Receive FIFO maskable interrupts for near full (programmable levels) and overflow conditions  
Transmit FIFO maskable interrupts for nearly empty (programmable levels) and underflow conditions  
Maskable interrupts for transmit end-of-packet and receive end-of-packet  
Maskable interrupts for receive bad-frame (includes frame abort)  
Transmit-to-receive and receive-to-transmit loopbacks are provided  
Transmit and receive bit rates and enables are independent  
Frame aborts can be sent under software control and they are automatically transmitted in the event of  
a transmit FIFO underrun  
11  
MT9076  
Preliminary Information  
T1/J1 Mode  
E1 Mode  
HDLC0  
HDLC0  
Assignable to the ESF Facility Data Link or  
any channel  
Assigned to timeslot-0, bits Sa4~Sa8 or any  
other timeslot  
Operates at 4 kbps, 56 kbps or 64 kbps  
Operates at 4, 8, 12, 16 or 20 kbps  
depending on which Sa bits are selected for  
HDLC0 use  
HDLC1, HDLC2  
Assignable to any channel  
HDLC1, HDLC  
Operates at 56 kbps or 64 kbps  
Assigned to any timeslot except timeslot-0  
Operates at 64 kbps  
Slip Buffers  
T1/J1 Mode  
Transmit Slip Buffer  
E1 Mode  
Receive Slip Buffer  
Two-frame slip buffer capable of performing a  
controlled slip  
Two-frame slip buffer capable of performing a  
controlled slip  
Intended for rate conversion and jitter  
attenuation in the transmit direction  
Wander tolerance of 208 UI peak-to-peak  
Programmable delay  
Indication of slip direction  
Transmit slips are independent of receive  
slips  
Indication of slip direction  
Receive Slip Buffer  
Two-frame slip buffer capable of performing a  
controlled slip  
Wander tolerance of 142 UI (92 µs) peak  
Indication of slip direction  
Jitter Attenuator FIFO  
A jitter attenuator FIFO is available on the transmit side in E1 mode and in IMA mode. The depth of the  
JA FIFO can be configured to be from16 bits deep to 128 bits deep in 16 bit increments  
Inverse Mux for ATM (IMA) Mode  
T1/J1 Mode  
E1 Mode  
Transmit and receive datastreams are  
independently timed  
Transmit and receive datastreams are  
independently timed  
The transmit clock synchronizes to a  
1,544MHz clock  
Receive slip buffer is bypassed  
CAS and HDLCs are disabled  
Transmit and receive slip buffers are  
bypassed  
Robbed bit signaling and HDLCs are disabled  
12  
Preliminary Information  
MT9076  
Framing Algorithm  
T1/J1 Mode  
E1 Mode  
Synchronizes with D4 or ESF protocols  
Supports SLC-96 framing  
MT9076 contains 3 distinct and independent  
framing algorithms  
1. Basic frame alignment  
Framing circuit is off-line  
2. Signaling multiframe alignment  
3. CRC-4 multiframe alignment  
Transparent transmit and receive modes  
Transparent transmit and receive modes  
In D4 mode the Fs bits can optionally be  
cross checked with the Ft bits  
Automatic interworking between interfaces  
with and without CRC-4 processing  
capabilities is supported  
The start of the ESF multiframe can be  
determined by the following methods:  
Free-run  
An automatic reframe is forced if 3  
consecutive frame alignment patterns or  
three consecutive non-frame alignment bits  
are received in error  
Software reset  
Synchronized to the incoming multiframe  
An automatic reframe is initiated if the  
framing bit error density exceeds the  
programmed threshold  
In transparent mode, no reframing is forced  
by the device  
In transparent mode, no reframing is forced  
by the device  
Software can force a reframe at any time  
Software can force a multiframe reframe at  
any time  
Software can force a reframe at any time  
In ESF mode the CRC-6 bits can be  
optionally confirmed before forcing a new  
frame alignment  
E-bits can optionally be set to zero until CRC  
synchronization is achieved  
Optional automatic RAI  
During a reframe the signaling bits are frozen  
and error counting for Ft, Fs, ESF framing  
pattern and CRC-6 bits is suspended  
Supports CAS multiframing  
Optional automatic Y-bit to indicate CAS  
multiframe alignment  
If J1 CRC-6 is selected the Fs bits are  
included in the CRC-6 calculation  
J1 CRC-6 and J1 Yellow Alarm can be  
independently selected  
Supports robbed bit signaling  
Line Coding  
T1/J1 Mode  
E1 Mode  
B8ZS or AMI line coding  
Pulse density enforcement  
Forced ones insertion  
HDB3 or AMI line coding  
13  
MT9076  
Preliminary Information  
Channel Associated Signaling  
ABCD or AB bits can be automatically inserted and extracted  
Transmit ABCD or AB bits can be passed via the microport or via the CSTi pin  
Receive ABCD or AB bits are accessible via the microport or via the CSTo pin  
Most significant or least significant CSTi/CSTo nibbles can be selected to carry signaling bits  
Unused nibble positions in the CSTi/CSTo bandwidth are tri-stated  
An interrupt is provided in the event of changes in any of the signaling bits  
Receive signaling bits are frozen if signaling multiframe alignment is lost  
T1/J1 Mode  
E1 Mode  
Signaling bits can be debounced by 6 ms  
Signaling bits can be debounced by14 ms  
Alarms  
T1/J1 Mode  
E1 Mode  
D4 Yellow Alarm, two types  
Remote Alarm Indication (RAI)  
• Bit 3 of the receive NFAS  
1. Bit position 2 is zero for virtually every DS0  
over 48ms  
2. Two consecutive ones in the S-bit position of  
the twelfth frame  
Alarm Indication Signal (AIS)  
Unframed all ones signal for at least a double  
frame or two double frames  
ESF Yellow Alarm, two types  
1. Reception of 0000000011111111 in seven  
or more codewords out of ten (T1)  
Timeslot 16 Alarm Indication Signal  
All ones signal in timeslot 16  
2. Reception of 1111111111111111 in seven  
or more codewords out of ten (J1)  
Loss Of Signal (LOS)  
Alarm Indication Signal (AIS)  
Analog Loss Of Signal is declared if the  
received signal is more than 20 dB or 40 dB  
below nominal for at least 1 ms  
Declared if fewer than six zeros are detected  
during a 3 ms interval  
Digital Loss Of Signal is declared if 192 or 32  
consecutive zeros are received  
Loss Of Signal (LOS)  
Analog Loss Of Signal is declared if the  
received signal is more than 20 dB or 40 dB  
below nominal for at least 1 ms  
Output pin indicates LOS and/or loss of  
frame alignment  
Remote Signaling Multiframe Alarm  
Y-bit of the multiframe alignment signal  
Digital Loss Of Signal is declared if 192 or 32  
consecutive zeros are received  
Output pin indicates LOS and/or loss of  
frame alignment  
14  
Preliminary Information  
MT9076  
Maskable Interrupts  
T1/J1 Mode  
E1 Mode  
HDLC Interrupts  
Change of state of terminal  
synchronization  
Change of state of basic  
frame alignment  
Go ahead pattern received  
End of packet received  
End of packet transmitted  
Change of state of multiframe  
synchronization  
Change of state of multiframe  
synchronization  
End of packet read from  
receive FIFO  
Change of received bit  
oriented message  
Change of state of CRC-4  
multiframe synchronization  
Transmit FIFO low  
Change of state of reception  
of AIS  
Change of state of reception  
of AIS  
Frame abort received  
Transmit FIFO underrun  
Receive FIFO full  
Change of state of reception  
of LOS  
Change of state of reception  
of LOS  
Receive FIFO overflow  
Reception of a severely  
errored frame  
Reception of consecutively  
errored FASs  
Transmit slip  
Receive remote signaling  
multiframe alarm  
Receive slip  
Receive slip  
Receive framing bit error  
Receive CRC-6 error  
Receive yellow alarm  
Receive FAS error  
Receive CRC-4 error  
Receive E-bit  
Change of receive frame  
alignment  
Receive AIS in timeslot 16  
Line code violation  
Receive PRBS error  
Receive auxiliary pattern  
Receive RAI  
Receive line code violation  
Receive PRBS error  
Pulse density violation  
Framing bit error counter  
overflow  
FAS error counter overflow  
CRC-4 error counter overflow  
CRC-6 error counter overflow  
Out of frame alignment  
counter overflow  
Out of frame alignment  
counter overflow  
Change of frame alignment  
counter overflow  
Receive E-bit counter  
overflow  
Line code violation counter  
overflow  
Line code violation counter  
overflow  
PRBS error counter overflow  
PRBS error counter overflow  
PRBS multiframe counter  
overflow  
PRBS multiframe counter  
overflow  
Multiframes out of alignment  
counter overflow  
Change of state of any Sa bit  
or Sa nibble  
Loop code detected  
One second timer  
Five second timer  
Jitter attenuator within 4 bits  
of overflow/underflow  
One second timer  
Receive new bit oriented  
message (debounced)  
Two second timer  
Signaling (CAS) bit change  
Signaling (AB or ABCD) bit  
change  
15  
MT9076  
Preliminary Information  
Error Counters  
All counters can be preset or cleared under software control  
Maskable occurrence interrupt  
Maskable overflow interrupt  
Counters can be latched on one second intervals  
T1/J1 Mode  
E1 Mode  
PRBS Error Counter (16-bit)  
Errored FAS Counter (8-bit)  
CRC Multiframe Counter (16-bit)  
E-bit Counter (10-bit)  
Framing Bit Error Counter (8-bit)  
Line Code Violation / Excessive Zeros  
Counter (16-bit)  
Out of Frame Alignment Counter (4-bit)  
Change of Frame Alignment Counter (4-bit)  
Multiframes Out of Sync Counter (8-bit)  
CRC-4 Error Counter (16-bit)  
PRBS Error Counter (8-bit)  
CRC Multiframe Counter (8-bit)  
Line Code Violation / Excessive Zeros  
Counter (16-bit)  
CRC-6 Error Counter (16-bit)  
Error Insertion  
T1/J1 Mode  
Bipolar Violations  
E1 Mode  
Bipolar Violations  
CRC-4 Errors  
FAS Errors  
CRC-6 Errors  
Ft Errors  
Fs Errors  
NFAS Errors  
Payload Errors  
Payload Errors  
Loss of Signal Error  
Loss of Signal Error  
Loopbacks  
Digital loopback  
Remote loopback  
ST-BUS loopback  
Payload loopback  
Metallic loopback  
Local timeslot loopback  
Remote timeslot loopback  
Per Timeslot Control  
The following features can be controlled on a per timeslot basis:  
Clear Channel Capability (only used in T1/J1)  
Choice of sourcing transmit signaling bits from microport or CSTi pin  
Remote timeslot loopback  
Local timeslot loopback  
PRBS insertion and reception  
Digital milliwatt pattern insertion  
Per channel inversion  
Transmit message mode  
16  
MT9076  
1.0 MT9076 Line Interface Unit (LIU)..................................................................................17  
1.1 Receiver .................................................................................................................................................17  
1.2 Transmitter .............................................................................................................................................18  
1.3 20 Mhz Clock..........................................................................................................................................21  
1.4 Phase Lock Loop (PLL)..........................................................................................................................22  
2.0 Clock Jitter Attenuation Modes....................................................................................23  
2.1 Jitter Attenuator FIFO.............................................................................................................................24  
2.2 IMA Mode...............................................................................................................................................24  
2.2.1 T1 Mode ......................................................................................................................................... 24  
2.2.2 E1 Mode ......................................................................................................................................... 24  
3.0 The Digital Interface ......................................................................................................24  
3.1 T1 Digital Interface .................................................................................................................................24  
3.2 Frame and Superframe Structure in T1 mode........................................................................................25  
3.2.1 Multiframing.................................................................................................................................... 25  
3.3 E1 Digital Interface.................................................................................................................................27  
3.3.1 Basic Frame Alignment .................................................................................................................. 28  
3.3.2 CRC-4 Multiframing in E1 mode..................................................................................................... 29  
3.3.3 CAS Signaling Multiframing in E1 mode......................................................................................... 30  
4.0 MT9076 Access and Control.........................................................................................30  
4.1 The Control Port Interface......................................................................................................................30  
4.2 Control and Status Register Access.......................................................................................................31  
4.3 Identification Code..................................................................................................................................31  
4.4 ST-BUS Streams....................................................................................................................................31  
5.0 Reset Operation (Initialization).....................................................................................32  
6.0 Transmit Data All Ones (TxAO) Operation ..................................................................33  
7.0 Data Link Operation ......................................................................................................33  
7.1 Data Link Operation in E1 mode ............................................................................................................33  
7.2 Data Link Operation in T1 mode ............................................................................................................33  
7.2.1 External Data Link .......................................................................................................................... 35  
7.2.2 Bit - Oriented Messaging................................................................................................................ 35  
8.0 Floating HDLC Channels ..............................................................................................35  
8.1 Channel Assignment ..............................................................................................................................35  
8.2 HDLC Description...................................................................................................................................36  
8.2.1 HDLC Frame structure ................................................................................................................... 36  
8.2.2 Data Transparency (Zero Insertion/Deletion) ................................................................................. 36  
8.2.3 Invalid Frames................................................................................................................................ 36  
8.2.4 Frame Abort.................................................................................................................................... 37  
xvii  
MT9076  
8.2.5 Interframe Time Fill and Link Channel States ................................................................................ 37  
8.2.6 Go-Ahead ....................................................................................................................................... 37  
8.3 HDLC Functional Description.................................................................................................................37  
8.3.1 HDLC Transmitter........................................................................................................................... 37  
8.3.2 HDLC Receiver............................................................................................................................... 38  
9.0 Slip Buffers .................................................................................................................... 40  
9.1 Slip Buffer in T1 Mode............................................................................................................................40  
9.2 Slip Buffer in E1 mode............................................................................................................................42  
10.0 Framing Algorithm ........................................................................................................ 43  
10.1 Frame Alignment in T1 Mode.................................................................................................................43  
10.2 Frame Alignment in E1 mode.................................................................................................................44  
10.2.1 Notes for Synchronization State Diagram (Figure 16).................................................................... 46  
10.3 Reframe..................................................................................................................................................46  
10.3.1 E1 Mode ........................................................................................................................................ 46  
10.3.2 T1 Mode ......................................................................................................................................... 46  
11.0 MT9076 Channel Signaling........................................................................................... 46  
11.1 Channel Signaling in T1 Mode ...............................................................................................................46  
11.2 Channel Signaling in E1 Mode...............................................................................................................47  
12.0 Loopbacks ..................................................................................................................... 48  
13.0 Performance Monitoring............................................................................................... 49  
13.1 Error Counters........................................................................................................................................49  
13.2 T1 Counters............................................................................................................................................49  
13.2.1 Framing Bit Error Counter (FC7-0)................................................................................................. 49  
13.2.2 Out Of Frame / Change Of Frame Alignment Counter (OOF3-0/COFA3-0) .................................. 49  
13.2.3 Multiframes out of Sync Counter (MFOOF7-MFOOF0).................................................................. 50  
13.2.4 CRC-6 Error Counter (CC15-0)...................................................................................................... 50  
13.2.5 Line Code Violation Error Counter (LCV15-LCV0)......................................................................... 50  
13.2.6 PRBS Error Counter (PS7-0).......................................................................................................... 50  
13.2.7 CRC Multiframe Counter for PRBS (PSM7-0)................................................................................ 50  
13.3 E1 Counters ...........................................................................................................................................50  
13.4 Errored FAS Counter (EFAS7-EFAS0) ..................................................................................................50  
13.5 E-bit Counter (EC15-0)...........................................................................................................................51  
13.6 Line Code Violation Error Counter (LCV15-LCV0).................................................................................51  
13.7 CRC-4 Error Counter (CC15-0)..............................................................................................................51  
13.8 PRBS Error Counter (PS7-0) .................................................................................................................51  
13.9 CRC Multiframe Counter for PRBS (PSM7-0)........................................................................................51  
xviii  
MT9076  
14.0 Error Insertion................................................................................................................52  
15.0 Per Time Slot Control Words ........................................................................................52  
15.1 Clear Channel Capability........................................................................................................................52  
15.2 Microport signaling .................................................................................................................................52  
15.3 Per Time Slot Looping............................................................................................................................52  
15.4 PRBS Testing.........................................................................................................................................53  
15.5 Digital Milliwatt........................................................................................................................................53  
15.6 Per Channel Inversion............................................................................................................................53  
15.7 Transmit Message..................................................................................................................................54  
16.0 Alarms ............................................................................................................................54  
16.1 Automatic Alarms ...................................................................................................................................54  
17.0 Detected Events.............................................................................................................55  
17.1 T1 mode .................................................................................................................................................55  
17.1.1 Severely Errored Frame Event....................................................................................................... 55  
17.1.2 Loop Code Detect........................................................................................................................... 55  
17.1.3 Pulse Density Violation Detect ....................................................................................................... 55  
17.1.4 Timer Outputs................................................................................................................................. 55  
17.2 E1 mode.................................................................................................................................................55  
17.2.1 Consecutive Frame Alignment Patterns (CONFAP)....................................................................... 55  
17.2.2 Receive Frame Alignment Signals ................................................................................................. 55  
17.2.3 Receive Non Frame Alignment Signal............................................................................................ 55  
17.2.4 Receive Multiframe Alignment Signals........................................................................................... 55  
18.0 Interrupts........................................................................................................................55  
18.1 Interrupts on T1 Mode............................................................................................................................56  
18.2 Interrupts on E1 Mode............................................................................................................................56  
19.0 Digital Framer Mode......................................................................................................57  
19.1 T1 Mode .................................................................................................................................................57  
19.1.1 E1 mode ......................................................................................................................................... 57  
20.0 Control and Status Registers .......................................................................................58  
20.1 T1 Mode .................................................................................................................................................58  
20.1.1 Master Control 1 (Page 01H) (T1).................................................................................................. 58  
20.1.2 Master Control 2 (Page 02H) (T1).................................................................................................. 69  
20.1.3 Master Status 1 (Page03H) (T1) .................................................................................................... 75  
20.1.4 Master Status 2 (Page04H) (T1).................................................................................................... 80  
20.1.5 Per Channel Transmit signaling (Pages 5 and 6) (T1) 88  
20.2 Per Time Slot Control Words (Pages 7 and 8) (T1) ...............................................................................90  
20.2.1 Per Channel Receive signaling (T1 and E1 mode) (Pages 9 and 0AH)......................................... 91  
20.3 E1 Mode.................................................................................................................................................92  
xix  
MT9076  
20.3.1 Master Control 1 (Page 01H) (E1).................................................................................................. 92  
20.4 Master Control 2 (Page-2)....................................................................................................................103  
20.4.1 Master Control 2 (Page 02H) (E1)................................................................................................ 103  
20.5 Master Status 1 (Page03H) (E1)..........................................................................................................109  
20.6 Master Status 1 (Page03H) (E1)..........................................................................................................110  
21.0 Master Status 2 (Page-4)............................................................................................ 117  
21.1 Master Status 2 (Page 04H) (E1).........................................................................................................117  
21.2 Per Channel Transmit signaling (Pages 5 and 6) (E1)........................................................................124  
21.3 Per Time Slot Control Words (Pages 7 and 8) (E1) .............................................................................125  
21.4 Per Channel Receive signaling (Pages 9 and 0AH) (E1).....................................................................126  
22.0 HDLC Control and Status (Page B for HDLC0, Page C for HDLC1 and Page D for  
HDLC2) ......................................................................................................................... 127  
23.0 Transmit National Bit Buffer (Page 0EH)................................................................... 137  
24.0 Receive National Bit Buffer (Page 0FH)..................................................................... 137  
25.0 AC/DC Electrical Characteristics ............................................................................... 138  
xx  
Preliminary Information  
MT9076  
1.0 MT9076 Line Interface Unit (LIU)  
1.1  
Receiver  
The receiver portion of the MT9076 LIU consists of an input signal peak detector, an optional equalizer with  
separate high pass sections, a smoothing filter, data and clock slicers and a clock extractor. Receive  
equalization gain can be set manually (i.e., software) or it can be determined automatically by peak detectors.  
The output of the receive equalizer is conditioned by a smoothing filter and is passed on to the clock and data  
slicer. The clock slicer output signal drives a phase locked loop, which generates an extracted clock (Exclk).  
This extracted clock is used to sample the output of the data comparator.  
In T1 mode, the receiver portion of the LIU can recover clock and data from the line signal for loop lengths of 0  
- 6000 ft. and tolerate jitter to the maximum specified by AT&T TR 62411(Figure 3).  
The LOS output pin function is selectable to indicate any combination of loss of signal and/or loss of basic  
frame synchronization condition.  
The LLOS (Loss of Signal) status bit indicates when the receive signal level is lower than the analog threshold  
for at least 1 millisecond, or when the number of consecutive received zeros exceeds the digital loss threshold.  
In E1 mode, the analog threshold is either of -20 dB or -40 dB. The digital loss threshold is either 32 or 192.  
In T1 mode, the receive LIU circuit requires a terminating resistor of 17.4across the device side of the  
receive 2.4:1 transformer.  
In E1 mode, the receive LIU circuit requires a terminating resistor of either 20.8or 13across the device side  
of the receive 2.4:1 transformer.  
The jitter tolerance of the clock extractor circuit exceeds the requirements of TR 62411 in T1 mode (see Figure  
3) and G.823 in E1 mode (see Figure 4).  
Peak to Peak  
Jitter Amplitude  
(log scale)  
138UI  
100UI  
28UI  
10UI  
1.0UI  
0.4UI  
Jitter Frequency  
(log scale)  
0.1Hz 1.0Hz  
10Hz  
4.9Hz  
100Hz  
1.0kHz 10kHz 100kHz  
Figure 3 - Input Jitter Tolerance as Recommended by TR-62411 (T1)  
17  
MT9076  
Preliminary Information  
Peak to Peak  
Jitter Amplitude  
(log scale)  
18UI  
MT9076  
Tolerance  
1.5UI  
0.2UI  
Jitter Frequency  
(log scale)  
1.667Hz  
20Hz  
2.4kHz 18kHz 100kHz  
Figure 4 - Input Jitter Tolerance as Recommended by G.823 and ETSI 300 011 (E1)  
Transmitter  
1.2  
The transmit portion of the MT9076 LIU consists of a high speed digital-to-analog converter and  
complementary line drivers.  
When a pulse is to be transmitted, a sequence of digital values (dependent on transmit equalization) are read  
out of a ROM by a high speed clock. These values drive the digital-to-analog converter to produce an analog  
signal, which is passed to the complementary line drivers.  
The complementary line drivers are designed to drive a 1:2.4 step-up transformer in T1 mode (see Figure 4 for  
T1 mode) and either a 1:2 or 1:2.4 step-up transformer in E1 mode (see Figure 5 for E1 mode). A 0.47uF  
capacitor is required between the TTIP and the transmit transformer. Resistors RT (as shown in Figure 4) are  
for termination for transmit return loss. The values of RT may be optimized for T1 mode, E1 120lines, E1 75Ω  
lines or set at a compromise value to serve multiple applications. Program the Tx LIU Control Word (page 02H,  
address 11H) to adjust the pulse amplitude accordingly.  
Alternatively, the pulse level and shape may be discretely programmed by writing to the Custom Pulse Level  
registers (page 2, addresses 1CH to 1FH) and setting the Custom Transmit Pulse bit high (bit 3 of the Tx LIU  
Control Word). In this case the output of each of the registers directly drives the D/A converter going to the line  
driver. Tables 1 and 2 show recommended transmit pulse amplitude settings.  
In T1 mode, the template for the transmitted pulse (the DSX-1 template) is shown in Figure 8. The nominal  
peak voltage of a mark is 3 volts. The ratio of the amplitude of the transmit pulses generated by TTIP and  
TRING lie between 0.95 and 1.05.  
In E1 mode, the template for the transmitted pulse, as specified in G.703, is shown in Figure 8. The nominal  
peak voltage of a mark is 3 volts for 120 twisted pair applications and 2.37 volts for 75 coax applications.  
The ratio of the amplitude of the transmit pulses generated by TTIP and TRING lie between 0.95 and 1.05.  
18  
Preliminary Information  
MT9076  
R
Fuse  
T
1:2.4  
0.47uF  
Tx  
TTIP  
R
T
Fuse  
Fuse  
TRING  
RT: 2.4  
+3.3 V  
1:2.4  
RTIP  
17.36 Ω  
Fuse  
RRING  
Rx  
Figure 5 - Analog Line Interface (T1)  
Functional Description  
Name  
TXL2-0 Transmit Line Build Out 2 - 0. Setting these bits shapes the transmit pulse as detailed in the table  
below:  
TXL2  
TXL1  
TXL0  
Line Build Out  
0 to 133 feet/ 0 dB  
133 to 266 feet  
266 to 399 feet  
399 to 533 feet  
533 to 655 feet  
-7.5 dB  
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
-15 dB  
-22.5 dB  
After reset these bits are zero.  
Table 1 - Transmit Line Build Out (T1)  
Tx  
1:2.4 (WR=0)  
Fuse  
RT  
RT  
1:2 (WR=1)  
0.47uF  
TTIP  
TRING  
RTIP  
Fuse  
RT: Termination resis-  
tor. Please check  
Table 2 for specific  
resistor values.  
+3.3V  
Fuse  
Fuse  
1:2.4  
20.83 Ω  
RRING  
Rx  
Figure 6 - Analog Line Interface (E1)  
19  
MT9076  
Preliminary Information  
Name  
Functional Description  
WR  
Winding Ratio. Set this pin low if a 1:2.4 transformer is used on the transmit side. Set this  
pin high if a 1:2 transformer is used.  
TX2-0  
Transmit pulse amplitude. Select the TX2 –TX0 bits according to the line type, value of  
termination resistors (RT), and transformer turns ratio used  
TX2 TX1 TX0 Line Impedance() RT ()  
WR=0 WR=1  
Transformer Ratio  
WR=0 WR=1  
1:2  
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
1
1
120  
120  
120  
120 / 75  
75  
75  
0
0
0
0
1:2.4  
1:1  
1:1  
1:2  
1:2  
1:2  
1:1  
1:2  
1:2  
10.4 15  
8.4  
0
0
6.5  
8.4  
1:2.4  
1:2.4  
1:2.4  
1:1  
1:2.4  
1:2.4  
12.1  
0
0
9.1  
12.1  
75  
75 / 120  
After reset these bits are zero.  
Table 2 - Transmit Pulse Amplitude (E1)  
1.20  
1.05  
0.95  
0.90  
0.80  
0.50  
0.05  
0
-0.05  
-0.26  
-0.45  
Time, in unit intervals (UI)  
NOTE: 1 Unit Interval = 648 nanoseconds  
Figure 7 - Pulse Template (T1.403)(T1)  
20  
Preliminary Information  
MT9076  
Time (Nanoseconds)  
Time U.I.  
-499 -253 -175 -175 -78  
-.77 -.39 -.27 -.27 -.12  
0
0
175 220 499 752 ---  
.27 .34 .77 1.16 ---  
.05 ---  
---  
---  
---  
Normalized Amplitude  
.05  
.05  
.8  
1.2  
1.2  
1.05 1.05 -.05 .05  
Table 3 - Maximum Curve for Figure 8  
Time (Nanoseconds)  
Time U.I.  
-499 -149 -149 -97  
-.77 -.23 -.23 -.15  
0
97  
.15  
.9  
149 149 298 395 603 752  
0
.23  
.5  
.23  
.46  
.61  
.93  
1.16  
Normalized Amplitude  
-.05 -.05 .5  
.9  
.95  
-.45 -.45 -.26 -.05 -.05  
Table 4 - Minimum Curve for Figure 8  
Percentage of Nominal  
Peak Voltage  
269nS  
120  
110  
100  
90  
244nS  
194nS  
80  
50  
20  
0
-10  
-20  
Nominal Pulse  
219nS  
488nS  
Figure 8 - Pulse Template (G.703)(E1)  
1.3  
20 Mhz Clock  
The MT9076 requires a 20 Mhz a clock. This may provided by a 50 ppm oscillator as per Figure 10.  
21  
MT9076  
Preliminary Information  
+3.3V  
Vdd  
20MHz  
OUT  
OSC1  
OSC2  
.1µF  
GND  
(open)  
Figure 9 - Clock Oscillator Circuit  
Alternatively, a crystal oscillator may be used. A complete oscillator circuit made up of a crystal, resistors and  
capacitors is shown in Figure 10. The crystal specification is as follows.  
Frequency:  
20MHz  
50ppm  
Fundamental  
Parallel  
32pF  
Tolerance:  
Oscillation Mode:  
Resonance Mode:  
Load Capacitance:  
Maximum Series Resistance:  
Approximate Drive Level:  
35Ω  
1mW  
20MHz  
OSC1  
56pF  
39pF  
1MΩ  
1µH*  
100Ω  
OSC2  
Note: the 1µH inductor is optional  
Figure 10 - Crystal Oscillator Circuit  
1.4  
Phase Lock Loop (PLL)  
The MT9076 contains a PLL, which can be locked to either an input 4.096 Mhz clock or the extracted line  
clock.The PLL will attenuate jitter from less than 2.5 Hz and roll-off at a rate of 20 dB/decade. Its intrinsic jitter  
is less than 0.02 UI. The PLL will meet the jitter transfer characteristics as specified by AT&T document  
TR 62411and the relevant recommendations as shown in Figure 12.  
22  
Preliminary Information  
MT9076  
dB  
-0.5  
0
-20 dB/decade  
19.5  
10  
40  
400  
10K  
Frequency (Hz)  
Figure 11 - TR 62411 Jitter Attenuation Curve  
2.0 Clock Jitter Attenuation Modes  
MT9076 has three basic jitter attenuation modes of operation, selected by the BS/LS and S/FR/Exclki control  
pins.  
System Bus Synchronous Mode  
Line Synchronous Mode  
Free-run mode  
Depending on the mode selection above, the PLL can either attenuate transmit clock jitter or the receive clock  
jitter. Table 5 shows the appropriate configuration of each control pin to achieve the appropriate mode and  
Jitter attenuation capability of the MT9076.  
Mode Name  
BS/LS  
S/FR/Exclki  
Note  
System Bus Synchronous  
Line Synchronous  
Free-Run  
1
0
x
1
1
0
PLL locked to C4b.  
PLL locked to Exclk.  
PLL free - running.  
Table 5 - Selection of clock jitter attenuation modes using the M/S and MS/FR pins  
In System Bus Synchronous mode, pins C4b and F0b are always configured as inputs, while in the Line  
Synchronous and Free-Run modes C4b and F0b are configured as outputs.  
Referring to the mode names given in Table 5 the basic operation of the jitter attenuation modes are:  
In System Bus Synchronous mode an external clock is applied to C4b. The applied clock is dejittered by  
the internal PLL before being used to synchronize the transmitted data. The clock extracted (with no  
jitter attenuation performed) from the receive data can be monitored on pin Exclk.  
23  
MT9076  
Preliminary Information  
In Line Synchronous mode, the clock extracted from the receive data is dejittered using the internal PLL  
and then output on pin C4b. Pin Exclk provides the extracted receive clock before it has been dejittered.  
The transmit data is synchronous to the clean receive clock.  
In Free-Run mode the transmit data is synchronized to the internally generated clock. The internal clock  
is output on pin C4b. The clock signal extracted from the receive data is not dejittered and is output  
directly on Exclk.  
2.1  
Jitter Attenuator FIFO  
In System Bus Synchronous operation, a data buffer is required between the jittered input clock and the clean  
transmit clock. In normal T1 mode, the transmit slip buffer performs this function. In T1 IMA mode, the transmit  
slip buffer is unused, instead a jitter attenuator FIFO is employed. In an E1 mode System Bus Synchronous  
configuration, the jitter attenuator FIFO is always used. In this case the C4b signal clocks the data into the  
FIFO, the PLL de-jitters the C4b clock and the resulting clean C4b signal clocks the data out of the FIFO.  
The JA meets the jitter transfer characteristics as proposed by ETSI ETS 300 011, G.735 and the relevant  
recommendations as shown in Figure 12. The JA FIFO depth can be selected to be from 16 to 128 words deep,  
in multiples of 16 (2-bit) words. Its read pointer can be centered by changing the JFC bit (address 13H of page  
02H) to provide maximum jitter tolerance. If the read pointer should come within 4 bits of either end of the  
FIFO, the read clock frequency will be increased or decreased by 0.0625 UI to correct the situation. The  
maximum time needed to centre is T  
= 3904 Depth ns, where Depth is the selected JA FIFO depth. During  
max  
this time the JA will not attenuate jitter.  
2.2  
IMA Mode  
2.2.1  
T1 Mode  
In T1 IMA Mode, neither the transmit nor the receive slip buffers are activated. Channel Associated signaling  
(CAS) and HDLC operation is not supported. The input pin C4b accepts a 1.544 MHz clock and it clocks  
incoming data from DSTi into a jitter attenuator FIFO. This clock is dejittered with the internal PLL. The  
dejittered clock clocks data out of the FIFO for transmission onto the line. Receive clock (1.544 MHz) and data  
is extracted from the line and routed to pins Exclk and DSTo respectively. The receive clock Exclk is not  
dejittered before being driven off chip. For operation in IMA mode, the MT9076 should be programmed in  
System Bus Synchronous mode (BS/LS and S/FR/Exclki set high).  
2.2.2  
E1 Mode  
In E1 IMA Mode neither the transmit nor the receive slip buffers are activated. The input pin C4b accepts a  
2.048 MHz clock and it clocks incoming data from DSTi into a jitter attenuator FIFO. This clock is dejittered with  
the internal PLL. The dejittered clock clocks data out of the FIFO for transmission onto the line. Receive clock  
(2.048 MHz) and data is extracted from the line and routed to pins Exclk and DSTo respectively. The receive  
clock Exclk is not dejittered before being driven off chip. For operation in IMA mode, the MT9076 should be  
programmed in System Bus Synchronous mode (BS/LS and S/FR/Exclki set high).  
3.0 The Digital Interface  
3.1  
T1 Digital Interface  
In T1 mode, DS1 frames are 193 bits long and are transmitted at a frame repetition rate of 8000 Hz, which  
results in an aggregate bit rate of 193 bits x 8000/sec= 1.544 Mbits/sec. The actual bit rate is 1.544 Mbits/sec  
+/-50 ppm optionally encoded in B8ZS format. The Zero Suppression control register (page 1, address 15H,)  
selects either B8ZS encoding, forced one stuffing or alternate mark inversion (AMI) encoding. Basic frames are  
divided into 24 time slots numbered 1 to 24. Each time slot is 8 bits in length and is transmitted most significant  
bit first (numbered bit 1). This results in a single time slot data rate of 8 bits x 8000/sec. = 64 kbits/sec.  
24  
Preliminary Information  
MT9076  
It should be noted that the Mitel ST-BUS has 32 channels numbered 0 to 31. When mapping to the DS1  
payload only the first 24 time slots and the last (time slot 31, for the overhead bit) of an ST-BUS are used (see  
Table 6). All unused channels are tristate.  
When signaling information is written to the MT9076 in T1 mode using ST-BUS control links (as opposed to  
direct writes by the microport to the on - board signaling registers), the CSTi channels corresponding to the  
selected DSTi channels streams are used to transmit the signaling bits.  
Since the maximum number of signaling bits associated with any channel is 4 (in the case of ABCD), only half  
a CSTi channel is required for sourcing the signaling bits. The choice of which half of the channel to use is  
selected by the control bit MSN (page 01H address 14H). The same control bit selects which half of the CSTo  
channel will contain receive signaling information (the other nibble in the channel being tristate). Unused  
channels are tristate.  
The most significant bit of an eight bit ST-BUS channel is numbered bit 7 (see Mitel Application Note MSAN-  
126). Therefore, ST-BUS bit 7 is synonymous with DS1 bit 1; bit 6 with bit 2: and so on.  
DS1 Timeslots  
1
0
2
1
3
2
4
3
5
4
6
5
7
6
8
7
9
7
10 11 12 13 14 15  
16  
15  
Voice/Data Channels  
(DSTi/o and CSTi/o)  
9
10 11 12 13 14  
Ds1 Timeslots  
17 18 19 20 21 22 23 24  
-
-
-
-
-
-
-
-
Voice/Data Channels  
(DSTi/o and CSTi/o)  
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30  
31  
Sbit  
x
x
x
x
x
x
x
Table 6 - ST-BUS vs. DS1 to Channel Relationship(T1)  
Frame and Superframe Structure in T1 mode  
3.2  
3.2.1  
Multiframing  
In T1 mode, DS1 trunks contain 24 bytes of serial voice/data channels bundled with an overhead bit. The frame  
overhead bit contains a fixed repeating pattern used to enable DS1 receivers to deliniate frame boundaries.  
Overhead bits are inserted once per frame at the beginning of the transmit frame boundary. The DS1 frames  
are further grouped in bundles of frames, generally 12 (for D4 applications) or 24 frames (for ESF - extended  
superframe applications) deep. Table 7 and 8 illustrate the D4 and ESF frame structures respectively.  
For D4 links the frame structure contains an alternating 101010... pattern inserted into every second overhead  
bit position. These bits are intended for determination of frame boundaries, and they are referred to as Ft bits.  
A separate fixed pattern, repeating every superframe, is interleaved with the Ft bits. This fixed pattern  
(001110), is used to deliniate the 12 frame superframe. These bits are referred to as the Fs bits. In D4 frames  
# 6 and #12, the LSB of each channel byte may be replaced with A bit (frame #6) and B bit (frame #12)  
signaling information.  
For ESF links the 6 bit framing pattern 001011, inserted into every 4th overhead bit position, is used to  
deliniate both frame and superframe boundaries. Frames #6, 12, 18 and 24 contain the A, B, C and D signaling  
bits, respectively. A 4 kHz data link is embedded in the overhead bit position, interleaved between the framing  
pattern sequence (FPS) and the transmit CRC-6 remainder (from the calculation done on the previous  
superframe), see Table 8.  
The SLC-96 frame structure is similar to the D4 frame structure, except a facility management overlay is  
superimposed over the erstwhile Fs bits, see Table 9.  
The protocol appropriate for the application is selected via the Framing Mode Selection Word, address 10H of  
Master Control page 1. In T1 mode, MT9076 is capable of generating the overhead bit framing pattern and (for  
ESF links) the CRC remainder for transmission onto the DS1 trunk. The beginning of the transmit multiframe  
may be determined by any of the following criteria:  
25  
MT9076  
Preliminary Information  
(i) It may free - run with the internal multiframe counters;  
(ii) The multiframe counters may be reset with the external hardware pin TxMF. If this signal is not  
synchronous with the current transmit frame count it may cause the far end to go temporarily out of sync.  
(iii) Under software control (by setting the TxSYNC bit in page 01 address 12H) the transmit multiframe  
counters will be synchronized to the framing pattern present in the overhead bits multiplexed into channel  
31 bit 0 of the incoming 2.048 Mb/s digital stream DSTi. Note that the overhead bits extracted from the  
receive signal are multiplexed into outgoing DSTo channel 31 bit 0.  
(iv) In SLC - 96 mode the transmit frame counters synchronize to the framing pattern clocked in on the TXDL  
input  
Frame #  
Ft  
Fs  
Signaling  
1
2
1
0
0
1
1
1
0
3
0
1
0
1
0
4
5
6
A
B
7
8
9
10  
11  
12  
Table 7 - D4 Superframe Structure(T1)  
Frame #  
FPS  
FDL  
CRC  
Signaling  
1
2
X
CB1  
3
X
X
X
X
X
X
X
X
X
X
X
4
0
0
1
0
1
1
5
6
CB2  
CB3  
CB4  
CB5  
CB6  
A
B
C
D
7
8
9
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
Table 8 - ESF Superframe Structure (T1)  
26  
Preliminary Information  
MT9076  
Frame # Ft  
Fs Notes Frame # Ft  
Fs Notes Frame # Ft  
Fs  
Notes  
1
2
1
0
1
0
1
0
1
0
1
0
1
0
25  
26  
27  
28  
29  
30  
31  
32  
33  
34  
35  
36  
37  
38  
39  
40  
41  
42  
43  
44  
45  
46  
47  
48  
1
0
1
0
1
0
1
0
1
0
1
0
C
o
n
c
e
n
t
49  
50  
51  
52  
53  
54  
55  
56  
57  
58  
59  
60  
61  
62  
63  
64  
65  
66  
67  
68  
69  
70  
71  
72  
1
0
1
0
1
0
1
0
1
0
1
0
0
0
0
1
1
1
0
0
0
1
1
1
R
e
s
y
n
c
h
r
X
X
X
X
X
X
X
X
X
X
X
S
S
S
C
C
C
A
A
L
S = Spoiler Bits  
3
4
5
6
C = Maintenance Field Bits  
7
8
r
9
a
t
10  
11  
12  
13  
14  
15  
16  
17  
18  
19  
20  
21  
22  
23  
24  
o
n
i
o
r
A = Alarm Field Bits  
z
a
t
F
i
i
e
l
L = Line Switch Field Bits  
o
n
d
L
d
a
t
B
i
L
t
L
a
s
S
S = Spoiler Bits  
Table 9 - SLC-96 Framing Structure(T1)  
3.3  
E1 Digital Interface  
PCM 30 (E1) basic frames are 256 bits long and are transmitted at a frame repetition rate of 8000 Hz, which  
results in an aggregate bit rate of 256 bits x 8000/sec = 2.048 Mbits/sec. The actual bit rate is 2.048 Mbits/sec  
+/-50 ppm encoded in HDB3 format. The HDB3 control bit (page 01H, address 15H, bit 5) selects either HDB3  
encoding or alternate mark inversion (AMI) encoding. Basic frames are divided into 32 time slots numbered 0  
to 31, see Figure 31. Each time slot is 8 bits in length and is transmitted most significant bit first (numbered bit  
1). This results in a single time slot data rate of 8 bits x 8000/sec. = 64 kbits/sec.  
It should be noted that the Mitel ST-BUS also has 32 channels numbered 0 to 31, but the most significant bit of  
an eight bit channel is numbered bit 7 (see Mitel Application Note MSAN-126). Therefore, ST-BUS bit 7 is  
synonymous with PCM 30 bit 1; bit 6 with bit 2: and so on (Figure 31).  
PCM 30 time slot 0 is reserved for basic frame alignment, CRC-4 multiframe alignment  
and  
the  
communication of maintenance information. In most configurations time slot 16 is reserved for either Channel  
Associated signaling (CAS or ABCD bit signaling) or Common Channel signaling (CCS). The remaining 30  
time slots are called channels and carry either PCM encoded voice signals or digital data. Channel alignment  
and bit numbering is consistent with time slot alignment and bit numbering. However, channels are numbered 1  
to 30 and relate to time slots as per Table 10.  
PCM 30 Timeslots  
0
0
1,2,3...15  
1,2,3...15  
16 17,18,19,... 31  
16 17,18,19,... 31  
Voice/Data Channels  
(DSTi/o and CSTi/o)  
Table 10 - ST-BUS vs. PCM-30 to Channel Relationship(E1)  
27  
MT9076  
Preliminary Information  
3.3.1  
Basic Frame Alignment  
Time slot 0 of every basic frame is reserved for basic frame alignment and contains either a Frame Alignment  
Signal (FAS) or a Non-Frame Alignment Signal (NFAS). FAS and NFAS occur in time slot zero of consecutive  
basic frames as shown in Table 12. Bit two is used to distinguish between FAS (bit two = 0) and NFAS (bit two  
= 1).  
Basic frame alignment is initiated by a search for the bit sequence 0011011 which appears in the last seven bit  
positions of the FAS, see the Frame Algorithm section. Bit position one of the FAS can be either a CRC-4  
remainder bit or an international usage bit.  
Bits four to eight of the NFAS (i.e., S - S ) are additional spare bits which may be used as follows:  
a4  
a8  
S
to S may be used in specific point-to-point applications (e.g. transcoder equipments conforming to  
a4 a8  
G.761)  
S
may be used as a message-based data link for operations, maintenance and performance  
a4  
monitoring  
S
to S are for national usage  
a5  
a8  
A maintenance channel or data link at 4,8,12,16,or 20 kHz for selected S bits is provided by the MT9076 in E1  
a
mode to implement these functions. Note that for simplicity all S bits including Sa4 are collectively called  
a
national bits throughout this document.  
Bit three (designated as “A”), the Remote Alarm Indication (RAI), is used to indicate the near end basic frame  
synchronization status to the far end of a link. Under normal operation, the A (RAI) bit should be set to 0, while  
in alarm condition, it is set to 1.  
Bit position one of the NFAS can be either a CRC-4 multiframe alignment signal, an E-bit or an international  
usage bit. Refer to an approvals laboratory and national standards bodies for specific requirements.  
PCM 30 Channel Zero  
CRC  
CRC  
Frame/Type  
1
2
3
4
5
6
7
8
0/FAS  
C
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
A
0
1
1
0
1
1
1
1/NFAS  
2/FAS  
0
S
S
S
S
S
a8  
a4  
a5  
a6  
a7  
C
1
1
0
1
1
2
3/NFAS  
4/FAS  
0
A
0
S
S
S
S
S
a8  
a4  
a5  
a6  
a7  
C
1
1
0
1
1
3
5/NFAS  
6/FAS  
1
A
0
S
S
S
S
S
a8  
a4  
a5  
a6  
a7  
C
1
1
0
1
1
4
7/NFAS  
8/FAS  
0
A
0
S
S
S
S
S
a8  
a4  
a5  
a6  
a7  
C
1
1
0
1
1
1
9/NFAS  
10/FAS  
11/NFAS  
12/FAS  
13/NFAS  
14/FAS  
15/NFAS  
1
A
0
S
S
S
S
S
a8  
a4  
a5  
a6  
a7  
C
1
1
0
1
1
2
1
A
0
S
S
S
S
S
a8  
a4  
a5  
a6  
a7  
C
1
1
0
1
1
3
E
A
0
S
S
S
S
S
a8  
1
a4  
a5  
a6  
a7  
C
1
1
0
1
1
4
E
A
S
S
S
S
S
a8  
2
a4  
a5  
a6  
a7  
Table 11 - FAS and NFAS Structure  
indicates position of CRC-4 multiframe alignment signa  
28  
Preliminary Information  
MT9076  
3.3.2  
CRC-4 Multiframing in E1 mode  
The primary purpose for CRC-4 multiframing is to provide a verification of the current basic frame alignment,  
although it can also be used for other functions such as bit error rate estimation. The CRC-4 multiframe  
consists of 16 basic frames numbered 0 to 15, and has a repetition rate of 16 frames X 125 microseconds/  
frame = 2 msec.  
CRC-4 multiframe alignment is based on the 001011 bit sequence, which appears in bit position one of the first  
six NFASs of a CRC-4 multiframe.  
The CRC-4 multiframe is divided into two submultiframes, numbered 1 and 2, which are each eight basic  
frames or 2048 bits in length.  
The CRC-4 frame alignment verification functions as follows. Initially, the CRC-4 operation must be activated  
and CRC-4 multiframe alignment must be achieved at both ends of the link. At the local end of a link, all the bits  
4
4
of every transmit submultiframe are passed through a CRC-4 polynomial (multiplied by X then divided by X +  
X + 1), which generates a four bit remainder. This remainder is inserted in bit position one of the four FASs of  
the following submultiframe before it is transmitted (see Table 12).  
The submultiframe is then transmitted and, at the far end, the same process occurs. That is, a CRC-4  
remainder is generated for each received submultiframe. These bits are compared with the bits received in  
position one of the four FASs of the next received submultiframe. This process takes place in both directions of  
transmission.  
When more than 914 CRC-4 errors (out of a possible 1000) are counted in a one second interval, the framing  
algorithm will force a search for a new basic frame alignment. See Frame Algorithm section for more details.  
The result of the comparison of the received CRC-4 remainder with the locally generated remainder will be  
transported to the far end by the E-bits. Therefore, if E = 0, a CRC-4 error was discovered in a submultiframe  
1
1 received at the far end; and if E = 0, a CRC-4 error was discovered in a submultiframe 2 received at the far  
2
end. No submultiframe sequence numbers or re-transmission capabilities are supported with layer 1 PCM 30  
protocol. See ITU-T G.704 and G.706 for more details on the operation of CRC-4 and E-bits.  
There are two CRC multiframe alignment algorithm options selected by the AUTC control bit (address 10H,  
page 01H). When AUTC is zero, automatic CRC-to-non-CRC interworking is selected. When AUTC is one and  
ARAI is low, if CRC-4 multiframe alignment is not found in 400 msec, the transmit RAI will be continuously high  
until CRC-4 multiframe alignment is achieved.  
The control bit for transmit E bits (TE, address 11H of page 01H) will have the same function in both states of  
AUTC. That is, when CRC-4 synchronization is not achieved the state of the transmit E-bits will be the same as  
the state of the TE control bit. When CRC-4 synchronization is achieved the transmit E-bits will function as per  
ITU-T G.704. Table 12 outlines the operation of the AUTC, ARAI and TALM control bits of the MT9076.  
29  
MT9076  
Preliminary Information  
AUTC  
ARAI  
TALM  
Description  
0
0
X
Automatic CRC-interworking is activated. If no valid CRC MFAS is being received,  
transmit RAI will flicker high with every reframe (8msec.), this cycle will continue  
for 400 msec., then transmit RAI will be low continuously. The device will stop  
searching for CRC MFAS, continue to transmit CRC-4 remainders, stop CRC-4  
processing, indicate CRC-to-non-CRC operation and transmit E-bits to be the  
same state as the TE control bit (page 01H, address 16H).  
0
0
1
1
1
0
0
1
X
Automatic CRC-interworking is activated. Transmit RAI is low continuously.  
Automatic CRC-interworking is activated. Transmit RAI is high continuously.  
Automatic CRC-interworking is de-activated. If no valid CRC MFAS is being  
received, transmit RAI flickers high with every reframe (8 msec.), this cycle  
continues for 400 msec, then transmit RAI becomes high continuously. The  
device continues to search for CRC MFAS and transmit E-bits are the same state  
as the TE control bit. When CRCSYN = 0, the CRC MFAS search is terminated  
and the transmit RAI goes low.  
1
1
1
1
0
1
Automatic CRC-interworking is de-activated. Transmit RAI is low continuously.  
Automatic CRC-interworking is de-activated. Transmit RAI is high continuously.  
Table 12 - Operation of AUTC, ARAI and TALM Control Bits (E1 Mode)  
3.3.3  
CAS Signaling Multiframing in E1 mode  
The purpose of the signaling multiframing algorithm is to provide a scheme that will allow the association of a  
specific ABCD signaling nibble with the appropriate PCM 30 channel. Time slot 16 is reserved for the  
communication of Channel Associated signaling (CAS) information (i.e., ABCD signaling bits for up to 30  
channels). Refer to ITU-T G.704 and G.732 for more details on CAS multiframing requirements.  
A CAS signaling multiframe consists of 16 basic frames (numbered 0 to 15), which results in a multiframe  
repetition rate of 2 msec. It should be noted that the boundaries of the signaling multiframe may be completely  
distinct from those of the CRC-4 multiframe. CAS multiframe alignment is based on a multiframe alignment  
signal (a 0000 bit sequence), which occurs in the most significant nibble of time slot 16 of basic frame 0 of the  
CAS multiframe. Bit 6 of this time slot is the multiframe alarm bit (usually designated Y). When CAS  
multiframing is acquired on the receive side, the transmit Y-bit is zero; when CAS multiframing is not acquired,  
the transmit Y-bit is one. Bits 5, 7 and 8 (usually designated X) are spare bits and are normally set to one if not  
used.  
Time slot 16 of the remaining 15 basic frames of the CAS multiframe (i.e., basic frames 1 to 15) are reserved  
for the ABCD signaling bits for the 30 payload channels. The most significant nibbles are reserved for channels  
1 to 15 and the least significant nibbles are reserved for channels 16 to 30. That is, time slot 16 of basic frame  
1 has ABCD for channel 1 and 16, time slot 16 of basic frame 2 has ABCD for channel 2 and 17, through to  
time slot 16 of basic frame 15 has ABCD for channel 15 and 30.  
4.0 MT9076 Access and Control  
4.1  
The Control Port Interface  
The control and status registers of the MT9076 are accessible through a non-multiplexed parallel  
microprocessor port. The parallel port may be configured for Motorola style control signals (by setting pin INT/  
MOT low) or Intel style control signals (by setting pin INT/MOT high).  
30  
Preliminary Information  
MT9076  
4.2  
Control and Status Register Access  
The controlling microprocessor gains access to specific registers of the MT9076 through a two step process.  
First, writing to the Command/Address Register (CAR) selects one of the 15 pages of control and status  
registers (CAR address: AC4 = 0, AC3-AC0 = don't care, CAR data D7 - D0 = page number). Second, each  
page has a maximum of 16 registers that are addressed on a read or write to a non-CAR address (non-CAR:  
address AC4 = 1, AC3-AC0 = register address, D7-D0 = data). Once a page of memory is selected, it is only  
necessary to write to the CAR when a different page is to be accessed. See the AC Electrical Characteristics  
section.  
Page Address D7 - D0  
Register Description  
Processor Access  
ST-BUS Access  
00000001 (01H)  
00000010 (02H)  
00000011 (03H)  
00000100 (04H)  
00000101 (05H)  
00000110 (06H)  
00000111 (07H)  
00001000 (08H)  
00001001 (09H)  
00001010 (0AH)  
00001011 (0BH)  
00001011 (0CH)  
00001011 (0DH)  
00001011 (0EH)  
00001011 (0FH)  
Master  
Control  
R/W  
R/W  
R
- - -  
Master  
Status  
- - -  
R/W  
R/W  
R/W  
Per Channel Transmit signaling  
Per Channel Transmit signaling  
Per Time Slot Control  
CSTi  
CSTi  
- - -  
- - -  
CSTo  
CSTo  
- -  
Per Time Slot Control  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R
Per Channel Receive signaling  
Per Channel Receive signaling  
HDLC0 Control and Status  
HDLC1 Control and Status  
HDLC2 Control and Status  
Tx National Bit Buffer  
---  
---  
---  
Rx National Bit Buffer  
---  
Table 13 - Page Summary  
Please note that for microprocessors with read/write cycles less than 200 ns, a wait state or a dummy operation  
(for C programming) between two successive read/write operations to the HDLC FIFO is required.  
Table 13 associates the MT9076 control and status pages with access and page descriptions.  
4.3  
Identification Code  
The MT9076 shall be identified by the code 01111000, read from the identification code status register (page  
03H, address 1FH).  
4.4  
ST-BUS Streams  
In T1 mode, there is one control and one status ST-BUS stream that can be used to program / access channel  
associated signaling nibbles. CSTo contains the received channel associated signaling bits, and for those  
channels whose Per Time Slot Control word bit 1 "RPSIG" is set low, CSTi is used to control the transmit  
channel associated signaling. The DSTi and DSTo streams contain the transmit and receive voice and digital  
data. Only 24 of the 32 ST-BUS channels are used for each of DSTi, DSTo, CSTi and CSTo. In each case  
individual channel mapping is as illustrated in Table 6, “ST-BUS vs. DS1 to Channel Relationship(T1),on  
page 25.  
In E1 mode, ST-BUS streams can also be used to access channel associated signaling nibbles. CSTo contains  
the received channel associated signaling bits (e.g., ITU-T R1 and R2 signaling) ,and for those channels whose  
31  
MT9076  
Preliminary Information  
Per Time Slot Control word bit 1 "RPSIG" is set low, CSTi is used to control the transmit channel associated  
signaling. The DSTi and DSTo streams contain the transmit and receive voice and digital data.  
Only 30 of the 32 ST-BUS channels are used for each of DSTi, DSTo, CSTi and CSTo. In each case individual  
channel mapping is as illustrated in Table 10 Time slot to Channel Relationship.  
5.0 Reset Operation (Initialization)  
The MT9076 can be reset using the hardware RESET pin (pin 11 in PLCC, pin 64 in LQFP) or the software  
reset bit RST (page 1H, address 1AH) . When the device emerges from its reset state it will begin to function  
with the default settings described in Table 14 (T1) and Table 15 (E1). All control registers are set to 00H. A  
reset operation takes 1 full frame (125 us) to complete.  
Function  
Status  
Mode  
Loopbacks  
SLC-96  
D4  
Deactivated  
Deactivated  
Deactivated  
Deactivated  
Serial Mode  
CAS Registers  
Deactivated  
masked  
Zero Coding  
Line Codes  
Data Link  
signaling  
AB/ABCD Bit Debounce  
Interrupts  
Error Insertion  
HDLCs  
Deactivated  
Deactivated  
Cleared  
Counters  
Transmit Data  
All Ones  
Table 14 - Reset Status(T1)  
Function  
Status  
Mode  
Loopbacks  
Termination  
Deactivated  
Transmit FAS  
Transmit non-FAS  
Transmit MFAS (CAS)  
Data Link  
C 0011011  
n
1/S 1111111  
n
00001111  
Deactivated  
Activated  
CRC Interworking  
signaling  
CAS Registers  
Deactivated  
Masked  
ABCD Bit Debounce  
Interrupts  
RxMF Output  
Error Insertion  
HDLCs  
signaling Multiframe  
Deactivated  
Deactivated  
Cleared  
Counters  
Transmit Data  
All Ones  
Table 15 - Reset Status (E1)  
32  
Preliminary Information  
MT9076  
6.0 Transmit Data All Ones (TxAO) Operation  
The TxAO (Transmit all ones) pin allows the PRI interface to transmit an all ones signal under hardware control.  
7.0 Data Link Operation  
7.1  
Data Link Operation in E1 mode  
In E1 mode, MT9076 has a user defined 4, 8, 12, 16 or 20 kbit/s data link for transport of maintenance and  
performance monitoring information across the PCM 30 link. This channel functions using the S bits (S ~S )  
a
a4  
a8  
of the PCM 30 timeslot zero non-frame alignment signal (NFAS). Since the NFAS is transmitted every other  
frame - a periodicity of 250 microseconds - the aggregate bit rate is a multiple of 4 kb/s. As there are five S  
a
bits independently available for this data link, the bit rate will be 4, 8, 12, 16 or 20 kb/s, depending on the bits  
selected for the Data Link (DL).  
The S bits used for the DL are selected by setting the appropriate bits, S ~S , to one in the Data Link Select  
a
a4  
a8  
Word (page 01H, address 17H, bits 4-0). Access to the DL is provided by pins TxDLCLK, TxDL, RxDLCLK and  
RxDL, which allow easy interfacing to an external controller.  
Data to be transmit onto the line in the S bit position is clocked in from the TxDL pin (pin 65 in PLCC, pin 47 in  
a
LQFP) with the clock TxDLCLK (pin 64 in PLCC, pin 46 pin LQFP). Although the aggregate clock rate equals  
the bit rate, it has a nominal pulse width of 244 ns, and it clocks in the TxDL as if it were a 2.048 Mb/s data  
stream. The clock can only be active during bit times 4 to 0 of the STBUS frame. The TxDL input signal is  
clocked into the MT9076 by the rising edge of TxDLCLK. If bits are selected to be a part of the DL, all other  
programmed functions for those S bit positions are overridden.  
a
The RxDLCLK signal (pin 39 - PLCC, pin 14 - LQFP) is derived from the receive extracted clock and is aligned  
with the receive data link output RxDL. The HDB3 decoded receive data, at 2.048 Mbit/s, is clocked out of the  
device on pin RxDL (pin 40 in PLCC, pin 15 in LQFP). In order to facilitate the attachment of this data stream to  
a Data Link controller, the clock signal RxDLCLK consists of positive pulses, of nominal width of 244 ns, during  
the S bit cell times that are selected for the data link.This selection is made by programming address 17H of  
a
master control page 01H. No DL data will be lost or repeated when a receive frame slip occurs. See AC  
Electrical Characteristics for timing requirements.  
7.2  
Data Link Operation in T1 mode  
SLC-96 and ESF protocol allow for carrier messages to be embedded in the overhead bit position. The  
MT9076 provides 3 separate means of controlling these data links. See Data Link Control Word - address 12H,  
page 1H.  
The data links (transmit and receive) may be sourced (sunk) from an external controller using dedicated  
pins on the MT9076 in T1 mode (enabled by setting the bit 7 - EDL of the Data link Control Word).  
Bit Oriented Messages may be transmit and received via a dedicated TxBOM register (page 1H,  
address 13H) and a RxBOM (page 3H, address 15H). Transmission is enabled by setting bit 6 - BIOMEn  
in the Data link Control Word. Bit - oriented messages may be periodically interrupted (up to once per  
second) for a duration of up to 100 milliseconds. This is to accommodate bursts of message - oriented  
protocols. See Table 16 for message structure.  
33  
MT9076  
Preliminary Information  
Octet #  
8
7
6
5
4
3
2
1
Content  
1
2
F
S
L
A
P
G
I
01111110  
A
C / R  
EA  
00111000  
or  
00111010  
3
4
T
E
I
EA  
00000001  
C
O
N
T
R
U2  
R
O
L
00000011  
5
G3  
FE  
G3  
FE  
G3  
FE  
G3  
FE  
F
LV  
SE  
LV  
SE  
LV  
SE  
LV  
SE  
C
G4  
LB  
G4  
LB  
G4  
LB  
G4  
LB  
U1  
G1  
U1  
G1  
U1  
G1  
U1  
G1  
G5  
G2  
G5  
G2  
G5  
G2  
G5  
G2  
SL  
G6  
NI  
t0  
t0  
6
Nm  
SL  
7
U2  
R
G6  
NI  
t0-1  
8
Nm  
SL  
t0-1  
9
U2  
R
G6  
NI  
t0-2  
10  
11  
12  
13  
14  
Nm  
SL  
t0-2  
U2  
R
G6  
NI  
t0-3  
Nm  
t0-3  
S
VARIABLE  
Table 16 - Message Oriented Performance Report Structure (T1.403 and T1.408)  
Note:  
ADDRESS  
00111000  
INTERPRETATION  
SAPI = 14, C/R = 0 (CI) EA = 0  
00111010  
00000001  
CONTROL  
SAPI = 14, C/R = 1(Carrier) EA = 0  
TEI = 0, EA =1  
INTERPRETATION  
00000011  
Unacknowledged Information Transfer  
ONE SECOND REPORT  
G1 = 1  
INTERPRETATION  
CRC Error Event =1  
G2 =1  
1 < CRC Error Event < 5  
G3 =1  
5 < CRC Error Event < 10  
10 < CRC Error Event < 100  
100 < CRC Error Event < 319  
CRC Error Event > 320  
G4 =1  
G5 =1  
G6 =1  
SE = 1  
Severely - Errored Framing Event >=1  
Frame Synchronization Bit Error Event >=1  
Line code Violation Event >=1  
Slip Event >=1  
FE = 1  
LV = 1  
SL = 1  
LB = 1  
Payload Loopback Activated  
Under Study for sync.  
U1,U2 = 0  
R = 0  
Reserved - set to 0  
NmNI = 00, 01, 10, 11  
One Second Module 4 counter  
FCS  
INTERPRETATION  
CRC16 Frame Check Sequence  
VARIABLE  
34  
Preliminary Information  
MT9076  
7.2.1  
External Data Link  
In T1 mode, MT9076 has two pairs of pins (TxDL and TxDLCLK, RxDL and RxDLCLK) dedicated to  
transmitting and receiving bits in the selected overhead bit positions. Pins TxDLCLK and RxDLCLK are clock  
outputs available for clocking data into the MT9076 (for transmit) or external device (for receive information).  
Each clock operates at 4 Khz. In the SLC-96 mode the optional serial data link is multiplexed into the Fs bit  
position. In the ESF mode, the serial data link is multiplexed into odd frames, i.e. the FDL bit positions.  
7.2.2  
Bit - Oriented Messaging  
In T1 mode, MT9076 Bit oriented messaging may be selected by setting bit 6 (BIOMEn) in the Data Link  
Control Word (page 1H, address 12H). The transmit data link will contain the repeating serial data stream  
111111110xxxxxx0 where the byte 0xxxxxx0 originates from the user programmed register "Transmit Bit  
Oriented Message" - page 1H address 13H. The receive BIOM register "Receive Bit Oriented Message" - page  
3H, address 15H, will contain the last received valid message (the 0xxxxxx0 portion of the incoming serial bit  
stream). To prevent spurious inputs from creating false messages, a new message must be present in 7 of the  
last 10 appropriate byte positions before being loaded into the receive BIOM register. When a new message  
has been received, a maskable interrupt (maskable by setting bit 1 low in Interrupt Mask Word Three - page  
1H, address 1EH) may occur.  
8.0 Floating HDLC Channels  
MT9076 has three embedded HDLC controllers (HDLC0, HDLC1, HDLC2) each of which includes the following  
features:  
Independent transmit and receive FIFO's;  
Receive FIFO maskable interrupts for nearly full (programmable interrupt levels) and overflow  
conditions;  
Transmit FIFO maskable interrupts for nearly empty (programmable interrupt levels) and underflow  
conditions;  
Maskable interrupts for transmit end-of-packet and receive end-of-packet;  
Maskable interrupts for receive bad-frame (includes frame abort);  
Transmit end-of-packet and frame-abort functions.  
Each controller may be attached to any of the active 64 Kkb/s channels (24 in the case of T1, 31 in the case of  
E1). HDLC0 may also be attached to the FDL in a T1 ESF link by connecting it to phantom channel 31 when  
programming the HDLC Select Word. If HDLC0 is attached to channel 0 in E1 mode, only the activated Sa bits  
(as per the Multiframe and Data Selection Word) will be transmit and received by the controller.  
8.1  
Channel Assignment  
In T1 mode, any DS1 channel can be connected to either of HDLC0,1 or 2, operating at 56 or 64 Kb/s. Setting  
control bit H1R64 (address 12 H on page 01H) high selects 64 Kb/s operation for all HDLCs. Setting this bit low  
selects 56 Kb/s for all HDLC. Interrupts from any of the HDLCs are masked when they are disconnected.  
In E1 mode, all PCM-30 channels except channel 0 can be connected to either of HDLC0,1 or 2. HDLC1 and  
HDLC2 operate at 64 Kb/s. HDLC0 operates at 64 kb/s when connected to any of channels 1 to 31. When  
connected to channel 0 HDLC0 operates at 4, 8, 12, 16 or 20 Kb/s depending on the number of activated Sa  
bits.  
HDLCs can be activated by programming the HDLC Select Words (page 02H, addresses 19H, 1AH and 1BH  
for HDLC0, HDLC1 and HDLC2 respectively).  
35  
MT9076  
Preliminary Information  
8.2  
HDLC Description  
The HDLC handles the bit oriented packetized data transmission as per X.25 level two protocol defined by  
CCITT. It provides flag and abort sequence generation and detection, zero insertion and deletion, and Frame  
Check Sequence (FCS) generation and detection. A single byte, dual byte and all call address in the received  
frame can be recognized. Access to the receive FCS and inhibiting of transmit FCS for terminal adaptation are  
also provided. Each HDLC controller has a 128 byte deep FIFO associated with it. The status and interrupt  
flags are programmable for FIFO depths that can vary from 16 to 128 bytes in steps of 16 bytes. These and  
other features are enabled through the HDLC control registers on page 0BH and 0CH.  
8.2.1  
HDLC Frame structure  
In T1 mode or E1 mode, a valid HDLC frame begins with an opening flag, contains at least 16 bits of address  
and control or information, and ends with a 16 bit FCS followed by a closing flag. Data formatted in this manner  
is also referred to as a “packet”. Refer to Table 17: HDLC Frame Format  
Flag (7E)  
Data Field  
FCS  
Flag (7E)  
One Byte  
01111110  
n Bytes  
n 2  
Two Bytes  
One Byte  
01111110  
Table 17 - HDLC Frame Format  
All HDLC frames start and end with a unique flag sequence “01111110”. The transmitter generates these flags  
and appends them to the packet to be transmitted. The receiver searches the incoming data stream for the  
flags on a bit- by-bit basis to establish frame synchronization.  
The data field consists of an address field, control field and information field. The address field consists of one  
or two bytes directly following the opening flag. The control field consists of one byte directly following the  
address field. The information field immediately follows the control field and consists of N bytes of data. The  
HDLC does not distinguish between the control and information fields and a packet does not need to contain an  
information field to be valid.  
The FCS field, which precedes the closing flag, consists of two bytes. A cyclic redundancy check utilizing the  
16  
12  
5
CRC-CCITT standard generator polynomial “X +X +X +1” produces the 16-bit FCS. In the transmitter the  
FCS is calculated on all bits of the address and data field. The complement of the FCS is transmitted, most  
significant bit first, in the FCS field. The receiver calculates the FCS on the incoming packet address, data and  
FCS field and compares the result to “F0B8”. If no transmission errors are detected and the packet between the  
flags is at least 32 bits in length then the address and data are entered into the receive FIFO minus the FCS  
which is discarded.  
8.2.2  
Data Transparency (Zero Insertion/Deletion)  
Transparency ensures that the contents of a data packet do not imitate a flag, go-ahead, frame abort or idle  
channel. The contents of a transmitted frame, between the flags, is examined on a bit-by-bit basis and a 0 bit is  
inserted after all sequences of 5 contiguous 1 bits (including the last five bits of the FCS). Upon receiving five  
contiguous 1s within a frame the receiver deletes the following 0 bit.  
8.2.3  
Invalid Frames  
A frame is invalid if one of the following four conditions exists (Inserted zeros are not part of a valid count):  
If the FCS pattern generated from the received data does not match the “F0B8” pattern then the last  
data byte of the packet is written to the received FIFO with a ‘bad packet’ indication.  
A short frame exists if there are less than 25 bits between the flags. Short frames are ignored by the  
receiver and nothing is written to the receive FIFO.  
Packets which are at least 25 bits in length but less than 32 bits between the flags are also invalid. In  
this case the data is written to the FIFO but the last byte is tagged with a “bad packet” indication.  
If a frame abort sequence is detected the packet is invalid. Some or all of the current packet will reside  
in the receive FIFO, assuming the packet length before the abort sequence was at least 26 bits long.  
36  
Preliminary Information  
MT9076  
8.2.4  
Frame Abort  
The transmitter will abort a current packet by substituting a zero followed by seven contiguous 1s in place of the  
normal packet. The receiver will abort upon reception of seven contiguous 1s occurring between the flags of a  
packet which contains at least 26 bits.  
Note that should the last received byte before the frame abort end with contiguous 1s, these are included in the  
seven 1s required for a receiver abort. This means that the location of the abort sequence in the receiver may  
occur before the location of the abort sequence in the originally transmitted packet. If this happens then the last  
data written to the receive FIFO will not correspond exactly with the last byte sent before the frame abort.  
8.2.5  
Interframe Time Fill and Link Channel States  
When the HDLC transmitter is not sending packets it will wait in one of two states  
Interframe Time Fill state: This is a continuous series of flags occurring between frames indicating that  
the channel is active but that no data is being sent.  
Idle state: An idle Channel occurs when at least 15 contiguous 1s are transmitted or received.  
In both states the transmitter will exit the wait state when data is loaded into the transmitter FIFO.  
8.2.6  
Go-Ahead  
A go ahead is defined as the pattern "011111110" (contiguous 7Fs) and is the occurance of a frame abort  
sequence followed by a zero, outside of the boundaries of a normal packet. Being able to distinguish a proper  
(in packet) frame abort sequence from one occurring outside of a packet allows a higher level of signaling  
protocol which is not part of the HDLC specifications.  
8.3  
HDLC Functional Description  
The HDLC transceiver can be reset by either the power reset input signal or by the HRST Control bit in the test  
control register (software reset). When reset, the HDLC Control Registers are cleared, resulting in the  
transmitter and receiver being disabled. The Receiver and Transmitter can be enabled independent of one  
another through Control Register 1. The transceiver input and output are enabled when the enable control bits  
in Control Register 1 are set. Transmit to receive loopback as well as a receive to transmit loopback are also  
supported. Transmit and receive bit rates and enables can operate independently. In MT9076 the transceiver  
can operate at a continuous rate independent of RXcen and TXcen (free run mode) by setting the Frun bit of  
Control Register 1.  
Received packets from the serial interface are sectioned into bytes by an HDLC receiver that detects flags,  
checks for go-ahead signals, removes inserted zeros, performs a cyclical redundancy check (CRC) on  
incoming data, and monitors the address if required. Packet reception begins upon detection of an opening  
flag. The resulting bytes are concatenated with two status bits (RQ9, RQ8) and placed in a receiver first-in-first-  
out (Rx FIFO); a buffer register that generates status and interrupts for microprocessor read control.  
In conjunction with the control circuitry, the microprocessor writes data bytes into a Tx buffer register (Tx FIFO)  
that generates status and interrupts. Packet transmission begins when the microprocessor writes a byte to the  
Tx FIFO. Two status bits are added to the Tx FIFO for transmitter control of frame aborts (FA) and end of  
packet (EOP) flags. Packets have flags appended, zeros inserted, and a CRC, also referred to as frame  
checking sequence (FCS), added automatically during serial transmission. When the Tx FIFO is empty and  
finished sending a packet, Interframe Time Fill bytes (continuous flags (7E hex)), or Mark Idle (continuous  
ones) are transmitted to indicate that the channel is idle.  
8.3.1  
HDLC Transmitter  
Following initialization and enabling, the transmitter is in the Idle Channel state (Mark Idle), continuously  
sending ones. Interframe Time Fill state (Flag Idle) is selected by setting the Mark idle bit in Control Register 1  
high. The Transmitter remains in either of these two states until data is written to the Tx FIFO. Control Register  
1 bits EOP (end of packet) and FA (Frame Abort) are set as status bits before the microprocessor loads 8 bits  
of data into the 10 bit wide FIFO (8 bits data and 2 bits status). To change the tag bits being loaded in the FIFO,  
Control Register 1 must be written to before writing to the FIFO. However, EOP and FA are reset after writing to  
37  
MT9076  
Preliminary Information  
the TX FIFO. The Transmit Byte Count Registers may also be used to tag an end of packet. The total packet  
size may be programmed to be up to 65,535 bytes. For a packet length of 1 to 255 bytes it is only necessary to  
write the packet size into the Lower Transmit Byte Count Register. For a packet length of 256 to 65,535 bytes it  
is necessary to write the 16 bit binary count into the Extended Transmit Byte Count Register (MSByte) and the  
Lower Transmit Byte Count Register (LSByte). Note that the order of writing the upper byte before the lower  
byte must be observed even when the lower byte is all zero. Internal registers are loaded with the number of  
bytes in the packet and decremented after every write to the Tx FIFO. When a count of one is reached, the next  
byte written to the FIFO is tagged as an end of packet. The register may be made to cycle through the same  
count if the packets are of the same length by setting Control Register 2 bit Cycle.  
If the transmitter is in the Idle Channel state when data is written to the Tx FIFO, then an opening flag is sent  
and data from Tx FIFO follows. Otherwise, data bytes are transmitted as soon as the current flag byte has been  
sent. Tx FIFO data bytes are continuously transmitted until either the FIFO is empty or an EOP or FA status bit  
is read by the transmitter. After the last bit of the EOP byte has been transmitted, a 16-bit FCS is sent followed  
by a closing flag. When multiple packets of data are loaded into Tx FIFO, only one flag is sent between  
packets.  
Frame aborts (the transmission of 7F hex), are transmitted by tagging a byte previously written to the Tx FIFO.  
When a byte has an FA tag, then an FA is sent instead of that tagged byte. That is, all bytes previous to but not  
including that byte are sent. After a Frame Abort, the transmitter returns to the Mark Idle or Interframe Time Fill  
state, depending on the state of the Mark idle control bit.  
Tx FIFO underrun will occur if the FIFO empties and the last byte did not have either an EOP or FA tag. A  
frame abort sequence will be sent when an underrun occurs.  
Below is an example of the transmission of a three byte packet (’AA’ ’03’ ’77’ hex) (Interframe time fill). TXcen  
can be enabled before or after this sequence.  
(a) Write ’04’hex to Control Register 1  
(b) Write ’AA’ hex to TX FIFO  
(c) Write ’03’hex to TX FIFO  
-Mark idle bit set  
-Data byte  
-Data byte  
(d) Write ’34’hex to Control Register 1  
(e) Write ’77’hex to TX FIFO  
-TXEN; EOP; Mark idle bits set  
-Final data byte  
The transmitter may be enabled independently of the receiver. This is done by setting the TXEN bit of the  
Control Register. Enabling happens immediately upon writing to the register. Disabling using TXen will occur  
after the completion of the transmission of the present packet; the contents of the FIFO are not cleared.  
Disabling will consist of stopping the transmitter clock. The Status and Interrupt Registers may still be read and  
the FIFO and Control Registers may be written to while the transmitter is disabled. The transmitted FCS may  
be inhibited using the Tcrci bit of Control Register 2. In this mode the opening flag followed by the data and  
closing flag is sent and zero insertion still included, but no CRC. That is, the FCS is injected by the  
microprocessor as part of the data field. This is used in V.120 terminal adaptation for synchronous protocol  
sensitive UI frames.  
8.3.2  
HDLC Receiver  
After initialization and enabling, the receiver clocks in serial data, continuously checking for Go-aheads (0 1111  
1110), flags (0111 1110), and Idle Channel states (at least fifteen ones). When a flag is detected, the receiver  
synchronizes itself to the serial stream of data bits, automatically calculating the FCS. If the data length  
between flags after zero removal is less than 25 bits, then the packet is ignored so no bytes are loaded into Rx  
FIFO. When the data length after zero removal is between 25 and 31 bits, a first byte and bad FCS code are  
loaded into the Rx FIFO (see definition of RQ8 and RQ9 below). For an error-free packet, the result in the CRC  
register should match the HEX pattern of’F0B8’ when a closing flag is detected.  
If address recognition is required, the Receiver Address Recognition Registers are loaded with the desired  
address and the Adrec bit in the Control Register 1 is set high. Bit 0 of the Address Registers is used as an  
enable bit for that byte, thus allowing either or both of the first two bytes to be compared to the expected values.  
Bit 0 of the first byte of the address received (address extension bit) will be monitored to determine if a single or  
38  
Preliminary Information  
MT9076  
dual byte address is being received. If this bit is 0 then a two byte address is being received and then only the  
first six bits of the first address byte are compared. An all call condition is also monitored for the second  
address byte; and if received the first address byte is ignored (not compared with mask byte). If the address  
extension bit is a 1 then a single byte address is being received. In this case, an all call condition is monitored  
for in the first byte as well as the mask byte written to the comparison register and the second byte is ignored.  
Seven bits of address comparison can be realized on the first byte if this is a single byte address by setting the  
Seven bit of Control Register 2.  
The following two Status Register bits (RQ8 and RQ9) are appended to each data byte as it is written to the Rx  
FIFO. They indicate that a good packet has been received (good FCS and no frame abort), or a bad packet  
with either incorrect FCS or frame abort. The Status and Interrupt Registers should be read before reading the  
Rx FIFO since status and interrupt information correspond to the byte at the output of the FIFO (i.e. the byte  
about to be read). The Status Register bits are encoded as follows:  
RQ9  
RQ8  
Byte status  
1
0
1
0
1
1
0
0
last byte (bad packet)  
first byte  
last byte (good packet)  
packet byte  
The end-of-packet-detect (EOPD) interrupt indicates that the last byte written to the Rx FIFO was an EOP byte  
(last byte in a packet). The end-of-packet-read (EopR) interrupt indicates that the byte about to be read from  
the Rx FIFO is an EOP byte (last byte in a packet). The Status Register should be read to see if the packet is  
good or bad before the byte is read.  
A minimum size packet has an 8-bit address, an 8-bit control byte, and a 16-bit FCS pattern between the  
opening and closing flags (see Section 9.3.2). Thus, the absence of a data transmission error and a frame  
length of at least 32 bits results in the receiver writing a valid packet code with the EOP byte into Rx FIFO. The  
last 16 bits before the closing flag are regarded as the FCS pattern and will not be transferred to the receiver  
FIFO. Only data bytes (Address, Control, Information) are loaded into the Rx FIFO.  
In the case of an Rx FIFO overflow, no clocking occurs until a new opening flag is received. In other words, the  
remainder of the packet is not clocked into the FIFO. Also, the top byte of the FIFO will not be written over. If  
the FIFO is read before the reception of the next packet then reception of that packet will occur. If two  
beginning of packet conditions (RQ9=0;RQ8=1) are seen in the FIFO, without an intermediate EOP status,  
then overflow occurred for the first packet.  
The receiver may be enabled independently of the transmitter. This is done by setting the RXEN bit of Control  
Register 1. Enabling happens immediately upon writing to the register. Disabling using RXEN will occur after  
the present packet has been completely loaded into the FIFO. Disabling can occur during a packet if no bytes  
have been written to the FIFO yet. Disabling will consist of disabling the internal receive clock. The FIFO,  
Status, and Interrupt Registers may still be read while the receiver is disabled. Note that the receiver requires a  
flag before processing a frame, thus if the receiver is enabled in the middle of an incoming packet it will ignore  
that packet and wait for the next complete one.  
The receive CRC can be monitored in the Rx CRC Registers. These registers contain the actual CRC sent by  
the other transmitter in its original form; that is, MSB first and bits inverted. These registers are updated by  
each end of packet (closing flag) received and therefore should be read when an end of packet is received so  
that the next packet does not overwrite the registers.  
39  
MT9076  
Preliminary Information  
9.0 Slip Buffers  
9.1  
Slip Buffer in T1 Mode  
In T1 mode, MT9076 contains two slip buffers, one on the transmit side, and one on the receive side. Both  
sides may perform a controlled slip. The mechanisms that govern the slip function are a function of backplane  
timing and the mapping between the ST-BUS channels and the DS1 channels. The slip mechanisms are  
different for the transmit and receive slip buffers. The extracted 1.544 Mhz clock (Exclk) and the internally  
generated transmit 1.544 Mhz clock are distinct. Slips on the transmit side are independent from slips on the  
receive side. In IMA mode neither the transmit nor receive slip buffer is activated.  
The transmit slip buffer has data written to it from the near end 2.048 Mb/s stream. The data is clocked out of  
the buffer using signals derived from the transmit 1.544 Mhz clock. The transmit 1.544 Mhz clock is always  
phase locked to the DSTi 2.048 Mb/s stream. If the system 4.096 Mhz clock (C4b) is internally generated (pin  
BS/LS low), then it is hard locked to the 1.544 Mhz clock. No phase drift or wander can exist between the two  
signals - therefore no slips will occur. The delay through the transmit elastic buffer is then fixed, and is a  
function of the relative mapping between the DSTi channels and the DS1 timeslots. These delays vary with the  
position of the channel in the frame. For example, DS1 timeslot 1 sits in the elastic buffer for approximately 1  
usec and DS1 timeslot 24 sits in the elastic buffer for approximately 32 usec.  
0 uS  
Write  
Pointer  
Read Pointer  
4 uS  
92 uS  
Read Pointer  
221 uS  
Wander Tolerance  
512 Bit  
Elastic  
Store  
62 uS  
188 uS  
92 uS  
96 uS  
Read Pointer  
129 uS  
Read Pointer  
Read Vectors  
Minimum Delay  
Frame 0  
Frame 1  
Write Vectors  
Frame 0  
Frame 1  
Frame 1  
Frame 0  
Read Vectors - Maximum Delay  
Figure 12 - Read and Write Pointers in the Transmit Slip Buffers  
If the system 4.096 Mhz clock (C4b) is externally generated (pin BS/LS high), the transmit 1.544 Mhz clock is  
phase locked to it, but the PLL is designed to filter jitter present in the C4b clock. As a result phase drift will  
result between the two signals. The delay through the transmit elastic buffer will vary in accordance with the  
input clock drift, as well as being a function of the relative mapping between the DSTi channels and the DS1  
timeslots. If the read pointers approach the write pointers (to within approximately 1 usec) or the delay through  
the transmit buffer exceeds 218 usecs a controlled slip will occur. The contents of a single frame of DS1 data  
will be skipped or repeated; a maskable interrupt (masked by setting bit 1 - TxSLPI high in Interrupt Mask Word  
Zero - page 1H, address 1bH) will be generated, and the status bit TSLIP (page 3H, address 17H) of MSB  
Transmit Slip Buffer register will toggle. The direction of the slip is indicated by bit 6 of the same register  
(TSLPD). The relative phase delay between the system frame boundary and the transmit elastic frame read  
40  
Preliminary Information  
MT9076  
boundary is measured every frame and reported in the Transmit Slip Buffer Delay register- (page 3H, address  
17H). In addition the relative offset between these frame boundaries may be programmed by writing to this  
register. Every write to Transmit Elastic Buffer Set Delay Word resets the transmit elastic frame count bit  
TxSBMSB (address 17H, page 3H). After a write the delay through the slip buffer is less than 1 frame in  
duration. Each write operation will result in a disturbance of the transmit DS1 frame boundary, causing the far  
end to go out of sync. Writing BC (hex) into the TxSBDLY register maximizes the wander tolerance before a  
controlled slip occurs. Under normal operation no slips should occur in the transmit path. Slips will only occur if  
the input C4b clock has excess wander, or the Transmit Elastic Buffer Set Delay Word register is initialized too  
close to the slip pointers after system initialization.  
The two frame receive elastic buffer is attached between the 1.544 Mbit/s DS1 receive side and the 2.048 Mbit/  
s ST-BUS side of the MT9076. Besides performing rate conversion, this elastic buffer is configured as a slip  
buffer which absorbs wander and low frequency jitter in multi-trunk applications. The received DS1 data is  
clocked into the slip buffer with the Exclk clock and is clocked out of the slip buffer with the system C4b clock.  
The Exclk extracted clock is generated from, and is therefore phase-locked with, the receive DS1 data. In the  
case of Internal mode (pin BS/LS set low) operation, the Exclk clock may be phase-locked to the C4b clock by  
an internal phase locked loop (PLL). Therefore, in a single trunk system the receive data is in phase with the  
Exclk clock, the C4b clock is phase locked to the E1.5o clock, and the read and write positions of the slip buffer  
track each other.  
In a multi-trunk slave or loop-timed system (i.e., PABX application) a single trunk will be chosen as a network  
synchronizer, which will function as described in the previous paragraph. The remaining trunks will use the  
system timing derived from the synchronizer to clock data out of their slip buffers. Even though the DS1 signals  
from the network are synchronous to each other, due to multiplexing, transmission impairments and route  
diversity, these signals may jitter or wander with respect to the synchronizing trunk signal. Therefore, the Exclk  
clocks of non-synchronized trunks may wander with respect to the Exclk clock of the synchronizer and the  
system bus. Network standards state that, within limits, trunk interfaces must be able to receive error-free data  
in the presence of jitter and wander (refer to network requirements for jitter and wander tolerance). The  
MT9076 will allow 92 usec (140 UI, DS1 unit intervals) of wander and low frequency jitter before a frame slip  
will occur.  
When the C4b and the Exclk clocks are not phase-locked, the rate at which data is being written into the slip  
buffer from the DS1 side may differ from the rate at which it is being read out onto the ST-BUS. If this situation  
persists, the delay limits stated in the previous paragraph will be violated and the slip buffer will perform a  
controlled frame slip. That is, the buffer pointers will be automatically adjusted so that a full DS1 frame is either  
repeated or lost. All frame slips occur on frame boundaries.  
The minimum delay through the receive slip buffer is approximately 1 usec and the maximum delay is  
approximately 249 uS. Figure 14 illustrates the relationship between the read and write pointers of the receive  
slip buffer (contiguous time slot mapping). Measuring clockwise from the write pointer, if the read page pointer  
comes within 8 usec of the write page pointer a frame slip will occur, which will put the read page pointer 157  
usec from the write page pointer. Conversely, if the read page pointer moves more than 249 usec from the write  
page pointer, a slip will occur, which will put the read page pointer 124 usec from the write page pointer. This  
provides a worst case hysteresis of 92 usec peak = 142 U.I.  
41  
MT9076  
Preliminary Information  
0 uS  
Write  
Pointer  
Read Pointer  
4 uS  
92 uS  
Read Pointer  
221 uS  
Wander Tolerance  
512 Bit  
Elastic  
Store  
62 uS  
188 uS  
92 uS  
96 uS  
Read Pointer  
129 uS  
Read Pointer  
Read Vectors  
Minimum Delay  
Frame 0  
Frame 1  
Write Vectors  
Frame 0  
Frame 1  
Frame 1  
Frame 0  
Read Vectors - Maximum Delay  
Figure 13 - Read and Write Pointers in the Transmit Slip Buffers  
The RSLIP and RSLPD status bits (page 3H, address 13H, bits 7 and 6 respectively) give indication of a  
receive slip occurance and direction. A maskable interrupt RxSLPI (page 1H, address 1BH, bit 0 - set high to  
mask) is also provided. RSLIP changes state in the event of a slip. If RSLPD=0, the slip buffer has overflowed  
and a frame was lost; if RSLPD=1, a underflow condition occurred and a frame was repeated.  
9.2  
Slip Buffer in E1 mode  
In E1 mode, in addition to the elastic buffer in the jitter attenuator(JA), another elastic buffer (two frames deep)  
is present, attached between the receive side and the ST-BUS side of the MT9076. This elastic buffer is  
configured as a slip buffer which absorbs wander and low frequency jitter in multi-trunk applications. The  
received PCM 30 data is clocked into the slip buffer with the Exclk clock and is clocked out of the slip buffer with  
the C4b clock. The Exclk extracted clock is generated from, and is therefore phase-locked with, the receive  
PCM 30 data. In normal operation, the C4b clock will be phase-locked to the Exclk clock by a phase locked loop  
(PLL). Therefore, in a single trunk system the receive data is in phase with the Exclk clock, the C4b clock is  
phase-locked to the Exclk clock, and the read and write positions of the slip buffer will remain fixed with respect  
to each other.  
In a multi-trunk slave or loop-timed system (i.e., PABX application) a single trunk will be chosen as a network  
synchronizer, which will function as described in the previous paragraph. The remaining trunks will use the  
system timing derived from the synchronizer to clock data out of their slip buffers. Even though the PCM 30  
signals from the network are synchronous to each other, due to multiplexing, transmission impairments and  
route diversity, these signals may jitter or wander with respect to the synchronizing trunk signal. Therefore, the  
Exclk clocks of non-synchronizer trunks may wander with respect to the Exclk clock of the synchronizer and the  
system bus.  
Network standards state that, within limits, trunk interfaces must be able to receive error-free data in the  
presence of jitter and wander (refer to network requirements for jitter and wander tolerance). The MT9076 will  
allow a maximum of 26 channels (208 UI, unit intervals) of wander and low frequency jitter before a frame slip  
will occur.  
42  
Preliminary Information  
MT9076  
The minimum delay through the receive slip buffer is approximately two channels and the maximum delay is  
approximately 60 channels (see Figure 14).  
When the C4b and the Exclk clocks are not phase-locked, the rate at which data is being written into the slip  
buffer from the PCM 30 side may differ from the rate at which it is being read out onto the ST-BUS. If this  
situation persists, the delay limits stated in the previous paragraph will be violated and the slip buffer will  
perform a controlled frame slip. That is, the buffer pointers will be automatically adjusted so that a full PCM 30  
frame is either repeated or lost. All frame slips occur on PCM 30 frame boundaries.  
Two status bits, RSLIP and RSLPD (page03H, address13H) give indication of a slip occurance and direction.  
RSLIP changes state in the event of a slip. If RSLPD=0, the slip buffer has overflowed and a frame was lost; if  
RSLPD=1, a underflow condition occurred and a frame was repeated. A maskable interrupt SLPI (page 01H,  
address 1BH) is also provided.  
Figure 14 illustrates the relationship between the read and write pointers of the receive slip buffer. Measuring  
clockwise from the write pointer, if the read pointer comes within two channels of the write pointer a frame slip  
will occur, which will put the read pointer 34 channels from the write pointer. Conversely, if the read pointer  
moves more than 60 channels from the write pointer, a slip will occur, which will put the read pointer 28  
channels from the write pointer. This provides a worst case hysteresis of 13 channels peak (26 channels peak-  
to-peak) or a wander tolerance of 208 UI.  
Write  
Pointer  
Read Pointer  
Read Pointer  
60 CH  
13 CH  
2 CH  
Wander Tolerance  
512 Bit  
Elastic  
Store  
15 CH  
47 CH  
-13 CH  
34 CH  
28 CH  
Read Pointer  
Read Pointer  
Figure 14 - Read and Write Pointers in the Slip Buffers  
10.0 Framing Algorithm  
10.1  
Frame Alignment in T1 Mode  
In T1 mode, MT9076 will synchronize to DS1 lines formatted with either the D4 or ESF protocol. In either mode  
the framer maintains a running 3 bit history of received data for each of the candidate bit positions. Candidate  
bit positions whose incoming patterns fail to match the predicted pattern (based on the 3 bit history) are  
winnowed out. If, after a 10 bit history has been examined, only one candidate bit position remains within the  
framing bit period, the receive side timebase is forced to align to that bit position. If no candidates remain after  
a 10 bit history, the process is re-initiated. If multiple candidates exist after a 24 bit history timeout period, the  
framer forces the receive side timebase to synchronize to the next incoming valid candidate bit position. In the  
event of a reframe, the framer starts searching at the next bit position over. This prevents persistent locking to  
a mimic as the controller may initiate a software controlled reframe in the event of locking to a mimic.  
Under software control the framing criteria may be tuned (see Framing Mode Select Register, page 1H,  
address 10H). Selecting D4 framing invites a further decision whether or not to include a cross check of Fs bits  
along with the Ft bits. If Fs bits are checked (by setting control bit CXC high - bit 5 of the Framing Mode Select  
43  
MT9076  
Preliminary Information  
Word, page 1H, address 10H), multiframe alignment is forced at the same time as terminal frame alignment. If  
only Ft bits are checked, multiframe alignment is forced separately, upon detection of the Fs bit history of  
00111 (for normal D4 trunks) or 000111000111 (for SLC-96 trunks). For D4 trunks, a reframe on the multiframe  
alignment may be forced at any time without affecting terminal frame alignment.  
In ESF mode, the circuit will optionally confirm the CRC-6 bits before forcing a new frame alignment. This is  
programmed by setting control bit CXC high (bit 5 of the Framing Mode Select Word, page 1H, address 10H). A  
CRC-6 confirmation adds a minimum of 6 milliseconds to the reframe time. If no CRC-6 match is found after 16  
attempts, the framer moves to the next valid candidate bit position (assuming other bit positions contain a  
match to the framing pattern) or re-initiates the whole framing procedure (assuming no bit positions have been  
found to match the framing pattern).  
The framing circuit is off - line. During a reframe, the rest of the circuit operates synchronous with the last frame  
alignment. Until such time as a new frame alignment is achieved, the signaling bits are frozen in their states at  
the time that frame alignment was lost, and error counting for Ft, Fs, ESF framing pattern or CRC-6 bits is  
suspended.  
10.2  
Frame Alignment in E1 mode  
In E1 mode, MT9076 contains three distinct framing algorithms: basic frame alignment, signaling multiframe  
alignment and CRC-4 multiframe alignment. Figure 16 is a state diagram that illustrates these algorithms and  
how they interact.  
After power-up, the basic frame alignment framer will search for a frame alignment signal (FAS) in the PCM 30  
receive bit stream. Once the FAS is detected, the corresponding bit 2 of the non-frame alignment signal (NFAS)  
is checked. If bit 2 of the NFAS is zero a new search for basic frame alignment is initiated. If bit 2 of the NFAS  
is one and the next FAS is correct, the algorithm declares that basic frame synchronization has been found  
(i.e., page 03H, address 10H, bit 7, SYNC is zero).  
Once basic frame alignment is acquired the signaling and CRC-4 multiframe searches will be initiated. The  
signaling multiframe algorithm will align to the first multiframe alignment signal pattern (MFAS = 0000) it  
receives in the most significant nibble of channel 16 (page 3, address 10H, bit 6, MFSYNC = 0). signaling  
multiframing will be lost when two consecutive multiframes are received in error.  
The CRC-4 multiframe alignment signal is a 001011 bit sequence that appears in PCM 30 bit position one of  
the NFAS in frames 1, 3, 5, 7, 9 and 11 (see Table 11). In order to achieve CRC-4 synchronization two  
consecutive CRC-4 multiframe alignment signals must be received without error (page 03H, address 10H  
CRCSYN = 0).  
The E1 framing algorithm supports automatic interworking of interfaces with and without CRC-4 processing  
capabilities. That is, if an interface with CRC-4 capability, achieves valid basic frame alignment, but does not  
achieve CRC-4 multiframe alignment by the end of a predefined period, the distant end is considered to be a  
non-CRC-4 interface. When the distant end is a non-CRC-4 interface, the near end automatically suspends  
receive CRC-4 functions, continues to transmit CRC-4 data to the distant end with its E-bits set to zero, and  
provides a status indication. Naturally, if the distant end initially achieves CRC-4 synchronization, CRC-4  
processing will be carried out by both ends. This feature is selected when control bit AUTC (page 01H, address  
10H) is set to zero.  
44  
Preliminary Information  
MT9076  
Out of synchronization  
YES  
NO  
Search for primary basic frame  
alignment signal RAI=1, Es=0.  
3 consecutive  
incorrect frame  
alignment  
signals  
YES  
>914 CRC errors  
in one second  
NO  
Verify Bit 2 of non-frame  
alignment signal.  
YES  
NO  
Verify second occurrence of  
frame alignment signal.  
No CRC  
multiframe alignment.  
8 msec. timer expired*  
YES  
Primary basic frame synchronization  
acquired. Enable traffic RAI=0, E’s=0. Start  
loss of primary basic frame alignment  
checking. Notes 7 & 8.  
CRC-4 multi-frame alignment  
Signalling multi-frame alignment  
Search for multiframe  
alignment signal.  
Start 400 msec timer.  
Note 7.  
Note 7.  
YES  
NO  
RAI = 0  
Multiframe synchronization  
acquired as per G.732.  
Note 7.  
Start 8 msec timer.  
Note 7.  
Basic frame  
alignment acquired  
NO  
YES  
Find two CRC frame  
alignment signals.  
Note 7.  
No CRC  
Check for two consecutive errored  
multiframe alignment signals.  
multiframe  
alignment.  
Notes 7 & 8.  
8 msec.  
timer expired**  
CRC multiframe  
alignment  
CRC-to-CRC interworking. Re-align to new basic  
Parallel search for new basic frame  
alignment signal.  
frame alignment. Start CRC-4 processing. E-bits set  
as per G.704 and I.431. Indicate CRC synchronization  
achieved.  
Notes 6 & 7.  
Notes 7& 8.  
400 msec timer expired  
CRC-to-non-CRC interworking. Maintain primary  
basic frame alignment. Continue to send CRC-4  
data, but stop CRC processing. E-bits set to ‘0’.  
Indicate CRC-to-non-CRC operation. Note 7.  
*
only if CRC-4 synchronization is selected and automatic CRC-4  
interworking is de-selected.  
** only if automatic CRC-4 interworking is selected.  
Figure 15 - Synchronization State Diagram  
45  
MT9076  
Preliminary Information  
10.2.1 Notes for Synchronization State Diagram (Figure 16)  
1) The basic frame alignment, signaling multiframe alignment, and CRC-4 multiframe alignment functions  
operate in parallel and are independent.  
2) The receive channel associated signaling bits and signaling multiframe alignment bit will be frozen when  
multiframe alignment is lost.  
3) Manual re-framing of the receive basic frame alignment and signaling multiframe alignment functions can be  
performed at any time.  
4) The transmit RAI bit will be one until basic frame alignment is established, then it will be zero.  
5) E-bits can be optionally set to zero until the equipment interworking relationship is established. When this  
has been determined one of the following will take place:  
a) CRC-to-non-CRC operation - E-bits = 0,  
b) CRC-to-CRC operation - E-bits as per G.704 and I.431.  
6) All manual re-frames and new basic frame alignment searches start after the current frame alignment signal  
position.  
7) After basic frame alignment has been achieved, loss of frame alignment will occur any time three  
consecutive incorrect basic frame alignment signals are received. Loss of basic frame alignment will reset  
the complete framing algorithm.  
8) When CRC-4 multiframing has been achieved, the primary basic frame alignment and resulting multiframe  
alignment will be adjusted to the basic frame alignment determined during CRC-4 synchronization.  
Therefore, the primary basic frame alignment will not be updated during the CRC-4 multiframing search, but  
will be updated when the CRC-4 multiframing search is complete.  
10.3  
Reframe  
10.3.1 E1 Mode  
The MT9076 will automatically force a reframe, if three consecutive frame alignment patterns or three  
consecutive non-frame alignment bits are in error.  
10.3.2 T1 Mode  
The MT9076 will automatically force a reframe if the framing bit error density exceeds the threshold  
programmed by control bits RS1-0 (Framing Mode Select Word page 1H, address 10H). RS1 = RS0 = 0 forces  
a reframe for 2 errors out of a sliding window of 4 framing bits. RS1 = 0, RS0 = 1 forces a reframe with 2 errors  
out of 5. RS1 = 1, RS0 = 0 forces a reframe with 2 errors out of 6. RS1 = RS0 = 1 disables the automatic  
reframe.  
In ESF mode, all framing bits are checked. In D4 mode, either Ft bits only (if control bit 2 - FSI - of Framing  
Mode Select Register is set low) or Ft and Fs bits are checked (FSI set high). If the D4 secondary yellow alarm  
is enabled (control bit 1 - D4SECY of Transmit Alarm Control Word page 1H, address 11H) then the Fs bit of  
frame 12 is not verified for the loss of frame circuit.  
In E1 or T1 mode, receive transparent mode (selected when bit 3 page 1 address 12H is high) no reframing is  
forced by the device.  
The user may initiate a software reframe at any time by setting bit 1, page 1, address 10H high (ReFR). Once  
the circuit has commenced reframing the signaling bits are frozen until multiframe synchronization has been  
achieved.  
11.0 MT9076 Channel Signaling  
11.1  
Channel Signaling in T1 Mode  
In T1 mode, when control bit RBEn (page 1H, address 14H) is low the MT9076 will insert ABCD or AB  
signaling bits into bit 8 of every transmit DS0 channel every 6th frame. The AB or ABCD signaling bits from  
received frames 6 and 12 (AB) or from frames 6, 12, 18 and 24 (ABCD) will be loaded into an internal storage  
46  
Preliminary Information  
MT9076  
ram. The transmit AB/ ABCD signaling nibbles can be passed either via the micro-ports (for channels with bit 1  
set high in the Per Time Slot Control Word - pages 7H and 8H) or through related channels of the CSTi serial  
links, see “ST-BUS vs. DS1 to Channel Relationship(T1)” on page 25. The receive signaling bits are always  
mapped to the equivalent ST-BUS channels on CSTo. Memory pages five and six contain the transmit AB or  
ABCD nibbles and pages eight and nine the receive AB or ABCD nibbles for micro-port CAS access.  
The serial control streams that contain the transmit / receive signaling information (CSTi and CSTo  
respectively) are clocked at 2.048 Mhz. The number of signaling bits to be transmit / received = 24 (timeslots)  
x 4 bits per timeslot (ABCD) = 24 nibbles. This leaves many unused nibble positions in the 2.048 Mhz CSTi /  
CSTo bandwidth. These unused nibble locations are tristated. The usage of the bit stream is as follows: the  
signaling bits are inserted / reported in the same CSTi / CSTo channels that correspond to the DS1 channels  
used in DSTi / DSTo - see Table 6, “ST-BUS vs. DS1 to Channel Relationship(T1),on page 25. The control bit  
MSN (signaling Control Word, page 01H, address 14H) allows for the ABCD bit to use the most significant  
nibble of CSTi / CSTo (MSN set high) or the least significant nibble (MSN set low). Unused nibbles and  
timeslots are tristate. In order to facilitate multiplexing on the CSTo control stream, an additional control bit  
CSToEn (signaling Control Word, page 01H, address 14H) will tristate the whole stream when set low. This  
control bit is forced low with the reset pin. In the case of D4 trunks, only AB bits are reported. The control bits  
SM1-0 allow the user to program the 2 unused bits reported on CSTo in the signaling nibble otherwise occupied  
by CD signaling bits in ESF trunks.  
A receive signaling bit debounce of 6 msec. can be selected (DBEn set high - signaling Control Word, page  
01H, address 14H). It should be noted that there may be as much as 3 msec. added to this duration because  
signaling equipment state changes are not synchronous with the D4 or ESF multiframe.  
If multi - frame synchronization is lost (page 3H, address 10H, bit 6 MFSYNC = 1) all receive signaling bits are  
frozen. They will become unfrozen when multi - frame synchronization is acquired (this is the same as terminal  
frame synchronization for ESF links).  
When the SIGI interrupt is unmasked, IRQ will become active when a signaling state change is detected in any  
of the 24 receive channels. The SIGI interrupt mask is located on page 1, address 1EH, bit 0 (set high to  
enable interrupt); and the SIGI interrupt vector is located on page 4, address 1EH.  
11.2  
Channel Signaling in E1 Mode  
In E1 mode, when control bit TxCCS is set to one, the MT9076 is in Common Channel signaling (CCS) mode.  
When TxCCS is low it is in Channel Associated signaling mode (CAS). The CAS mode ABCD signaling nibbles  
can be passed either via the micro-ports (when RPSIG = 1) or through related channels of the CSTo and CSTi  
serial links (when RPSIG = 0). Memory pages 09H and 0AH contain the receive ABCD nibbles and pages 05H  
and 06H the transmit ABCD nibbles for micro-port CAS access.  
In CAS operation, an ABCD signaling bit debounce of 14 msec. can be selected by writing a one to DBNCE  
control bit. This is consistent with the signaling recognition time of ITU-T Q.422. It should be noted that there  
may be as much as 2 msec. added to this duration because signaling equipment state changes are not  
synchronous with the PCM 30 multiframe.  
If multiframe synchronization is lost (page 03H, address 10H, when MFSYNC = 1) all receive CAS signaling  
nibbles are frozen. Receive CAS nibbles will become unfrozen when multiframe synchronization is acquired.  
When the CAS signaling interrupt is unmasked (page 01H, address 1EH, SIGI=0), pin IRQ (pin 12 in PLCC, 65  
in LQFP) will become active when a signaling nibble state change is detected in any of the 30 receive  
channels.  
In CCS mode, the data transmit on channel 16 is either sourced from channel 16 data on DSTi or from the pin  
CSTi. Data received from channel 16 is clocked out on CSTo (pin 5 in PLCC, pin 55 in LQFP). By dividing down  
the extracted 2.048 MHz clock.  
47  
MT9076  
Preliminary Information  
12.0 Loopbacks  
In order to meet PRI Layer 1 requirements and to assist in circuit fault sectioning, the MT9076 has six loopback  
functions. These are as follows:  
a) Digital loopback (DSTi to DSTo at the framer/LIU interface). Bit DLBK = 0 normal; DLBK = 1 activate.  
MT9076  
DSTi  
System  
DSTo  
Tx  
Line  
b) Remote loopback (RTIP and RRING to TTIP and TRING respectively at the Line side). Bit RLBK = 0 normal;  
RLBK = 1 activate.  
MT9076  
Tx  
Line  
Rx  
System  
DSTo  
c) ST-BUS loopback (DSTi to DSTo at the system side). Bit SLBK = 0 normal; SLBK = 1 activate.  
MT9076  
Tx  
Line  
DSTi  
System  
DSTo  
d) Payload loopback (RTIP and RRING to TTIP and TRING respectively at the system side). Bit PLBK = 0  
normal; PLBK = 1 activate. The payload loopback is effectively a physical connection of DSTo to DSTi  
within the MT9076. Sbit information and the DL originate at the point of loopback.  
MT9076  
DSTi  
System  
DSTo  
Tx  
Rx  
Line  
e) Metallic Loopback. MLBK = 0 normal; MLBK = 1 activate, will isolate the external signals RTIP and RRING  
from the receiver and internally connect the analog output TTIP and TRING to the receiver analog input.  
MT9076  
DSTi  
System  
DSTo  
Tx  
Rx  
Line  
f) Per time slot local and remote loopback. Remote time slot loopback control bit RTSL = 0 normal; RTSL = 1  
activate, will loop around transmit ST-BUS time slots to the DSTo stream. Local time slot loopback bits LTSL  
= 0 normal; LTSL = 1 activate, will loop around receive PCM 30 time slots towards the remote PCM 30 end.  
MT9076  
Tx  
Line  
Rx  
DSTi  
System  
DSTo  
The digital, remote, ST-BUS, payload and metallic loopbacks are located on page 1, address 15H - Coding and  
Loopback Control Word. The remote and local time slot loopbacks are controlled through control bits 5 and 4 of  
the Per Time Slot Control Words, pages 7H and 8H.  
48  
Preliminary Information  
MT9076  
13.0 Performance Monitoring  
13.1  
Error Counters  
In T1 mode, MT9076 has eight error counters, which can be used for maintenance testing and ongoing  
measurement of the quality of a DS1 link and to assist the designer in meeting specifications such as TR62411  
and T1.403. All counters can be preset or cleared by writing to the appropriate locations.  
Associated with each counter is a maskable event occurance interrupt and a maskable counter overflow  
interrupt. Overflow interrupts are useful when cumulative error counts are being recorded. For example, every  
time the framing bit error counter overflow interrupt (FERO) occurs, 256 frame errors have been received since  
the last FERO (page 04H, address 1DH)interrupt. All counters are cleared and held low by programming the  
counter clear bit -CNTCLR - high (bit 4 of the Reset Control Word, page 1H, address 1AH). An alternative  
approach to event reporting is to mask error events and to enable the 1 second sample bit (SAMPLE - bit 3 of  
the Reset Control Word). When this bit is set the counters for change of frame alignment, loss of frame  
alignment, line code violation errors, crc errors, errored framing bits, and multiframes out of sync are updated  
on one second intervals coincident with the maskable one second interrupt timer.  
In E1 mode, MT9076 has six error counters, which can be used for maintenance testing, and ongoing  
measurement of the quality of a PCM 30 link and to assist the designer in meeting specifications such as ITU-  
T I.431 and G.821. All counters can be preset or cleared by writing to the appropriate locations.  
Associated with each counter is a maskable event occurance interrupt and a maskable counter overflow  
interrupt. Overflow interrupts are useful when cumulative error counts are being recorded. For example, every  
time the frame error counter overflow (FERO) interrupt occurs, 256 frame errors have been received since the  
last FERO interrupt. All counters are cleared and held low by programming the counter clear bit (master control  
page 01H, address 1A, bit 4) high. Counter overflows set bits in the counter overflow latch (page 04H, address  
1FH); this latch is cleared when read.  
The overflow reporting latch (page 04H, address 1FH) contains a register whose bits are set when individual  
counters overflow. These bits stay high until the register is read.  
13.2  
T1 Counters  
13.2.1 Framing Bit Error Counter (FC7-0)  
This eight bit counter counts errors in the framing pattern. In ESF mode, any error in the 001011 framing  
pattern increments the counter. In SLC-96 mode any error in the Ft bit position is counted. In D4 mode Ft errors  
are always counted, Fs bits (except for the Sbit in frame 12) may optionally be counted (if control bit FSI is set  
high - page 1H, address 10H, bit 2). The counter is located on page 4H, address 13H.  
There are two maskable interrupts associated with the Framing bit error measurement. A single error may  
generate an interrupt (enable by setting FERI high - bit 7 of the Interrupt Mask Word One, page 1H, address  
1CH). A counter overflow interrupt may be enabled by setting control bit FEOM high - bit 2 of Interrupt Mask  
Word Two (page 1H, address 1DH).  
13.2.2 Out Of Frame / Change Of Frame Alignment Counter (OOF3-0/COFA3-0)  
This register space is shared by two nibbles. One is the count of out of frame events. The other independent  
counter is incremented when, after a resynchronization, the frame alignment has moved. This count is reported  
in page 4, address 13H.  
There are two interrupts associated with the Change of Frame Alignment counter. A single error may generate  
an interrupt (enable by setting COFAI high - bit 4 of the Interrupt Mask Word One, page 1H, address 1CH). A  
counter overflow interrupt may be enabled by setting control bit COFAO high - bit 4 of Interrupt Mask Word Two  
(page 1H, address 1DH).  
49  
MT9076  
Preliminary Information  
There is one interrupt associated with the Out of Frame counter. A counter overflow interrupt may be enabled  
by setting control bit OOFO high - bit 5 of Interrupt Mask Word Two (page 1H, address 1DH).  
13.2.3 Multiframes out of Sync Counter (MFOOF7-MFOOF0)  
This eight bit counter MFOOF7 - MFOOF0 is located on page 4 address 15H, and is incremented once per  
multiframe (1.5 ms for D4 and 3 ms for ESF) during the time that the framer is out of terminal frame  
synchronization.  
There is a maskable interrupt associated with the measurement. A counter overflow interrupt may be enabled  
by setting control bit MFOOFO high - bit 1 of Interrupt Mask Word Two (page 1H, address 1DH).  
13.2.4 CRC-6 Error Counter (CC15-0)  
CRC-6 errors are recorded by this counter for ESF links. This 16 bit counter is located on page 4, addresses  
18H and 19H.  
There are two maskable interrupts associated with the CRC error measurement. A single error may generate  
an interrupt (enable by setting CRCI high - bit 6 of the Interrupt Mask Word One, page 1H, address 1CH). A  
counter overflow interrupt may be enabled by setting control bit CRCO high - bit 6 of Interrupt Mask Word Two  
(page 1H, address 1DH).  
13.2.5 Line Code Violation Error Counter (LCV15-LCV0)  
If the control bit EXZ (page 1 address 12H bit 5) is set low, the line code violation error counter will count  
bipolar violations that are not part of B8ZS encoding. If the control bit EXZ (page 1 address 12H bit 5) is set  
high, the line code violation error counter will count both bipolar violations that are not part of B8ZS encoding  
and each occurance of excess zeros (more than 7 successive zeros in a received B8ZS encoded data stream  
and more than 15 successive zeros in a non-B8ZS encoded stream). This counter LCV15-LCV0 is 16 bits long  
(page 4H, addresses 16H and 17H) and is incremented once for every line code violation received. It should be  
noted that when presetting or clearing the LCV error counter, the least significant LCV counter address should  
be written to before the most significant location. This counter will suspend operation when terminal frame  
synchronization is lost if the control bit OOFP is set (bit 2, address 1AH - Reset Control Word).  
There are two maskable interrupts associated with the line code violation error measurement. A single error  
may generate an interrupt (enable by setting LCVI high - bit 3 of the Interrupt Mask Word One, page 1H,  
address 1CH). A counter overflow interrupt may be enabled by setting control bit LCVO high - bit 3 of Interrupt  
Mask Word Two (page 1H, address 1DH).  
13.2.6 PRBS Error Counter (PS7-0)  
There are two 8 bit counters associated with PRBS comparison; one for errors and one for time. Any errors that  
are detected in the receive PRBS will increment the PRBS Error Rate Counter of page 04H, address 10H.  
Writes to this counter will clear an 8 bit counter, PSM7-0 (page 01H, address 11H) which counts receive CRC  
multiframes. A maskable PRBS counter overflow (PRBSO) interrupt (page 1, address 1DH) is associated with  
this counter.  
13.2.7 CRC Multiframe Counter for PRBS (PSM7-0)  
This eight bit counter counts receive CRC multiframes. It can be directly loaded via the microport. The counter  
will also be automatically cleared in the event that the PRBS error counter is written to by the microport. This  
counter is located on page 04H, address 11H.  
13.3  
13.4  
E1 Counters  
Errored FAS Counter (EFAS7-EFAS0)  
An eight bit Frame Alignment Signal Error counter EFAS7 - EFAS0 is located on page 04H address 13H, and is  
incremented once for every receive frame alignment signal that contains one or more errors.  
50  
Preliminary Information  
MT9076  
There are two maskable interrupts associated with the frame alignment signal error measurement. FERI (page  
01H, address 1CH) is initiated when the least significant bit of the errored frame alignment signal counter  
toggles, and FERRO (page 01H, address 1DH) is initiated when the counter changes from FFH to 00H.  
13.5  
E-bit Counter (EC15-0)  
E-bit errors are counted by the MT9076 in order to support compliance with ITU-T requirements. This sixteen  
bit counter is located on page 04H, addresses 14H and 15H respectively. It is incremented by single error  
events, with a maximum rate of twice per CRC-4 multiframe.  
There are two maskable interrupts associated with the E-bit error measurement. EBI (page 1, address 1CH) is  
initiated when the least significant bit of the counter toggles, and FEBEO (page 01H, address 1DH) is initiated  
when the counter overflows.  
13.6  
Line Code Violation Error Counter (LCV15-LCV0)  
If the control bit EXZ (page 1 address 12H bit 5) is set low, the line code violation error counter will count  
bipolar violations that are not part of HDB3 encoding. If the control bit EXZ (page 1 address 12H bit 5) is set  
high, the line code violation error counter will count both bipolar violations that are not part of HDB3 encoding  
and each occurance of excess zeros (more than 3 successive zeros in a received HDB3 encoded data stream  
and more than 15 successive zeros in a non-HDB3 encoded stream). This counter LCV15-LCV0 is 16 bits long  
(page 4H, addresses 16H and 17H) and is incremented once for every line code violation received. It should be  
noted that when presetting or clearing the LCV error counter, the least significant LCV counter address should  
be written to before the most significant location. This counter will suspend operation when terminal frame  
synchronization is lost if the control bit OOFP is set (bit 2, address 1AH - Reset Control Word).  
In E1 mode, there are two maskable interrupts associated with the line code violation error measurement. LCVI  
(page 01H, address 1CH) is initiated when the l significant bit of the LCV error counter toggles. LCVO (page  
01H, address 1DH) is initiated when the counter changes from FFFFH to 0000H.  
13.7  
CRC-4 Error Counter (CC15-0)  
CRC-4 errors are counted by the MT9076 in order to support compliance with ITU-T requirements. This sixteen  
bit counter is located on page 04H, addresses 18H and 19H in E1 mode. It is incremented by single error  
events, which is a maximum rate of twice per CRC-4 multiframe.  
There is a maskable interrupt associated with the CRC error measurement. CRCIM (page 01H, address 1CH)  
is initiated when the least significant bit of the counter toggles, and CRCOM (page 01H, address 1DH) is  
initiated when the counter overflows.  
13.8  
PRBS Error Counter (PS7-0)  
There are two 8 bit counters associated with PRBS comparison; one for errors and one for time. Any errors that  
are detected in the receive PRBS will increment the PRBS Error Rate Counter of page 04H, address 10H.  
Writes to this counter will clear an 8 bit counter, PSM7-0 (page 01H, address 11H) which counts receive CRC  
multiframes. A maskable PRBS counter overflow (PRBSO) interrupt (page 1, address 1DH) is associated with  
this counter.  
13.9  
CRC Multiframe Counter for PRBS (PSM7-0)  
This eight bit counter counts receive CRC-4 multiframes. It can be directly loaded via the microport. The  
counter will also be automatically cleared in the event that the PRBS error counter is written to by the  
microport. This counter is located on page 04H, address 11H.  
51  
MT9076  
Preliminary Information  
14.0 Error Insertion  
In T1 mode, six types of error conditions can be inserted into the transmit DS1 data stream through control bits,  
which are located on page 1, address 19H - Error Insertion Word. These error events include the bipolar  
violation errors (BPVE), CRC-6 errors (CRCE), Ft errors (FTE), Fs errors (FSE), payload (PERR) and a loss of  
signal condition (LOSE). The LOSE function overrides the B8ZS encoding function.  
In E1 mode, six types of error conditions can be inserted into the transmit PCM 30 data stream through control  
bits, which are located on page 01H, address 19H. These error events include the bipolar violation errors  
(BPVE), CRC-4 errors (CRCE), FAS errors (FASE), NFAS errors (NFSE), payload (PERR) and a loss of signal  
error (LOSE). The LOSE function overrides the HDB3 encoding function.  
15.0 Per Time Slot Control Words  
There are two per time slot control pages (addresses AH and BH) (T1/E1) occupying a total of 24 unique  
addresses in T1 mode or a total of 32 unique addresses in E1 mode. Each address controls a matching  
timeslot on the 24 DS1 channels (T1) or 32 PCM-30 channels (E1) and the equivalent channel data on the  
receive (DSTo) data. For example address 0 of the first per time slot control page contains program control for  
transmit timeslot 0 and DSTo channel 0.  
Per Time Slot Control Word  
Bit 7  
Bit 0  
T1 Mode  
TXMSG PCI  
RTSL  
RTSL  
LTSL  
LTSL  
TTST RRST RPSIG CC  
E1 Mode  
TXMSG ADI  
TTST RRST RPSIG - - -  
15.1  
Clear Channel Capability  
In T1 mode, when bit zero (CC) in the per time slot control word is set no bit robbing for the purpose of  
signaling will occur in this channel. This bit is not used in E1 mode.  
15.2  
Microport signaling  
When bit one (RPSIG) is set, the transmit signaling for the addressed channel can only be programmed by  
writing to the transmit signaling page (pages 5H and 6H) via the microport. If zero, the transmit signaling  
information is constantly updated with the information from the equivalent channel on CSTi.  
15.3  
Per Time Slot Looping  
Any channel or combination of channels may be looped from transmit (sourced from DSTi) to receive (output  
on DSTo) STBUS channels. When bit four (LTSL) in the Per Time Slot Control Word is set the data from the  
equivalent transmit timeslot is looped back onto the equivalent receive channel.  
Any channel or combination of channels may be looped from receive (sourced from the line data) to transmit  
(output onto the line) channels. When bit five (RTSL) in the Per Time Slot Control Word is set the data from the  
equivalent receive timeslot is looped back onto the equivalent transmit channel.  
Remote Timeslot Loopback and Local Timeslot should not be simultaneously activated in the same timeslot.  
52  
Preliminary Information  
MT9076  
15.4  
PRBS Testing  
If the control bit ADSEQ is zero (from master control page 1 - access control word), any channel or combination  
15  
of transmit channels may be programmed to contain a generated pseudo random bit sequence (2 -1). The  
channels are selected by setting bit three (TTST), in the per time slot control word.  
If the control bit ADSEQ is zero, any combination of receive channels may be connected to the PRBS decoder  
15  
(2 -1). Each error in the incoming sequence causes the PRBS error counter to increment. The receive  
channels are selected by setting bit 2 (RRST) in the per time slot control word.  
If PRBS is performed during a metallic or external looparound, per time slot control words with TTST set should  
have RRST set as well.  
15.5  
Digital Milliwatt  
If the control bit ADSEQ is one, a digital milliwatt sequence (Table 18) in T1 mode or (Table 19) in E1 mode  
may be transmit on any combination of selected channels. The channels are selected by setting bit three  
(TTST), in the Per Time Slot Control Word.  
Under the same control condition (ADSEQ equal to one), the same digital milliwatt sequence is available to  
replace received data on any combination of DSTo channels. This is accomplished by setting bit two (RRST) in  
the Per Time Slot Control Word for the corresponding channel.  
Bit 1  
Bit 2  
Bit 3  
Bit 4  
Bit 5  
Bit 6  
Bit 7  
Bit 8  
0
0
0
0
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
1
1
0
0
1
1
1
1
1
1
1
1
1
1
0
0
1
1
0
0
1
1
1
1
1
1
1
1
1
0
1
1
0
0
1
1
0
Table 18 - Digital Milliwatt Pattern (T1)  
Bit 1  
Bit 2  
Bit 3  
Bit 4  
Bit 5  
Bit 6  
Bit 7  
Bit 8  
0
0
0
0
1
1
1
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
1
1
0
1
0
0
0
0
0
0
0
1
0
0
1
1
0
0
0
0
0
0
0
0
0
0
1
1
0
0
1
1
Table 19 - A-Law Digital Milliwatt Pattern (E1)  
15.6  
Per Channel Inversion  
When bit six (PCI) in the Per Time Slot Control Word is set both transmit and receive data for the selected  
channel is inverted before going onto the line / DSTo respectively.  
53  
MT9076  
Preliminary Information  
15.7  
Transmit Message  
When bit seven (TXMSG) in the Per Time Slot Control Word is set the data transmit in the selected channel is  
sourced from the transmit message word in Master Control page 1.  
16.0 Alarms  
The following alarms are detected by the receiver in T1 mode. Each may generate a maskable interrupt:  
D4 Yellow Alarm - in D4 mode there are two possible yellow alarm signals. If control bit D4SECY is set low,  
(page 1H, address 11H, bit 1) the criteria for a yellow alarm is an excess of ’0’s (more than 285) in bit position  
2 of incoming DS0 channels during an integration period of 1.5 milliseconds. It is cleared after more than 3 ’1’s  
are detected in bit position 2 of normal data in a 1.5 millisecond integration period. If D4SECY is set high the  
secondary yellow alarm is selected. The detection criteria becomes 2 consecutive ’1’s in the Sbit position of the  
12th frame.  
ESF Yellow Alarm - In ESF mode, there are two possible yellow alarm signals. If control bit JYEL (page 1H,  
address 14H, bit 0) is set low the criteria for a yellow alarm is a pattern 00000000 11111111 in seven or more  
code words out of ten, If JYEL is set high, the criteria for a yellow alarm is a pattern 11111111 11111111 in  
seven or more code words out of ten.  
All Ones - This bit (page 3H, address 11H, bit 3) is set if less than six zeros are received on the incoming line  
data during a 3 ms interval  
Loss of Signal - a loss of signal condition occurs when the receive signal level is lower than 20dB or 40 dB  
below the nominal signal level for at least a millisecond or when 32 or 192 (control bit L32Z (page 01H, address  
19H, bit 1) consecutive zeros have been received. A loss of signal condition will terminate when an average  
ones density of at least 12.5% has been received over a period of 193 contiguous pulse positions starting with  
a pulse. The loss of signal is reported in the Receive Signal Status Word - (page 3, address 16H bit 4).  
The following alarms are detected by the receiver in E1 mode. Each may generate a maskable interrupt:  
Remote Alarm Indication (RAI) - bit 3 (A) of the receive NFAS;  
Alarm Indication Signal (AIS) - unframed all ones signal for at least a double frame (512 bits) or two double  
frames (1024 bits);  
Channel 16 Alarm Indication Signal - all ones signal in channel 16;  
Auxiliary pattern - 101010... pattern for at least 512 bits;  
Loss of Signal - a loss of signal condition occurs when the receive signal level is lower than 20dB or 40 dB (by  
setting the bit ELOS on page 02H, address 10H, bit 3) below the nominal signal level for more than a  
millisecond or when more than 32 or 192 (control bit L32Z (page 01H, address 19H 9 bit 1) zeros have been  
received in a row. A loss of signal condition will terminate when an average ones density of at least 12.5% has  
been received over a period of 192 contiguous pulse positions starting with a pulse.  
Remote signaling Multiframe Alarm - (Y-bit) of the multiframe alignment signal.  
The alarm reporting latch (address 12H page 04H) contains a register whose bits are set high for selected  
alarms. These bits stay high until the register is read. This allows the controller to record intermittent or  
sporadic alarm occurances.  
16.1  
Automatic Alarms  
In E1 mode, the transmission of RAI and signaling multiframe alarms can be made to function automatically  
from control bits ARAI and AUTY (page 01H, address 10H). When ARAI = 0 and basic frame synchronization is  
lost (SYNC = 1), the MT9076 will automatically transmit the RAI alarm signal to the far end of the link. The  
transmission of this alarm signal will cease when basic frame alignment is acquired.  
When AUTY = 0 and signaling multiframe alignment is not acquired (MFSYNC = 1), the MT9076 will  
automatically transmit the multiframe alarm (Y-bit) signal to the far end of the link. This transmission will cease  
when signaling multiframe alignment is acquired.  
54  
Preliminary Information  
MT9076  
17.0 Detected Events  
17.1  
T1 mode  
17.1.1 Severely Errored Frame Event  
In T1 mode, bit 5 page 3H address 10H toggles whenever a sliding window detects 2 framing errors events (Ft or  
ESF) in a sliding window of 6.  
17.1.2 Loop Code Detect  
T1.403 defines SF mode line loopback activate and deactivate codes. These codes are either a framed or un-  
framed repeating bit sequence of 00001 for activation or 001 for deactivation. The standard goes on to say that  
these codes will persist for five seconds or more before the loopback action is taken. In T1 mode MT9076 will  
detect both framed and unframed line activate and de-activate codes even in the presence of a BER of 3 x 10-  
3. Line Loopback Disable Detect - LLDD - in the Alarm Status Word (bit 0 address 11H of page 3H) will be  
asserted when a repeating 001 pattern (either framed or unframed) has persisted for 48 milliseconds. Line  
Loopback Enable Detect LLED in the Alarm Status Word will be asserted when a repeating 00001 pattern  
(either framed or unframed) has persisted for 48 milliseconds.  
17.1.3 Pulse Density Violation Detect  
In T1 mode, bit 2 of address 11H on page 3H (PDV) toggles if the receive data fails to meet ones density  
requirements. It will toggle upon detection of 16 consecutive zeros on the line data, or if there are less than N  
ones in a window of 8(N+1) bits - where N = 1 to 23.  
17.1.4 Timer Outputs  
In T1 mode, MT9076 has a one second timer derived from the 20 Mhz oscillator pins. The timer may be used to  
trigger interrupts for T1.403/408 performance messaging.  
17.2  
E1 mode  
17.2.1 Consecutive Frame Alignment Patterns (CONFAP)  
Two consecutive frame alignment signals in error.  
17.2.2 Receive Frame Alignment Signals  
These bits are received on the PCM 30 and link in bit positions two to eight of time slot 0 - frame alignment  
signal. These signals form the frame alignment signal and should be 0011011.  
17.2.3 Receive Non Frame Alignment Signal  
This signal is received on the PCM 30 and link in bit position two of time slot 0 - non frame alignment signal.  
17.2.4 Receive Multiframe Alignment Signals  
These signal are received on the PCM 30 and link in bit position one to four of time slot 16 of frame zero of  
every signaling multiframe.  
18.0 Interrupts  
The MT9076 has an extensive suite of maskable interrupts, which are divided into four categories based on the  
type of event that caused the interrupt. Each interrupt has an associated mask and interrupt bit. When an  
unmasked interrupt event occurs, IRQ will go low and one or more bits of the appropriate interrupt register will  
go high(T1/E1). After each interrupt register is read it is automatically cleared. When all interrupt registers are  
cleared IRQ will return to a high impedance state. This function can also be accomplished by toggling the INTA  
bit (page 1, address 1AH.)  
55  
MT9076  
Preliminary Information  
All the interrupts of the MT9076 in T1 and E1 mode are maskable. This is accomplished through interrupt mask  
words zero to three, which are located on page 1, addresses 1BH to 1EH and the (optional) HDLC interrupt  
mask located at address 16 of page B.  
After a MT9076 reset (RESET pin or RST control bit), all interrupts are masked.  
All interrupts may be suspended, without changing the interrupt mask words, by making the SPND control bit of  
page 1, address 1AH high.  
All interrupts are cleared by forcing the pin TxAO low  
18.1  
Interrupts on T1 Mode  
Interrupt Mask Word Zero  
Bit 7  
Bit 0  
TFSYNI MFSYNI TSAI  
AISI  
LOSI  
SEI  
TxSLPI RxSLPI  
Interrupt Mask Word One  
Bit 7  
Bit 0  
FEI  
CRCI YELI COFAI LCVI PRBSI PDVI  
- - -  
Interrupt Mask Word Two  
Bit 7  
Bit 0  
FEO CRCO OOFO COFAO LCVO PRBSO MFOOFO - - -  
Interrupt Mask Word Three  
Bit 7  
Bit 0  
- - -  
- - -  
- - -  
LCDI 1SECI 5SECI BIOMI SIGI  
HDLC Interrupt Masks  
Bit 7  
Bit 0  
Ga  
EOPD TEOP EopR TxFl FATxU RxFf RxOv  
18.2  
Interrupts on E1 Mode  
Interrupt Mask Word Zero  
Bit 7  
Bit 0  
SYNI  
MFSYI CSYNI AISI  
LOSI CEFI  
YI  
SLPI  
Interrupt Mask Word One  
Bit 7  
Bit 0  
FERI  
CRCI  
EBI  
AIS16I LCVI PRBSI AUXPI RAII  
Interrupt Mask Word Two  
Bit 7  
Bit 0  
FEOM CRCO EBOI  
- - -  
LCVO PRBSO PRBSMO  
- - -  
56  
Preliminary Information  
MT9076  
Interrupt Mask Word Three  
Bit 7  
Bit 0  
- - -  
- - -  
- - -  
JAI  
1SECI 5SECI RCRI SIGI  
HDLC Interrupt Masks  
Bit 7  
Bit 0  
Ga  
EOPD TEOP EopR TxFl FATxU RxFf RxOv  
19.0 Digital Framer Mode  
19.1  
T1 Mode  
Setting bit 4 in the Configuration Control Word (address 10H of Master Control Page 2) disables the LIU and  
converts the MT9076 into a digital T1 transceiver. The digital 2.048 Mb/s ST-BUS backplane maps into transmit  
and receive digital 1.544 Mb/s streams. The 1.544 Mb/s transmit streams may be formatted for single phase  
NRZ (by setting bit 7 of the LIU Control Word - Master Page 1 high) or two phase NRZ. The data rate  
conversion (between 2.048 Mb/s and 1.544 Mb/s) is done within the MT9076. The transmit 1.544 MHz clock is  
internally generated from a PLL that locks onto the input C4b clock. This clock is then output on pin E1.5o/  
Exclk (PLCC pin 44 - LQFP pin 22). The digital 1.544 Mb/s transmit data is output on pins TXA and TXB (PLCC  
pins 37,38 - LQFP pins 12, 13) with the rising edge of pin Exclk. If the control bit Tx8KEN is set high (page 2H  
address 10H bit 2) the pin RxMF/TxFP will generate an 8 KHz positive frame pulse synchronous with the Sbit  
clocked out on TXA/TXB. Receive digital data is clocked in on pins RRING and RTIP. This data is clocked in  
with the rising edge of the input 1.544 Mhz clock S/FR/Exclki (PLCC pin 66, LQFP pin 48).  
19.1.1 E1 mode  
Setting bit 4 in the Configuration Control Word (address 10H of Master Control Page 2) disables the LIU and  
converts the MT9076 into a digital E1 transceiver. The digital 2.048 Mb/s ST-BUS backplane maps into transmit  
and receive digital 2.048 Mb/s streams. The 2.048 Mb/s transmit data streams may be formatted for single  
phase NRZ (by setting bit 7 of the LIU Control Word - Master Page 1 high) or two phase NRZ. The transmit  
2.048 MHz clock is derived from the input C4b clock. This clock is then output on pin Exclk (PLCC pin 44 -  
LQFP pin 22). The digital 2.048 Mb/s transmit data is output on pins TXA and TXB (PLCC pins 37,38 - LQFP  
pins 12, 13) with the rising edge of Exclk. If the control bit Tx8KEN is set high (page 2H address 10H bit 2) the  
pin RxMF/TxFP will generate an 8 KHz positive frame pulse synchronous with the Sbit clocked out on TXA/  
TXB. Receive digital data is clocked in on pins RRING and RTIP. This data is clocked in with the rising edge of  
the input 2.048 Mhz clock S/FR/Exclki (PLCC pin 66, LQFP pin 48).  
57  
MT9076  
Preliminary Information  
20.0 Control and Status Registers  
20.1  
T1 Mode  
20.1.1 Master Control 1 (Page 01H) (T1)  
Address  
Register  
Function  
(A4A3A2A1A0)  
10H (Table 21)  
11H (Table 22)  
12H (Table 23)  
Framing Mode Select  
ESF, SCL96, CXC, RS1-0, FSI, ReFR,  
MFReFR  
Transmit Alarm Control Word  
Data Link Control Word  
ESFYEL, TXSECY, D4YEL, TxAO, LUA, LDA,  
D4SECY, SO  
EDL, BIOMEn, EXZ, TxPDVS, TxSYNC, TRSP,  
JTS, H1R64  
13H (Table 24)  
14H (Table 25)  
Transmit Bit Oriented Message  
signaling Control Word  
BIOMTx7-0  
DSToEn, CSToEn, RBEn, DBEn, MSN, SM1-0,  
JYEL  
15H (Table 26)  
Coding and Loopback Control Word  
RxB8ZS, MLBK,TxB8ZS,FBS, DLBK, RLBK,  
SLBK, PLBK  
16H (Table 27)  
17H (Table 28)  
18H (Table 29)  
19H (Table 30)  
Reserved  
Set all bits to zero for normal operation  
Transmit Elastic buffer Set Delay Word  
Transmit Message Word  
Error Insertion Word  
TxTSD7-0  
TXM7-0  
BPVE, CRCE, FTE, FSE, LOSE, PERR, L32Z,  
LOS/LOF  
1AH (Table 31)  
1BH (Table 32)  
1CH (Table 33)  
1DH (Table 34)  
1EH (Table 35)  
1FH (Table 36)  
Reset Control Word  
RST, SPND, INTA, CNTCLR, SAMPLE, OOFP,  
D20  
Interrupt Mask Word Zero  
Interrupt Mask Word One  
Interrupt Mask Word Two  
Interrupt Mask Word Three  
LIU Receiver Word  
TFSYNIM, MFSYNIM, BIOMTIM, AISIM,  
LOSIM, SEFIM, TxSLPIM, RxSLPIM  
FEIM, CRCIM, YELIM, LCVIM, COFAIM,  
PRBSIM, PDVIM  
FEOM, CRCOM, OOFOM, COFAOM, LCVOM,  
PRBSOM, PRBSMFOM,MFOOFOM  
HDLC0IM,HDLC1IM,HDLC2IM,LCDIM,  
1SECIM, 5SECIM, BIOIM, SIGIM  
NRZ, Res, RxA1-0, RxEQ2-0  
Table 20 - Master Control 1 (Page 1) (T1)  
58  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
ESF  
Extended Super Frame. Setting this bit enables transmission and reception of the 24 frame  
superframe DS1 protocol.  
6
5
SLC96 SLC96 Mode Select. Setting this bit enables input and output of the Fs bit pattern on the TxDL  
and RxDL pins. Frame synchronization is the same as in the case of D4 operation. The  
transmitter will insert A and B bits every 6 frames after synchronizing to the Fs pattern clocked  
into Txdl. Receive Fs bits are not monitored for the Framing Bit Error Counter.  
CXC  
Cross Check. Setting this bit in ESF mode enables a cross check of the CRC-6 remainder  
before the frame synchronizer pulls into sync. This process adds at least 6 milliseconds to the  
frame synchronization time. Setting this bit in D4 (not ESF) mode enables a check of the Fs  
bits in addition to the Ft bits during frame synchronization  
4 - 3 RS1- 0 Reframe Select 1 - 0. These bits set the criteria for an automatic reframe in the event of  
framing bits errors. The combinations available are:  
RS1 - 0, RS0 - 0 = sliding window of 2 errors out of 4.  
RS1 - 0, RS0 - 1 = sliding window of 2 errors out of 5.  
RS1 - 1, RS0 - 0 = sliding window of 2 errors out of 6.  
RS1 - 1, RS0 - 1 = no reframes due to framing bit errors.  
2
FSI  
Fs Bit Include. Only applicable in D4 mode (not ESF or SLC96). Setting this bit causes  
errored Fs bits to be included as framing bit errors. A bad Fs bit will increment the Framing  
Error Bit Counter, and will potentially cause a reframe (if it is the second bad framing bit out of  
5). The Fs bit of the receive frame 12 will only be included if D4SECY is set.  
1
0
ReFR  
Reframe. A low - to - high transition on this bit causes an automatic reframe.  
MFReFR MultiFrame Reframe. Only applicable in D4 or SLC96 mode. A low - to - high transition on this  
bit causes an automatic multiframe reframe. The signaling bits are frozen until multiframe  
synchronization is achieved. Terminal frame synchronization is not affected.  
Table 21 - Framing Mode Select (T1)  
(Page 1, Address 10H)  
59  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
ESFYEL ESF Yellow Alarm. Setting this bit while in ESF mode causes a repeating pattern of eight 1’s  
followed by eight 0’s to be insert onto the transmit FDL (Japan Telecom bit set low - see Data  
Link Control Word) or sixteen 1’s (Japan Telecom bit set high).  
6
TXSECY Transmit Secondary D4 Yellow Alarm. Setting this bit (in D4 mode) causes the S bit of  
transmit frame 12 to be set.  
5
4
D4YEL D4 Yellow Alarm. When set bit 2 of all DS0 channels are forced low.  
TxAO  
Transmit All Ones. When low, this control bit forces a framed or unframed (depending on the  
state of Transmit Alarm Control bit 0) all ones to be transmit at TTIP and TRING.  
3
2
1
LUA  
Loop Up Activate. Setting this bit forces transmission of a framed or unframed (depending on  
the state of Transmit Alarm Control bit 0) repeating pattern of 00001.  
LDA  
Loop Down Activate. Setting this bit forces transmission of a framed or unframed (depending  
on the state of Transmit Alarm Control bit 0) repeating pattern of 001.  
D4SECY D4 Secondary Alarm. Set this bit for trunks employing the secondary Yellow Alarm. The Fs bit  
in the 12th frame will not be used for counting errored framing bits. If a one is received in the Fs  
bit position of the 12th frame a Secondary Yellow Alarm Detect bit will be set.  
0
SO  
Overhead bits Override. If set, this bit forces the overhead bits to be inserted as an overlay on  
any of the following alarm conditions: i) transmit all ones, ii) loop up code insertion, iii) loop  
down code insertion.  
Table 22 - Transmit Alarm Control Word (T1)  
(Page 1, Address 11H)  
60  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
EDL  
Enable Data Link. Setting this bit multiplexes the serial stream clocked in on pin TxDL into  
the FDL bit position (ESF mode) or the Fs position (D4 mode).  
6
BIOMEn Bit Oriented Messaging Enable. Setting this bit enables transmission of bit - oriented  
messages on the ESF facility data link. The actual message transmit at any one time is  
contained in the BIOMTx register (page 1, address 13H). The receive bit - oriented message  
register is always active, although the interrupt associated with it may be masked.  
5
4
EXZ  
Excess Zeros. Setting this bit causes each occurance of received excess zeros to increment  
the Line Code Violation Counter. Excess zeros are defined as 8 or more successive zeros for  
B8ZS encoded data, or 16 or more successive zeros for non-B8ZS encoded data.  
TxPDVS Transmit Pulse Density Violation Screen. Setting this bit causes ones to be injected into  
the transmit data in the event that a violation of the ones density requirement is detected in  
the outgoing data.  
3
2
TxSYNC Transmit Synchronization. Setting this bit causes the transmit multiframe boundary to be  
internally synchronized to the incoming Sbits on DSTi channel 31 bit 0.  
TRSP  
Transparent Mode. Setting this bit causes unframed data to be transmit from DSTi channels  
0 to 23 and channel 31 bit 7 to be transmit transparently onto the DS1 line. Unframed data  
received from the DS1 line is piped out on DSTo channels 0 to 23 and channel 31 bit 0.  
1
0
JTS  
Japan Telecom Synchronization. Setting this bit forces the inclusion of Sbits in the CRC-6  
calculation.  
H1R64  
HDLC Rate Select. Setting this pin high while an HDLC is activated on a timeslot enables 64  
Kb/s operation. Setting this pin low while an HDLC is activated enables 56 Kb/s operation (this  
prevents data corruption due to forced bit stuffing).  
Table 23 - Data Link Control Word (T1)  
(Page 1, Address 12H)  
Bit  
Name  
Functional Description  
7 - 0 BIOMTx7-0 Transmit Bit Oriented Message. The contents of this register are concatenated with a  
sequence of eight 1’s and continuously transmit in the FDL bit position of ESF trunks.  
Normally the leading bit (bit 7) and last bit (bit 0) of this register are set to zero.  
Table 24 - Transmit Bit Oriented Message (T1)  
(Page 1, Address 13H)  
61  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
6
5
DSToEn DSTo Enable. If zero pin DSTo is tristate. If set the pin DSTo is enabled.  
CSToEn CSTo Enable. If zero pin CSTo is tristate. If set the pin CSTo is enabled.  
RBEn  
DBEn  
MSN  
Robbed Bit signaling Enable. Setting this bit multiplexes the AB or ABCD signaling bits into  
bit position 8 of all DS0 channels every 6th frame.  
4
3
Debounce Enable. Setting this bit causes incoming signaling bits to be debounced for a  
period of 6 to 9 milliseconds before reporting on CSTo or in the Receive signaling Bits Page.  
Most Significant Nibble. If set to one the most significant nibble of CSTi and CSTo are  
activated. The reporting stream CSTo contains the signaling information for the equivalent  
channel in the most significant nibble, and least significant nibble is tristate. If set to zero the  
least significant nibble is active for CSTi and CSTo and the most significant nibble of CSTo is  
tristate.  
2-1  
SM1-0  
JYEL  
signaling Message. These two bits are used to fill the vacant bit positions available on CSTo  
when the 3VJET is operating on a D4 trunk. The first two bits of each reporting nibble of  
CSTo contain the AB signaling bits. The last two will contain SM1 and SM0 (in that order).  
When the 3VJET is connected to ESF trunks four signaling bits (ABCD) are reported and the  
bits SM1-0 become unused.  
0
Japan Yellow Alarm Set this bit high to selects a pattern of 16 ones (111111111111111) as  
the ESF yellow alarm, both for the case when an ESF yellow alarm is to be transmit, or in  
recognizing a received yellow alarm.  
Table 25 - signaling Control Word (T1)  
(Page 1, Address 14H)  
Bit  
Name  
Functional Description  
7
6
RxB8ZS Receive B8ZS Enable. If one, receive B8ZS decoding is enabled.  
MLBK  
Metallic Loopback. If one, then RRTIP/RRING are connected directly to TTIP and TRING  
respectively. If zero, then this feature is disabled.  
5
4
TxB8ZS Transmit B8ZS Enable. If one, all zero octets are substituted with B8ZS codes.  
FBS  
Forced Bit Stuffing. If set any transmit DS0 channel containing all zeros has bit 7 forced  
high.  
3
DLBK  
Digital Loopback. If one, then the digital stream to the transmit LIU is looped back in place  
of the digital output of the receive LIU. Data coming out of DSTo will be a delayed version of  
DSTi. If zero, this feature is disabled.  
2
1
0
RLBK  
SLBK  
PLBK  
Remote Loopback. If one, then all time slots received on RRTIP/RRING are connected to  
TTIP/TRING on the DS1 side of the 3VJET. If zero, then this feature is disabled.  
ST-BUS Loopback. If one, then all time slots of DSTi are connected to DSTo on the ST-BUS  
side of the 3VJET. If zero, then this feature is disabled. See Loopbacks section.  
Payload Loopback. If one, then all time slots received on RTIP/RRING are connected to  
TTIP/TRING on the ST-BUS side of the 3VJET. If zero, then this feature is disabled.  
Table 26 - Coding and Loopback Control Word (T1)  
(Page 1, Address 15H)  
62  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7-0  
TxSD7-0 Transmit Set Delay Bits 7-0. Writing to this register forces a one time setting of the delay  
through the transmit slip buffer. The delay is defined as the time interval between the write of  
the transmit STBUS channel containing DS1 timeslot 1 and its subsequent read. The delay  
is modified by moving the position of the internally generated DS1 frame boundary. The  
delay (when set) will always be less than 1 frame (125uS). This register must be  
programmed with a non - zero value.  
Table 27 - Transmit Elastic Buffer Set Delay Word (T1)  
(Page 1, Address 17H)  
Bit  
Name  
Functional Description  
7-0  
TxM7-0 Transmit Message Bits 7 - 0. The contents of this register are transmit into those outgoing  
DS1 channels selected by the Per Time Slot Control registers.  
Table 28 - Transmit Message Word (T1)  
(Page 1, Address 18H)  
Bit  
Name  
Functional Description  
7
BPVE  
Bipolar Violation Error Insertion. A zero-to-one transition of this bit inserts a single bipolar  
violation error into the transmit DS1 data. A one, zero or one-to-zero transition has no  
function.  
6
5
CRCE  
FTE  
CRC-6 Error Insertion. A zero-to-one transition of this bit inserts a single CRC-6 error into  
the transmit ESF DS1 data. A one, zero or one-to-zero transition has no function.  
Terminal Framing Bit Error Insertion. A zero-to-one transition of this bit inserts a single  
error into the transmit D4 Ft pattern or the transmit ESF framing bit pattern (in ESF mode).  
A one, zero or one-to-zero transition has no function.  
4
FSE  
Signal Framing Bit Error Insertion. A zero-to-one transition of this bit inserts a single error  
into the transmit Fs bits (in D4 mode only). A one, zero or one-to-zero transition has no  
function.  
3
2
1
0
LOSE  
PERR  
L32Z  
Loss of Signal Error Insertion. If one, the 3VJET transmits an all zeros signal (no pulses).  
Zero code suppression is overridden. If zero, data is transmitted normally.  
Payload Error Insertion. A zero - to - one transition of this bit inserts a single bit error in the  
transmit payload. A one, zero or one-to-zero transition has no function.  
Digital Loss of Signal Selection. If one, the threshold for digital loss of signal is 32  
successive zeros. If zero, the threshold is set to 192 successive zeros.  
LOS/LOF Loss of Signal or Loss of Frame Selection. If one, pin LOS will go high when a loss of  
signal state exits (criteria as per LLOS status bit). If low, pin LOS will go high when either a  
loss of signal or a loss of frame alignment state exits.  
Table 29 - Error Insertion Word (T1)  
(Page 1, Address 19H)  
63  
MT9076  
Preliminary Information  
Bit Name  
Functional Description  
7
RST  
Software reset. Setting this bit is equivalent to performing a hardware reset. All counters are  
cleared and the control registers are set to their default values. This control bit is internally  
cleared after the reset operation is complete.  
6
5
SPND Suspend Interrupts. If one, the IRQ output will be in a high-impedance state and all interrupts  
will be ignored. If zero, the IRQ output will function normally.  
INTA  
Interrupt Acknowledge. Setting this pin clears all interrupts and forces the IRQ pin into high  
impedance. The control bit itself is then internally cleared.  
4
3
CNTCLR Counter Clear. If one, all status error counters are cleared and held low.  
SAMPLE One Second Sample. Setting this bit causes the error counters (change of frame alignment, loss  
of frame alignment, lcv errors, crc errors, severely errored frame events and multiframes out of  
sync) to be updated on one second intervals coincident with the one second timer (status page 3  
address 12H bit 7).  
2
OOFP Out of Frame Pause. If set high, this bit will suspend operation of the Line Code VIolation  
Counter during an out - of - frame condition; upon achieving terminal frame synchronization the  
counter will resume normal operation. If set low, the Line Code Violation counter will continue to  
count errors even if terminal frame synchronization is lost.  
1
0
--  
Reserved. Set to zero for normal operation.  
D20  
Double20. Set to zero for normal operation. Set high to double clock speed in the HDLC,  
speeding up microport accesses from 160ns between consecutive reads/writes to 80ns between  
consecutive reads/writes.  
Table 30 - Reset Control Word (T1)  
(Page 1, Address 1AH)  
64  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
TFSYNIM Terminal Frame Synchronization Interrupt Mask. When unmasked an interrupt is initiated  
whenever a change of state of loss of terminal frame synchronization condition exists. If 1 -  
unmasked, 0 - masked.  
6
5
MFSYNIM Multiframe Synchronization Interrupt Mask. When unmasked an interrupt is initiated  
whenever a change of state of loss of multiframe synchronization condition exist. If 1 -  
unmasked, 0 - masked  
BIOMTIM Bit Oriented Message Transition Interrupt Mask. When unmasked an interrupt is initiated  
whenever a new BIOM arrives or if the current BIOM stops transmission. If 1 - unmasked, 0 -  
masked.  
4
3
2
1
0
AISIM  
Alarm Indication Signal Interrupt Mask. When unmasked a change of state of received all  
ones condition will initiate an interrupt. If 1 - unmasked, 0 - masked.  
LOSIM Loss of Signal Interrupt Mask. When unmasked an interrupt is initiated whenever a change of  
state of a loss of signal condition exists. If 1 - unmasked, 0 - masked.  
SEFIM  
Severely Errored Frame Interrupt Mask. When unmasked an interrupt is initiated when a  
sequence of 2 framing errors out of 6 occurs. If 1 - unmasked, 0 - masked.  
TxSLPIM Transmit SLIP Interrupt Mask. When unmasked an interrupt is initiated whenever a controlled  
frame slip occurs in the transmit elastic buffer. If 1 - unmasked, 0 - masked.  
RxSLPIM Receive SLIP Interrupt Mask. When unmasked an interrupt is initiated whenever a controlled  
frame slip occurs in the receive elastic buffer. If 1 - unmasked, 0 - masked.  
Table 31 - Interrupt Mask Word Zero (T1)  
(Page 1, Address 1BH)  
Bit Name  
Functional Description  
7
FEIM Framing Bit Error Interrupt Mask. When unmasked an interrupt is initiated whenever an  
erroneous framing bit is detected (provided the circuit is in terminal frame sync). If 1 - unmasked,  
0 - masked.  
6
5
4
3
CRCIM CRC-6 Error Interrupt Mask. When unmasked an interrupt is initiated whenever a local CRC-6  
error occurs. If 1 - unmasked, 0 - masked.  
YELIM Yellow Alarm Interrupt Mask. When unmasked detection of a yellow alarm triggers an interrupt.  
If 1 - unmasked, 0 - masked.  
COFAIM Change of Frame Alignment Interrupt Mask. When unmasked an interrupt is initiated whenever  
a change of frame alignment occurs after a reframe. If 1 - unmasked, 0 - masked.  
LCVIM Line Code Violation Interrupt Mask. When unmasked an interrupt is initiated whenever a line  
code violation (excluding B8ZS bipolar violations encoding) is encountered. If 1- unmasked, 0 -  
masked.  
2
PRBSIM Pseudo Random Bit Sequence Error Interrupt Mask. When unmasked an interrupt will be  
generated upon detection of an error with a channel selected for PRBS testing. If 1 - unmasked, 0  
- masked.  
1
0
PDVIM Pulse Density Violation Interrupt Mask. When unmasked an interrupt is triggered whenever a  
sequence excess consecutive zeros is received on the line. If 1 - unmasked, 0 - masked.  
- - -  
Unused.  
Table 32 - Interrupt Mask Word One (T1)  
(Page 1, Address 1CH)  
65  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
FEOM  
Framing Bit Error Counter Overflow Interrupt Mask. When unmasked an interrupt is  
initiated whenever the framing bit error counter changes from FFH to 00H. If 1 - unmasked,  
0 - masked.  
6
5
CRCOM  
OOFOM  
CRC-6 Error Counter Overflow Interrupt Mask. When unmasked an interrupt is initiated  
whenever the CRC-6 error counter changes from FFH to 00H. If 1 - unmasked, 0 - masked.  
Out Of Frame Counter Overflow Interrupt Mask. When unmasked an interrupt is initiated  
whenever the out of frame counter changes state from changes from FFH to 00H. If 1 -  
unmasked, 0 - masked.  
4
3
2
1
0
COFAOM Change of Frame Alignment Counter Overflow Interrupt Mask. When unmasked an  
interrupt is initiated whenever the change of frame alignment counter changes from FFH to  
00H. If 1 - unmasked, 0 - masked.  
LCVOM  
Line Code Violation Counter Overflow Interrupt Mask. When unmasked an interrupt is  
initiated whenever the line code violation counter changes from FFH to 00H. If 1-  
unmasked, 0 - masked.  
PRBSOM Psuedo Random Bit Sequence Error Counter Overflow Interrupt Mask. When  
unmasked an interrupt will be generated whenever the PRBS error counter changes from  
FFH to 00H. If 1 - unmasked, 0 - masked.  
PRBSMFOM Psuedo Random Bit Sequence Multiframe Counter Overflow Interrupt Mask. When  
unmasked an interrupt will be generated whenever the multiframe counter attached to the  
PRBS error counter overflows. FFH to 00H. If 1 - unmasked, 0 - masked.  
MFOOFOM Multiframes Out Of Sync Overflow Interrupt Mask. When unmasked an interrupt will be  
generated when the multiframes out of frame counter changes from FFH to 00H. If 1 -  
unmasked, 0 - masked.  
Table 33 - Interrupt Mask Word Two (T1)  
(Page 1, Address 1DH)  
66  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
HDLC0IM HDLC0 Interrupt Mask. When unmasked an interrupt is triggered by an unmasked event in  
HDLC0. If 1 - unmasked, 0 - masked.  
6
5
4
HDLC1IM HDLC1 Interrupt Mask. When unmasked an interrupt is triggered by an unmasked event in  
HDLC1. If 1 - unmasked, 0 - masked.  
HDLC2IM HDLC2 Interrupt Mask. When unmasked an interrupt is triggered by an unmasked event in  
HDLC2. If 1 - unmasked, 0 - masked.  
LCDIM  
Loop Code Detected Interrupt Mask. When unmasked an interrupt is triggered when  
either the loop up (00001) or loop down (001) code has been detected on the line for a  
period of 48 milliseconds. If 1 - unmasked, 0 - masked.  
3
1SECIM One Second Status Interrupt Mask. When unmasked an interrupt is initiated when the  
1SEC status bit (page 3 address 12H bit 7) goes from low to high. If 1 - unmasked, 0 -  
masked.  
2
1
5SECIM Five Second Status Interrupt Mask. When unmasked an interrupt is initiated when the 5  
SEC status bit goes from low to high. If 1 - unmasked, 0 - masked.  
BIOMIM Bit Oriented Message Interrupt Mask. When unmasked an interrupt is initiated when a  
pattern 111111110xxxxxx0 has been received on the FDL that is different from the last  
message. The new message must persist for 8 out the last 10 message positions to be  
accepted as a valid new message. If 1- unmasked, 0 - masked.  
0
SIGIM  
signaling Interrupt Mask. When unmasked an interrupt will be initiated when a change of  
state (optionally debounced - see DBEn in the Data Link, signaling Control Word page 1  
address 12H) is detected in the signaling bits (AB or ABCD) pattern. If 1 - unmasked, 0 -  
masked.  
Table 34 - Interrupt Mask Word Three (T1)  
(Page 1, Address 1EH)  
67  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
NRZ  
NRZ Format Selection. Only used in the digital framer only mode (LIU is disabled). A one  
sets the MT9076 to accept a unipolar NRZ format input stream on RxA as the line input,  
and to transmit a unipolar NRZ format stream on TxB. A zero causes the MT9076 to accept  
a complementary pair of dual rail inputs on RxA/RxB and to transmit a complementary pair  
of dual rail outputs on TxA/TxB.  
6
5
- - -  
Reserved. Set this low for normal operation.  
Res  
Resistor. Set this bit high to connect a 104 ohm internal resistor between RTIP and  
RRING. This is activated where an external 20.8 ohm terminating resistor is in use on a T1  
line.  
4 - 3  
2 - 0  
RxA1-0  
Automatic Receive Equalizer Control. If both bits are set high, the receive equalizer is  
turned on and will compensate for loop length automatically. The control bits RxEQ2-0 will  
be ignored. If both are set low (00) then equalization will be actived using the control bits  
RxEQ2-0.  
RxEQ2-0 Receive Equalization Select. Setting these pins forces a level of equalization of the  
incoming line data.  
RES2 RES1 RES0 Receive Equalization  
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
none  
8 dB  
16 dB  
24 dB  
32dB  
40 dB  
48 dB  
reserved  
These settings have no effect if either of RxA1 and RxA0 are set to one.  
Table 35 - LIU Receiver Word (T1)  
(Page 1, Address 1FH)  
68  
Preliminary Information  
MT9076  
20.1.2 Master Control 2 (Page 02H) (T1)  
Register  
Names  
Address  
(A4A3A2A1A0)  
10H (Table 37)  
11H (Table 38)  
12H  
Configuration Control Word  
LIU Tx Word  
T1/E1, TxEN, LIUEn, ELOS, Tx8KEN, ADSEQ  
CPL, TxLB2-0  
Reserved  
Set all bits to zero for normal operation.  
13H (Table 39) Jitter Attenuator Control Word  
JFC, JFD2-JFD0, JACL  
14H  
Reserved  
Set all bits to zero for normal operation.  
15H  
Reserved  
Set all bits to zero for normal operation.  
16H (Table 40)  
17H (Table 41)  
18H (Table 42)  
19H (Table 43)  
1AH (Table 44)  
1BH (Table 45)  
1CH (Table 46)  
1DH (Table 47)  
1EH (Table 48)  
1FH (Table 49)  
Equalizer High Threshold  
Equalizer Low Threshold  
Serial Config. Word  
HDLC0 Select  
EHT7-0  
ELT7-0  
IMA, T1DM, G.802, 8Men, 8MTS1-0  
En, FDLSEL, CH4-0  
En, CH4-0  
En, CH4-0  
CP6-0  
HDLC1 Select  
HDLC2 Select  
Custom Pulse Word 1  
Custom Pulse Word 2  
Custom Pulse Word 3  
Custom Pulse Word 4  
CP6-0  
CP6-0  
CP6-0  
Table 36 - Master Control 2 (Page 02H) (T1)  
69  
MT9076  
Preliminary Information  
Bit Name  
Functional Description  
7
T1/E1 T1/E1 mode selection. when this bit is zero, the device is in T1 mode. When set high, the device  
is in E1 mode.  
6
5
--  
Reserved. Must be kept at 0 for normal operation.  
TxEN Transmit Enable. Setting this bit low turns off the TTIP and TRING output line drivers. Setting this  
bit high enables them.  
4
LIUEn LIU Enable. Setting this bit low enables the internal LIU front-end. Setting this pin high disables  
the LIU. Digital inputs RXA and RXB are sampled by the rising edge of E1.5i (Exclk) to strobe in  
the received line data. Digital transmit data is clocked out of pins TXA and TXB with the rising edge  
of Exclk  
3
2
ELOS ELOS Enable. Set this bit low to set the analog loss of signal threshold to 40 dB below nominal.  
Set this bit high to set the analog loss of signal threshold to 20 dB below nominal.  
Tx8KEN Transmit 8 KHz Enable. If one, the pin RxMF/TxFP transmits a positive 8 KHz frame pulse  
synchronous with the serial data stream transmit on TXA/TXB. If zero, the pin RxMF/TxFP  
transmits a negative frame pulse synchronous with the multiframe boundary of data coming out of  
DSTo.  
1
0
ADSEQ Digital Milliwatt or Digital Test Sequence. If one, the Alaw digital milliwatt analog test sequence  
will be selected for those channels with per time slot control bits TTST, RRST set. If zero, a PRBS  
generator / detector will be connected to channels with TTST, RRST respectively.  
--  
Reserved. Must be kept at 0 for normal operation.  
Table 37 - Configuration Control Word  
(Page 2, Address 10H) (T1)  
Bit  
Name  
Functional Description  
7-5  
4
--  
--  
Reserved. Must be kept at 0 for normal operation.  
Reserved. Set low for normal operation.  
3
CPL  
Custom Pulse Level. Setting this bit low enables the internal ROM values in generating the  
transmit pulses. The ROM is coded for different line terminations or build out, as specified in the  
LIU Control word. Setting this pin high disables the pre-programmed pulse templates. Each of  
the 4 phases that generate a mark derive their D/A coefficients from the values programmed in  
the CPW registers.  
2-0 TXLB2-0 Transmit Line Build Out 2 - 0. Setting these bits shapes the transmit pulse as detailed in the  
table below:  
TX22  
TXL1  
TXL0  
Line Build Out  
0 to 133 feet/ 0 dB  
133 to 266 feet  
266 to 399 feet  
399 to 533 feet  
533 to 655 feet  
-7.5 dB  
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
-15 dB  
-22.5 dB  
After reset these bits are zero.  
Table 38 - LIU Tx Word  
(Page 2, Address 11H) (T1)  
70  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
6
- - -  
Unused.  
JFC  
Jitter Attenuator FIFO Centre. When this bit is toggled the read pointer on the jitter  
attenuator shall be centered. During this centering the jitter on the JA outputs is increased  
by 0.0625 U.I. This feature is only available when IMA Mode is activated.  
5 - 3 JFD2-JFD0 Jitter Attenuator FIFO Depth Control Bits. These bits determine the depths of the jitter  
attenuator FIFO as shown below:  
JFD2  
JFD1  
JFD0  
Depth  
16  
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
32  
48  
64  
80  
96  
112  
128  
This feature is only available when IMA Mode is activated.  
2
JACL  
- - -  
Jitter Attenuator FIFO Clear Bit. If one, the Jitter Attenuator, its FIFO and status are reset.  
The status registers will identify the FIFO as being empty. However, the actual bit values of  
the data in the JA FIFO will not be reset.  
This feature is only available when IMA Mode is activated.  
1 - 0  
Unused.  
Table 39 - Jitter Attenuation Control Word  
(Page 2, Address 13H) (T1)  
Bit  
Name  
Functional Description  
7-0  
EHT7-0  
Equalizer High Threshold. These bits set the highest possible binary count tolerable  
coming out of the equalized signal peak detector before a lower level of equalization is  
selected. This register is only used when A/D based automatic equalization is selected  
using the Rx LIU Control Word. Recommended value to program is 10111011.  
Table 40 - Equalizer High Threshold  
(Page 2, Address 16H) (T1)  
Bit  
Name  
Functional Description  
7-0  
ELT7-0  
Equalizer Low Threshold. These bits set the lowest possible binary count tolerable coming  
out of the equalized signal peak detector before a higher level of equalization is selected.  
This register is only used when A/D based automatic equalization is selected using the Rx  
LIU Control Word. Recommended value to program is 00110000.  
Table 41 - Equalizer Low Threshold  
(Page 2, Address 17H) (T1)  
71  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
Reserved. Must be kept at 0 for normal operation.  
7-6  
5
--  
IMA  
Inverse Mux Mode. Setting this bit high the I/O ports to allow for easy connection to the  
Mitel MT90220. DSTi becomes a serial 1.544 data stream. C4b becomes a 1.544 MHz clock  
that clocks DSTi in on the falling edge. RXFP becomes a positive framing pulse that is high  
for the first bit (the framing bit) of the serial T1 stream coming from the pin DSto. This stream  
is clocked out on the rising edge of Exclk. Set this pin low for all other applications.  
4
3
--  
Reserved. Must be set to 0 for normal operation.  
G.802  
G.802. Must be kept at 0 for normal operation. Set high for ST-BUS to DSI channel mapping  
as per G.802.  
2
8Men  
8Mb/s Bit Rate Select. Setting this bit low enables a serial bit rate on DSTi, CSTi and DSTo,  
CSTo of 2.048 Mb/s. Setting this bit high enables a gapped serial bit rate of 8.192 Mb/s on  
DSTi, CSTi, DSTo and CSTo.  
1-0  
8MTS1-0 8 Mb/s Time Slot Select. These two bits select the active timeslots on the serial 8.192 Mb/  
s channels. During the active timeslots incoming serial data on DSTi and CSTi is clocked  
into the device, and data is clocked out onto DSTo and CSTo. During inactive timeslots DSTo  
and CSTo are tristate. For all selections every fourth 8 Mb/s timeslot is active for the first 96  
timeslots (24 x 8).  
The timeslot selection (T1 mode) is as follows:  
8MTS1 8MST0  
Active timeslots  
0 0  
0 1  
1 0  
0,4,8,12,16,20,24,28,32,36,40,44,48,52,56,60,64,68,72,76,80,84,88,92  
1,5,9,13,17,21,25,29,33,37,41,45,49,53,57,61,65,69,73,77,81,85,89,93  
2,6,10,14,18,22,26,30,34,38,42,46,50,54,58,62,66,70,74,78,82,86,90,94  
1 1 3,7,11,15,19,23,27,31,35,39,43,47,51,55,59,63,67,71,75,79,83,87,91,95  
Table 42 - Serial Config. Word  
(Page 2, Address 18H) (T1)  
Bit  
Name  
Functional Description  
7
En  
Enable. Set high to attach the HDLC0 controller to the channel specified below. Set low to  
disconnect the HDLC0.  
6
FDLSEL  
Facility Data Link Select. Set this bit to 0 to attach HDLC0 to the 4 kb/s facility data link.  
Set this bit to 1 to attach HDLC0 to a payload timeslot.  
5
--  
Reserved. Must be kept at 0 for normal operation.  
4-0  
CH4-0  
Channel 4-0. This 5 bit number specifies the channel time HDLC0 will be attached to if  
enabled. Channel 0 is the first channel in the frame. Channel 23 is the last channel available  
in a T1 frame. If enabled in a channel, HDLC data will be substituted for data from DSTi on  
the transmit side. Receive data is extracted from the incoming line data before the elastic  
buffer.  
Table 43 - HDLC0 Select  
(Page 2, Address 19H) (T1)  
72  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
En  
Enable. Set high to attach the HDLC1 controller to the channel specified below. Set low to  
disconnect the HDLC1.  
6-5  
4-0  
--  
Reserved. Must be kept at 0 for normal operation.  
CH4-0  
Channel 4-0. This 5 bit number specifies the channel time HDLC1 will be attached to if  
enabled. Channel 0 is the first channel in the frame. Channel 23 is the last channel available  
in a T1 frame. If enabled in a channel, HDLC data will be substituted for data from DSTi on  
the transmit side. Receive data is extracted from the incoming line data before the elastic  
buffer.  
Table 44 - HDLC1 Select  
(Page 2, Address 1AH) (T1)  
Bit  
Name  
Functional Description  
7
En  
Enable. Set high to attach the HDLC2 controller to the channel specified below. Set low to  
disconnect the HDLC2.  
6-5  
4-0  
- -  
Reserved. Must be kept at 0 for normal operation.  
CH4-0  
Channel 4-0. This 5 bit number specifies the channel time HDLC2 will be attached to if  
enabled. Channel 0 is the first channel in the frame. Channel 23 is the last channel available  
in a T1 frame. If enabled in a channel, HDLC data will be substituted for data from DSTi on  
the transmit side. Receive data is extracted from the incoming line data before the elastic  
buffer.  
Table 45 - HDLC2 Select  
(Page 2, Address 1BH) (T1)  
Bit  
Name  
Functional Description  
7
- -  
Reserved. Must be kept at 0 for normal operation.  
6-0  
CP6-0  
Custom Pulse. These bits provide the capability for programming the magnitude setting for  
the TTIP/TRING line driver A/D converter during the first phase of a mark. The greater the  
binary number loaded into the register, the greater the amplitude driven out. This feature is  
enabled when the control bit 3 - CPL of the Custom Tx Pulse Enable Register - address 11H  
of Page 2 is set high.  
Table 46 - Custom Pulse Word 1  
(Page 2, Address 1CH) (T1)  
Bit  
Name  
Functional Description  
7
-
Reserved. Must be kept at 0 for normal operation.  
6-0  
CP6-0  
Custom Pulse. These bits provide the capability for programming the magnitude setting for  
the TTIP/TRING line driver A/D converter during the second phase of a mark. The greater  
the binary number loaded into the register, the greater the amplitude driven out. This  
feature is enabled when the control bit 3 - CPL of the Custom Tx Pulse Enable Register -  
address 11H of Page 2 is set high.  
Table 47 - Custom Pulse Word 2  
(Page 2, Address 1DH) (T1)  
73  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
Reserved. Must be kept at 0 for normal operation.  
7
- -  
6-0  
CP6-0  
Custom Pulse. These bits provide the capability for programming the magnitude setting for  
the TTIP/TRING line driver A/D converter during the third phase of a mark. The greater the  
binary number loaded into the register, the greater the amplitude driven out. This feature is  
enabled when the control bit 3 - CPL of the Custom Tx Pulse Enable Register - address 11H  
of Page 2 is set high.  
Table 48 - Custom Pulse Word 3  
(Page 2, Address 1EH) (T1)  
Bit  
Name  
Functional Description  
7
- -  
Reserved. Must be kept at 0 for normal operation.  
6-0  
CP6-0  
Custom Pulse. These bits provide the capability for programming the magnitude setting for  
the TTIP/TRING line driver A/D converter during the fourth phase of a mark. The greater the  
binary number loaded into the register, the greater the amplitude driven out. This feature is  
enabled when the control bit 3 - CPL of the Custom Tx Pulse Enable Register - address 11H  
of Page 2 is set high.  
Table 49 - Custom Pulse Word 4  
(Page 2, Address 1FH) (T1)  
74  
Preliminary Information  
MT9076  
20.1.3 Master Status 1 (Page03H) (T1)  
Address  
(A4A3A2A1A0)  
Register  
Function  
10H (Table 52)  
11H (Table 53)  
Synchronization Status Word  
Alarm Status Word  
TFSYNC, MFSYNC, SE, LOS  
D4YALM, D4Y48, SECYEL, ESFYEL, BLUE,  
PDV, LLED, LLDD  
12H (Table 54)  
13H (Table 55)  
14H (Table 56)  
15H (Table 57)  
16H (Table 58)  
17H (Table 59)  
18H (Table 60)  
19H  
Timer Status Word  
Most Significant Phase Status Word  
Least Significant Phase Status Word  
Receive Bit Oriented Message  
Receive Signal Status Word  
MSB Transmit Slip Buffer  
Transmit Slip Buffer Delay  
- - -  
1SEC, 2SEC, 5SEC  
RSLIP, RSLPD, RxFRM, RxFT, RxSBD2-0  
RxTS4-0, RxBC2-0  
RxBOM7-0  
LLOS  
TSLIP, TSLPD, TxSBMSB  
TxTS4-0, TxBC2-0  
Unused.  
1AH  
- - -  
Unused.  
1BH  
- - -  
Unused.  
1CH  
- - -  
Reserved.  
1DH (Table 61)  
1EH (Table 62)  
1FH (Table 63)  
Analog Peak Detect  
Equalized Signal Peak Detect  
Identification Register  
AP7-0  
ESP7-0  
Internally set to 01111000  
Table 50 - Master Status 1 (Page 3) (T1)  
75  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
TFSYNC Terminal Frame Synchronization. Indicates the Terminal Frame Synchronization status (1  
- loss; 0 - acquired). For ESF links terminal frame synchronization and multiframe  
synchronization are synonymous.  
6
5
MFSYNC Multiframe Synchronization. Indicates the Multiframe Synchronization status (1 - loss; 0 -  
acquired). For ESF links multiframe synchronization and terminal frame synchronization are  
synonymous.  
SE  
LOS  
- - -  
Severely Errored Frame. This bit toggles when 2 of the last 6 received framing bits are in  
error. The framing bits monitored are the ESF framing bits for ESF links, the Ft bits for SLC-  
96 links and a combination of Ft and Fs bits for D4 links (See Framing Mode Selection Word  
- page 1 address 10H).  
4
Digital Los Of Signal. This bit goes high after the detection of a string of consecutive zeros.  
It returns low when the incoming pulse density exceeds 12.5% over a 250 ms period. The  
threshold for this condition is set by the control bit L32Z. If L32Z is set high the threshold is  
32 successive zeros. If L32Z is set low the threshold is 192 successive zeros.  
3 - 0  
Unused.  
Table 51 - Synchronization Status Word  
(Page 3, Address 10H) (T1)  
Bit  
Name  
Functional Description  
7
D4YALM D4 Yellow Alarm. This bit is set if bit position 2 of virtually every DS0 channel is a zero for a  
period of 600 milliseconds. The alarm is tolerant of errors by permitting up to 16 ones in a 48  
millisecond integration period. The alarm clears in 200 milliseconds after being removed  
from the line.  
6
D4Y48  
D4 Yellow Alarm - 48 millisecond sample. This bit is set if bit position 2 of virtually every  
DS0 channel is a zero for a period of 48 milliseconds. The alarm is tolerant of errors by  
permitting up to 16 ones in the integration period. This bit is updated every 48 milliseconds.  
5
4
SECYEL Secondary D4 Yellow Alarm. This bit is set if 2 consecutive ’1’s are received in the Sbit  
position of the 12th frame of the D4 superframe.  
ESFYEL  
ESF Yellow Alarm. This bit is set if the ESF yellow alarm 0000000011111111 is receive in  
seven or more codewords out of ten.  
3
2
BLUE  
PDV  
Blue Alarm. This bit is set if less than 6 zeros are received in a 3 millisecond window.  
Pulse Density Violation. This bit toggles if the receive data fails to meet ones density  
requirements. If RXB8ZS is set high it will toggle upon detection of 8 zeros. I RxB8ZS is  
set low it will toggle upon detection of 16 consecutive zeros on the line data, or if there  
are less than N ones in a window of 8(N+1) bits - where N = 1 to 23.  
1
0
LLED  
LLDD  
Line Loopback Enable Detect. This bit will be set when a framed or unframed repeating  
pattern of 00001 has been detected during a 48 millisecond interval. Up to fifteen errors are  
permitted per integration period.  
Line Loopback Disable Detect. This bit will be set when a framed or unframed repeating  
pattern of 001 has been detected during a 48 millisecond interval. Up to fifteen errors are  
permitted per integration period.  
Table 52 - Alarm Status Word  
(Page 3, Address 11H) (T1)  
76  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
6
1SEC  
2SEC  
One Second Timer Status. This bit changes state once every 0.5 seconds.  
Two Second Timer Status. This bit changes state once every second and is synchronous  
with the 1SEC timer.  
5
5SEC  
- - -  
Five Second Timer Status. This bit changes state once every 2.5 seconds and is  
synchronous with the 1SEC timer.  
4-0  
Unused.  
Table 53 - Timer Status Word  
(Page 3, Address 12H) (T1)  
Bit  
Name  
Functional Description  
7
RSLIP  
Receive Slip. A change of state (i.e., 1-to-0 or 0-to-1) indicates that a receive controlled  
frame slip has occurred.  
6
5
RSLPD  
RxFRM  
Receive Slip Direction. If one, indicates that the last received frame slip resulted in a  
repeated frame, i.e., the system clock (C4b) is faster than network clock (E2o). If zero,  
indicates that the last received frame slip resulted in a lost frame, i.e., system clock slower  
than network clock. Updated on an RSLIP occurance basis.  
Receive Frame Delay. The most significant bit of the Receive Slip Buffer Phase Status  
Word. If one, the delay through the receive elastic buffer is greater than one frame in length;  
if zero, the delay through the receive elastic buffer is less than one frame in length.  
4
3
- - -  
Unused.  
RxFT  
Receive Frame Toggle. This bit toggles on the falling edge of RxTS4. It is a Wink pulse.  
2-0 RxSBD2-0 Receive Sub Bit Delay. The three least significant bits of the Receive Slip Buffer Phase  
Status Word. They indicate the clock, half clock and one eight clock cycle depth of the  
phase status word sample point (bits 2, 1,0 respectively).  
Table 54 - Most Significant Phase Status Word  
(Page 3, Address 13H) (T1)  
Bit  
Name  
Functional Description  
7 - 3 RxTS4 - 0 Receive Time Slot. A five bit counter that indicates the number of time slots between the  
receive elastic buffer internal write frame boundary and the ST-BUS read frame boundary.  
The count is updated every 250 uS.  
2 - 0 RxBC2 - 0 Receive Bit Count. A three bit counter that indicates the number of STBUS bit times there  
are between the receive elastic buffer internal write frame boundary and the ST-BUS read  
frame boundary. The count is updated every 250 uS.  
Table 55 - Least Significant Phase Status Word  
(Page 3, Address 14H) (T1)  
Bit  
Name  
Functional Description  
7 - 0 RxBOM7 - 0 Received Bit Oriented Message. This register contains the eight least significant bits of the  
ESF bit oriented message codeword. The contents of this register is updated when a new bit  
- oriented message codeword has been detected in 8 out of the last ten codeword positions.  
Table 56 - Receive Bit Oriented Message  
(Page 3, Address 15H) (T1)  
77  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
LLOS  
LIU Loss of Signal indication. This bit will be high when the received signal is less than 40  
dB below the nominal value for a period of at least 1 msec. This bit will be low for normal  
operation.  
6-0  
- - -  
Unused  
Table 57 - Receive Signal Status Word  
(Page 3, Address 16H) (T1)  
Bit  
Name  
Functional Description  
7
TSLIP  
Transmit Slip. A change of state (i.e., 1-to-0 or 0-to-1) indicates that a transmit controlled  
frame slip has occurred.  
6
TSLPD Transmit Slip Direction. If one, indicates that the last transmit frame slip resulted in a  
repeated frame, i.e., the internally generated 1.544 Mhz. transmit clock is faster than the  
system clock (C4b). If zero, indicates that the last transmit frame slip resulted in a lost frame,  
i.e., the internally generated 1.544 Mhz. transmit clock is slower than network clock. Updated  
on an TSLIP occurance basis.  
5
TxSBMSB Transmit Slip Buffer MSB. The most significant bit of the phase status word. If one, the  
delay through the transmit elastic buffer is greater than one frame in length; if zero, the delay  
through the receive elastic buffer is less than one frame in length. This bit is reset whenever  
page 3 address 17H - Transmit Slip Buffer Delay - is written to.  
4 - 0  
- - -  
Unused.  
Table 58 - MSB Transmit Slip Buffer  
(Page 3, Address 17H) (T1)  
Bit  
Name  
Functional Description  
7 - 3  
TxTS4 - 0 Transmit Time Slot. A five bit counter that indicates the number of STBUS time slots  
between the transmit elastic buffer STBUS write frame boundary and the internal transmit  
read frame boundary. The count is updated every 250 uS.  
2 - 0  
TxBC2 - 0 Transmit Bit Count. A three bit counter that indicates the number of STBUS bit times  
there are between the transmit elastic buffer STBUS write frame boundary and the internal  
read frame boundary. The count is updated every 250 uS.  
Table 59 - Transmit Slip Buffer Delay  
(Page 3, Address 18H) (T1)  
Bit  
Name  
Functional Description  
7 - 0  
AP7 - 0  
Analog Peak. This status register gives the output value of an 8 bit A/D converter  
connected to a peak detector on RTIP/RRING.  
Table 60 - Analog Peak Detect  
(Page 3, Address 1DH) (T1)  
78  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7 - 0  
ESP7-0  
Analog Peak. This status register gives the output value of an 8 bit A/D converter  
connected to a peak detector on RTIP/RRING.  
Table 61 - Equalized Signal Peak Detect  
(Page 3, Address 1EH) (T1)  
Bit  
Name  
Functional Description  
7-0  
ID7-0  
ID Number. Contains device code 01111000  
Table 62 - Identification Word  
(Page 3, Address 1FH) (T1)  
79  
MT9076  
Preliminary Information  
20.1.4 Master Status 2 (Page04H) (T1)  
Address  
(A4A3A2A1A0)  
Register  
Function  
10H (Table 65)  
11H (Table 66)  
12H (Table 67)  
PRBS Error Counter  
PS7-0  
CRC Multiframe counter for PRBS  
Alarm Reporting Latch  
PSM7-0  
D4YALML, D4Y48L, SECYELL, ESFYELL,  
BLUEL, PDVL, LLEDL, LLDDL  
13H (Table 68)  
14H (Table 69)  
Framing Bit Counter  
FC7-0  
Out of Frame / Change of Frame Alignment OOF3-0/COFA3-0  
Counters  
15H (Table 70)  
16H (Table 71)  
Multiframes Out of Sync Counter  
MFOOF7-0  
Most Significant Line Code Violation Error LCV15 - LCV8  
Counter  
17H (Table 72)  
Least Significant Line Code Violation Error LCV7 - LCV0  
Counter  
18H (Table 73)  
19H (Table 74)  
1AH  
CRC- 6 Error Counter  
CRC- 6 Error Counter  
CC15-CC8  
CC7 - CC0  
Unused.  
1BH (Table 75)  
Interrupt Word Zero  
TFSYNI, MFSYNI, BIOMTI, AISI, LOSI, SEI,  
TxSLPI, RxSLPI  
1CH (Table 76)  
1DH (Table 77)  
Interrupt Word One  
Interrupt Word Two  
FEI, CRCI, YELI, COFAI, LCVI, PRBSI, PDVI  
FEO, CRCO, OOFO, COFAO, LCVO, PRBSO,  
PRBSMFO,MFOOFO  
1EH (Table 78)  
1FH (Table 79)  
Interrupt Word Three  
HDLC0I, HDLC1I, HDLC2I, LCDI, 1SECI,  
5SECI, BIOMI, SIGI  
Overflow Reporting Latch  
FEOL, CRCOL, OOFOL, COFAOL, LCVOL,  
PRBSOL, PRBSMFOL, MFOOFOL  
Table 63 - Master Status 2 (Page 4) (T1)  
Bit  
Name  
Functional Description  
7 - 0  
PS7-0  
This counter is incremented for each PRBS error detected on any of the receive channels  
connected to the PRBS error detector.  
Table 64 - PRBS Error Counter  
(Page 4, Address 10H) (T1)  
Bit  
Name  
Functional Description  
7 - 0  
PSM7-0  
This counter is incremented for each received CRC multiframe. It is cleared when the PRBS  
Error Counter is written to.  
Table 65 - CRC Multiframe Counter for PRBS  
(Page 4, Address 11H) (T1)  
80  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
D4YALML D4 Yellow Alarm Latch. This bit is set if a D4 yellow alarm is detected within a 600  
millisecond integration period. It is cleared after a read.  
6
5
4
D4Y48L  
D4 Yellow Alarm (48 milliseconds) Latch. This bit is set if a D4 yellow alarm is detected  
within a 48 millisecond integration period. It is cleared after a read.  
SECYELL Secondary D4 Yellow Alarm Latch. This bit is set if an alternate D4 (S bit in 12 the frame)  
is detected. It is cleared after a read.  
ESFYELL ESF Yellow Alarm Latch. This bit is set upon receipt of a ESF yellow alarm. It is cleared  
after a read.  
3
2
BLUEL  
PDVL  
Blue Alarm Latch. This bit is set upon receipt of a blue alarm. It is cleared after a read.  
Pulse Density Violation Latch. This bit is set upon receipt of a pulse density violation. It is  
cleared after a read.  
1
0
LLEDL  
LLDDL  
Line Loopback Enable Detect Latch. This bit is set upon receipt of a line loopback enable  
code. It is cleared after a read.  
Line Loopback Disable Detect Latch. This bit is set upon receipt of a line loopback disable  
code. It is cleared after a read.  
Table 66 - Alarm Reporting Latch  
(Page 4, Address 12H) (T1)  
Bit  
Name  
Functional Description  
7 - 0  
FC7 - 0  
Framing Bit Counter. This eight bit counter will be incremented for each error in the  
received framing pattern. In ESF mode the ESF framing bits are monitored. In D4 mode Fs  
bits may be monitored as well as Ft bits. See - Section 15.5 Framing Bit Counter. The count  
is only active if the 3VJET is in synchronization.  
Table 67 - Framing Bit Counter  
(Page 4, Address 13H) (T1)  
81  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7 - 4  
OOF3 - 0 Out Of Frame Counter. This four bit counter is incremented with every loss of receive  
frame synchronization.  
3 - 0 COFA3 - 0 Change of Frame Alignment Counter. This four bit counter is incremented if a  
resynchronization is done which results in a shift in the frame alignment position.  
Table 68 - Out Of Frame / Change of Frame Alignment Counter  
(Page 4, Address 14H) (T1)  
Bit  
Name  
Functional Description  
7 - 0 MFOOF7 - 0 Multiframes Out of Synchronization Counter. This eight bit counter will be incremented  
once for every multiframe (1.5 milliseconds in D4 mode, 3 milliseconds in ESF mode) in  
which basic frame synchronization is lost.  
Table 69 - Multiframes Out of Sync Counter  
(Page 4, Address 15H) (T1)  
Bit  
Name  
Functional Description  
7 - 0 LCV15 - 8 Most Significant Bits of the LCV Counter. The most significant eight bits of a 16 bit  
counter that is incremented once for every line code violation error received.  
A line code violation is defined as a bipolar violation that is not a part of B8ZS encoding  
when the control bit EXZ is set low. A line code violation includes both bipolar violations and  
excess zeros when EXZ is set high.  
Table 70 - Most Significant Bits of the LCV Counter  
(Page 4, Address 16H) (T1)  
Bit  
Name  
Functional Description  
7 - 0  
LCV7 - 0 Least Significant Bits of the LCV Counter. The least significant eight bits of a 16 bit  
counter that is incremented once for every line code violation error received.  
A line code violation is defined as a bipolar violation that is not a part of B8ZS encoding  
when the control bit EXZ is set low. A line code violation includes both bipolar violations and  
excess zeros when EXZ is set high.  
Table 71 - Least Significant Bits of the LCV Counter  
(Page 4, Address 17H) (T1)  
Bit  
Name  
Functional Description  
7 - 0  
CC15 - 8 CRC-6 Error Counter Bits Fifteen to Eight. These are the most significant eight bits of the  
CRC-6 error counter.  
Table 72 - CRC-6 Error Counter  
(Page 4, Address 18H) (T1)  
Bit  
Name  
Functional Description  
7 - 0  
CC7 - 0  
CRC-6 Error Counter Bits Seven to Zero. These are the least significant eight bits of the  
CRC-6 error counter.  
Table 73 - CRC-6 Error Counter  
(Page 4, Address 19H) (T1)  
82  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
TFSYNI Terminal Frame Synchronization Interrupt. When unmasked this interrupt bit goes high  
whenever a change of state of terminal frame synchronization condition exists. Reading this  
register clears this bit.  
6
MFSYNI Multiframe Synchronization Interrupt. When unmasked this interrupt bit goes high  
whenever a change of state of multiframe synchronization condition exists. Reading this  
register clears this bit.  
5
4
3
BIOMTI Bit Oiented Message Transition Interrupt. When unmasked, this interrupt goes high  
whenever a new BIOM arrives or if the current BIOM stops transmission.  
AISI  
Alarm Indication Signal Interrupt. When unmasked this interrupt bit goes high whenever a  
change of state of received all ones condition exists. Reading this register clears this bit.  
LOSI  
Loss of Signal Interrupt. When unmasked this interrupt bit goes high whenever a change of  
state of loss of signal (either analog - signal 40 dB below nominal or digital - excess  
consecutive 0’s received) condition exists. Reading this register clears this bit.  
2
1
0
SEI  
Severely Errored Frame Interrupt. When unmasked this interrupt bit goes high whenever a  
sequence of 2 framing errors out of 6 occurs. Reading this register clears this bit.  
TxSLPI Transmit SLIP Interrupt. When unmasked this interrupt goes high whenever a controlled  
frame slip occurs in the transmit elastic buffer. Reading this register clears this bit.  
RxSLPI Receive SLIP Interrupt. When unmasked this interrupt bit goes high whenever a controlled  
frame slip occurs in the receive elastic buffer. Reading this register clears this bit.  
Table 74 - Interrupt Word Zero  
(Page 4, Address 1BH) (T1)  
83  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
FEI  
Framing Bit Error Interrupt. When unmasked this interrupt bit goes high whenever an  
erroneous framing bit is detected (provided the circuit is in terminal frame sync). Reading this  
register clears this bit.  
6
5
4
CRCI  
YELI  
CRC-6 Error Interrupt. When unmasked this interrupt bit goes high whenever a local CRC-6  
error occurs. Reading this register clears this bit.  
Yellow Alarm Interrupt. When unmasked this interrupt bit goes high upon detection of a  
yellow alarm. Reading this register clears this bit.  
COFAI Change of Frame Alignment Interrupt. When unmasked this interrupt bit goes high  
whenever a change of frame alignment occurs after a reframe. Reading this register clears  
this bit.  
3
2
LCVI  
Line Code Violation Interrupt. When unmasked this interrupt bit goes high whenever a line  
code violation (excluding B8ZS encoding) is encountered. Reading this register clears this bit.  
PRBSI Psuedo Random Bit Sequence Error Interrupt. When unmasked this interrupt bit goes high  
upon detection of an error with a channel selected for PRBS testing. Reading this register  
clears this bit.  
1
0
PDVI  
Pulse Density Violation Interrupt. When unmasked this interrupt bit goes high whenever, in  
the absense of B8ZS encoding, a sequence of 16 consecutive zeros is received on the line, or  
the incoming pulse density is less than N ones in a time frame of 8(N+1) where N = 1 to 23. In  
the case of B8ZS coding, the interrupt is set upon detection of 8 consecutive zeros. Reading  
this register clears this bit.  
- - -  
Unused.  
Table 75 - Interrupt Word One  
(Page 4, Address 1CH) (T1)  
84  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
FEO  
Framing Bit Error Counter Overflow Interrupt. When unmasked this interrupt bit goes  
high whenever the framing bit error counter changes from FFH to 00H. Reading this  
register clears this bit.  
6
5
4
3
2
1
0
CRCO  
OOFO  
COFAO  
LCVO  
CRC-6 Error Counter Overflow Interrupt. When unmasked this interrupt bit goes high  
whenever the CRC-6 error counter changes from FFH to 00H. Reading this register clears  
this bit.  
Out Of Frame Counter Overflow Interrupt. When unmasked this interrupt bit goes high  
whenever the out of frame counter changes state from changes from FFH to 00H. Reading  
this register clears this bit.  
Change of Frame Alignment Counter Overflow Interrupt. When unmasked this interrupt  
bit goes high whenever the change of frame alignment counter changes from FFH to 00H.  
Reading this register clears this bit.  
Line Code Violation Counter Overflow Interrupt. When unmasked this interrupt bit goes  
high whenever the line code violation counter changes from FFH to 00H. Reading this  
register clears this bit.  
PRBSO  
Psuedo Random Bit Sequence Error Counter Overflow Interrupt. When unmasked this  
interrupt bit goes high whenever the PRBS error counter changes from FFH to 00H.  
Reading this register clears this bit.  
PRBSMFO Psuedo Random Bit Sequence Multiframe Counter Overflow Interrupt. When  
unmasked this interrupt bit goes high whenever the multiframe counter attached to the  
PRBS error counter overflows. FFH to 00H. 1 - unmasked, 0 - masked.  
MFOOFO Multiframes Out Of Sync Overflow Interrupt. When unmasked this interrupt bit goes high  
whenever the multiframes out of frame counter changes from FFH to 00H. Reading this  
register clears this bit.  
Table 76 - Interrupt Word Two  
(Page 4, Address 1DH) (T1)  
85  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
HDLC0I HDLC0 Interrupt. Whenever an unmasked HDLC0 interrupt occurs this bit goes high.  
Reading this register clears this bit.  
6
5
4
HDLC1I HDLC1 Interrupt. Whenever an unmasked HDLC1 interrupt occurs this bit goes high.  
Reading this register clears this bit.  
HDLC2I HDLC2 Interrupt. Whenever an unmasked HDLC2 interrupt occurs this bit goes high.  
Reading this register clears this bit.  
LCDI  
Loop Code Detected Interrupt. When unmasked this interrupt bit goes high whenever  
either the loop up (00001) or loop down (001) code has been detected on the line for a  
period of 48 milliseconds. Reading this register clears this bit.  
3
1SECI  
One Second Status Interrupt. When unmasked this interrupt bit goes high whenever  
the 1SEC status bit (page 3 address 12H bit 7) goes from low to high. Reading this  
register clears this bit.  
2
1
5SECI  
BIOMI  
Five Second Status Interrupt. When unmasked this interrupt bit goes high whenever  
the 5 SEC status bit goes from low to high. Reading this register clears this bit.  
Bit Oriented Message Interrupt. When unmasked this interrupt bit goes high whenever  
a pattern 111111110xxxxxx0 has been received on the FDL that is different from the last  
message. The new message must persist for 8 out the last 10 message positions to be  
accepted as a valid new message. Reading this register clears this bit.  
0
SIGI  
signaling Interrupt. When unmasked this interrupt bit goes high whenever a change of  
state (optionally debounced - see DBEn in the Data Link, signaling Control Word page 1  
address 12H) is detected in the signaling bits (AB or ABCD) pattern. Reading this register  
clears this bit.  
Table 77 - Interrupt Word Three  
(Page 4, Address 1EH) (T1)  
86  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
FEOL  
Framing Bit Error Counter Overflow Latch. This bit is set when the framing bit  
counter overflows. It is cleared after being read.  
6
5
4
3
2
1
CRCOL  
OOFOL  
COFAOL  
LCVOL  
CRC-6 Error Counter Overflow Latch. This bit is set when the crc error counter  
overflows. It is cleared after being read.  
Out Of Frame Counter Overflow Latch. This bit is set when the out of frame counter  
overflows. It is cleared after being read.  
Change of Frame Alignment Counter Overflow Latch. This bit is set when the  
change of frame alignment counter overflows. It is cleared after being read.  
Line Code Violation Counter Overflow Latch. This bit is set when the line code  
violation counter overflows. It is cleared after being read.  
PRBSOL  
Psuedo Random Bit Sequence Error Counter Overflow Latch. This bit is set when  
the PRBS error counter overflows. It is cleared after being read.  
PRBSMFOL Psuedo Random Bit Sequence Multiframe Counter Overflow Latch. This bit is set  
when the multiframe counter attached to the PRBS error counter overflows. It is cleared  
after being read  
0
MFOOFOL  
Multiframes Out Of Sync Overflow Latch. This bit is set when the multiframes out of  
sync counter overflows. It is cleared after being read.  
Table 78 - Overflow Reporting Latch  
(Page 4, Address 1FH) (T1)  
87  
MT9076  
Preliminary Information  
20.1.5 Per Channel Transmit signaling (Pages 5 and 6) (T1)  
Page 05H, addresses 10000 to 11111, and page 06H addresses 10000 to 10111 contain the Transmit signaling  
Control Words for DS1 channels 1 to 16 and 17 to 24 respectively. Table 80 illustrates the mapping between the  
addresses of these pages and the DS1 channel numbers. Control of these bits for any one channel is through  
the processor or controller port when the Per Time Slot Control bit RPSIG bit is high. Table 81 describes bit  
allocation within each of these registers.  
Page 5 Address:  
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10 11 12 13 14 15  
Equivalent DS1  
channel  
10 11 12 13 14 15 16  
Page 6 Address:  
0
1
2
3
4
5
6
7
8
x
9
x
10 11 12 13 14 15  
Equivalent DS1  
channel  
17 18 19 20 21 22 23 24  
x
x
x
x
x
x
Table 79 - Page 5, 6 Address Mapping to DS1 Channels (T1)  
Bit  
Name  
Functional Description  
7 - 4  
3
- - -  
Unused.  
Transmit signaling Bits A for Channel n. Where signaling is enabled, these bits are  
A(n)  
transmitted in bit position 8 of the 6th DS1 frame (within the 12 frame superframe structure  
for D4 superframes and the 24 frame structure for ESF superframes).  
2
1
0
B(n)  
C(n)  
D(n)  
Transmit signaling Bits B for Channel n. Where signaling is enabled, these bits are  
transmitted in bit position 8 of the 12th DS1 frame (within the 12 frame superframe structure  
for D4 superframes and the 24 frame structure for ESF superframes).  
Transmit signaling Bits C for Channel n. Where signaling is enabled, these bits are  
transmitted in bit position 8 of the 18th DS1 frame within the 24 frame structure for ESF  
superframes. In D4 mode these bits are unused.  
Transmit signaling Bits D for Channel n. Where signaling is enabled, these bits are  
transmitted in bit position 8 of the 24th DS1 frame within the 24 frame structure for ESF  
superframes. In D4 mode these bits are unused.  
Table 80 - Transmit Channel Associated signaling (T1) (Pages 5,6)  
Serial per channel transmit signaling control through CSTi is selected when the Per Time Slot Control bit  
RPSIG bit is low. Table 82 describes the bit allocation within each of the 24 active ST-BUS time slots of CSTi.  
88  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7 - 4  
A(n),  
B(n)  
C(n),  
D(n)  
Transmit signaling Bits for Channel n. When control bit MSN = 1 and RPSIG = 1 this  
nibble is used. For ESF links these 4 bits are transmitted on the associated DS1 channel  
(see table 8) in frames 6, 12, 18 and 24. For D4 links bits A are transmit on the associated  
Ds1 channel of frame 6 and bits B are transmit on the associated DS1 channel of frame 12.  
For D4 links bits C and D are unused.  
3 - 0  
A(n),  
B(n),  
C(n),  
D(n)  
Transmit signaling Bits for Channel n. When control bit MSN = 0 and RPSIG = 1 this  
nibble is used. For ESF links these 4 bits are transmitted on the associated DS1 channel  
(see table 8) in frames 6, 12, 18 and 24. For D4 links bits A are transmit on the associated  
Ds1 channel of frame 6 and bits B are transmit on the associated DS1 channel of frame 12.  
For D4 links bits C and D are unused.  
Table 81 - T1 / Transmit Channels Usage - CSTi  
NOTE: This table illustrates bit mapping on the serial input stream - it does not refer to an internal register.  
89  
MT9076  
Preliminary Information  
20.2  
Per Time Slot Control Words (Pages 7 and 8) (T1)  
The control functions described by Table 80 are repeated for each DS1 time slot. Page 7 addresses 10000 to  
11111 correspond to DS1 time slot 1 to 16, while page 8 addresses 10000 to 10111 correspond to time slots  
17 to 24. Table 83 illustrates the mapping between the addresses of these pages and the DS1 channel  
numbers.  
Page 7 Address:  
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10 11 12 13 14 15  
Equivalent DS1  
channel  
10 11 12 13 14 15 16  
Page 8 Address:  
0
1
2
3
4
5
6
7
8
x
9
x
10 11 12 13 14 15  
Equivalent DS1  
channel  
17 18 19 20 21 22 23 24  
x
x
x
x
x
x
Table 82 - Pages 7 and 8 Address Mapping to DS1 Channels  
Functional Description  
Bit  
Name  
7
TXMSG Transmit Message Mode. If high, the data contained in the Transmit Message Register  
(address 18H, page 1) is transmitted in the corresponding DS1 time slot. If zero, the data on  
DSTi is transmitted on the corresponding DS1 time slot.  
6
5
4
3
PCI  
Per Channel Inversion. When set high the data for this channel sourced from DSTi is  
inverted before being transmit onto the equivalent DS1 channel; the data received from the  
incoming DS1 channel is inverted before it emerges from DSTo.  
RTSL  
LTSL  
TTST  
Remote Time Slot Loopback. If one, the corresponding DS1 receive time slot is looped to  
the corresponding DS1 transmit time slot. This received time slot will also be present on  
DSTo. If zero, the loopback is disabled.  
Local Time Slot Loopback. If one, the corresponding transmit time slot is looped to the  
corresponding receive time slot. This transmit time slot will also be present on the transmit  
DS1 stream. If zero, this loopback is disabled.  
Transmit Test. If one, a test signal, either digital milliwatt (when control bit ADSEQ is one) or  
15  
PRBS (2 -1) (ADSEQ is zero), will be transmitted in the corresponding DS1 time slot. More  
than one time slot may be activated at once. If zero, the test signal will not be connected to  
the corresponding time slot.  
2
RTST  
Receive Test. If one, the corresponding DSTo timeslot will be used for testing. If control bit  
ADEQ is one, a digital milliwatt will be transmitted in the corresponding DSTo channel. If  
control bit ADSEQ is zero, the receive channel will be connected to the PRBS detector (2 -  
15  
1).  
1
0
RPSIG  
CC  
Serial Signaling Enable. If set low, the transmit signaling buffer for the equivalent DS1  
channel will be sourced from the ST-BUS channel on CSTi associated with it. If set high the  
transmit signaling RAM must be programmed via the microport.  
Clear Channel. When set high no robbed bit signaling is inserted in the equivalent transmit  
DS1 channel. When set low robbed bit signaling is included in every 6th channel.  
Table 83 - Per Time Slot Control Words (Pages 7 and 8) (T1)  
90  
Preliminary Information  
MT9076  
20.2.1 Per Channel Receive signaling (T1 and E1 mode) (Pages 9 and 0AH)  
Page 09H, addresses 10000 to 11111, and page 1AH addresses 10000 to 10111 contain the Receive signaling  
Control Words for DS1 channels 1 to 16 and 17 to 24 respectively. Table 85 illustrates the mapping between the  
addresses of these pages and the DS1 channel numbers. Table 86 describes bit allocation within each of these  
registers.  
Page 9 Address:  
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10 11 12 13 14 15  
Equivalent DS1  
channel  
10 11 12 13 14 15 16  
Page A Address:  
0
1
2
3
4
5
6
7
8
x
9
x
10 11 12 13 14 15  
Equivalent DS1  
channel  
17 18 19 20 21 22 23 24  
x
x
x
x
x
x
Table 84 - Page 9, A Address Mapping to DS1 Channels (T1)  
Bit  
Name  
Functional Description  
7 - 4  
3
- - -  
Unused  
A(n)  
Receive signaling Bits A for Channel n. These bits are extracted from bit position 8 of  
every channel in received frame 6 (within the 12 frame superframe structure for D4  
superframes and the 24 frame structure for ESF superframes). The bits may be debounced  
for 6 to 9 milliseconds where control bit DBNCE is set high.  
3
2
0
B(n)  
C(n)  
D(n)  
Receive signaling Bits B for Channel n. These bits are extracted from bit position 8 of  
every channel in received frame 12 (within the 12 frame superframe structure for D4  
superframes and the 24 frame structure for ESF superframes). The bits may be debounced  
for 6 to 9 milliseconds where control bit DBNCE is set high.  
Receive signaling Bits C for Channel n. These bits are extracted from bit position 8 of  
every channel in received frame 18 within the 24 frame structure for ESF superframes. The  
bits reported may be debounced for 6 to 9 milliseconds where control bit DBNCE is set high.  
In D4 mode these bits are unused.  
Receive signaling Bits D for Channel n. These bits are extracted from bit position 8 of  
every channel in received frame 24 within the 24 frame structure for ESF superframes. The  
bits reported may be debounced for 6 to 9 milliseconds where control bit DBNCE is set high.  
In D4 mode these bits are unused.  
Table 85 - Receive Channel Associated signaling (Pages 9 and A) (T1)  
91  
MT9076  
Preliminary Information  
20.3  
E1 Mode  
20.3.1 Master Control 1 (Page 01H) (E1)  
Address  
Register  
Function  
(A4A3A2A1A0)  
10H (Table 88)  
Mode Selection Control Word  
ASEL, CRCM, AUTC, ARAI, AUTY, CSYN,  
REFRM, MFRF  
11H (Table 89)  
12H (Table 90)  
13H (Table 91)  
14H (Table 92)  
15H (Table 93)  
Transmit Alarm Control Word  
TS0 Control Word  
TE, TAIS16, TxAO, Einv  
EXZ, SaBorNi, RxTRSP, TxTRSP, TIU1,TIU0  
TMA1-4,X1,Y, X2, X3  
Transmit Multiframe Alignment Signal  
Interrupt and signaling Control Word  
Coding and Loopback Control Word  
DSToEn, CSToEn, TxCCS, DBNCE, MSN  
RxHDB3, MLBK, TxHDB3, DLBK, RLBK,  
SLBK, PLBK  
16H (Table 94)  
17H (Table 95)  
18H (Table 96)  
19H (Table 97)  
Non Frame Alignment Control Word  
Multiframe and Data Link Selection  
Transmit Message Word  
TALM, TNU4-8  
MFSEL, NBTB, Sa4-Sa8  
TXM7-0  
Error Insertion Word  
BPVE, CRCE, FASE, NFSE, LOSE, PERR,  
L32Z, LOS/LOF  
1AH (Table 98)  
1BH (Table 99)  
signaling Control Word  
RST, SPND, INTA, CNTCLR, SAMPLE, OOFP  
Interrupt Mask Word Zero  
SYNIM, MFSYIM, CSYNIM, AISIM, LOSIM,  
CEFIM, YMI, SLPIM  
1CH (Table 100)  
1DH (Table 101)  
1EH (Table 102)  
1FH (Table 103)  
Interrupt Mask Word One  
Interrupt Mask Word Two  
Interrupt Mask Word Three  
LIU Receiver Word  
FERIM, CRCIM, EBIM, AIS16IM, LCVIM,  
PRBSIM, AUXPIM & RAIM  
FEOM, CRCOM, EOM, LCVOM, PRBSOM,  
PRBSMFOM, SaIM  
HDLC0IM, HDLC1IM, HDLC2IM, JAIM,  
1SECIM, 5SECIM, RCRIM, SIGIM  
NRZ, RxA1-0, RxEQ2-0  
Table 86 - Master Control 1 (Page 1) (E1)  
92  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
ASEL  
AIS Select. This bit selects the criteria on which the detection of a valid Alarm Indication  
Signal (AIS) is based. If zero, the criteria is less than three zeros in a two frame period (512  
bits). If one, the criteria is less than three zeros in each of two consecutive double-frame  
periods (512 bits per double frame).  
6
CRCM  
CRC-4 Modification. If one activates the CRC-4 remainder modification function when the  
device is in transparent mode. The received CRC-4 remainder is modified to reflect only the  
changes in the transmit DL. If zero, time slot zero data from DSTi will not be modified in  
transparent mode.  
5
4
AUTC  
ARAI  
Automatic CRC-interworking. If zero, automatic CRC-interworking is activated. If one it is  
deactivated. See Framing Algorithm for a detailed description.  
Automatic Remote Alarm Indication. if zero, the Remote Alarm Indication bit (the  
A bit) will function automatically. That is, RAI=1 when basic synchronization has  
been acquired. And, RAI=0 when basic synchronization has not been acquired. if  
one, the remote alarm indication bit is controlled through the TALM bit of the transmit Non-  
Frame Alignment Control Word.  
3
2
AUTY  
CSYN  
Automatic Y-Bit Operation. If zero, the Y-bit of the transmit multiframe alignment signal will  
report the multiframe alignment status to the far end i.e., zero - multiframe alignment  
acquired, one - lost. If one, the Y-bit is under the manual control of the Transmit Multiframe  
Alignment Control Word.  
CRC-4 Synchronization. If zero, basic CRC-4 synchronization processing is activated, and  
the TIU0 Bit and the TIU1 bit programming will be overwritten. If one, CRC-4 synchronization  
is disabled, the first bits of channel 0 are used as international use bits and are programmed  
by the TIU0 and TIU1.  
1
0
REFRM  
MFRF  
Reframe. If one for at least one frame, and then cleared, the device will initiate a search for a  
new basic frame position. Reframing function is activated on the one to zero transition of the  
REFRM bit.  
Multiframe Reframe. If one, for at least one frame, and then cleared the 3VJET will initiate a  
search for a new signaling multiframe position. Reframing function is activated on the one to  
zero transition of the MFRM bit.  
Table 87 - Mode Selection Control Word (E1)  
(Page 1, Address 10H)  
93  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
Reserved. Must be kept at 0 for normal operation.  
7
6
- -  
TE  
Transmit E bits. When zero and CRC-4 synchronization is achieved, the E-bits transmit the  
received CRC-4 comparison results to the distant end of the link, as per G.703. That is,  
when zero and CRC-4 synchronization is lost, the transmit E-bits will be zero. If one, and  
CRC-4 synchronization is lost the transmit E-bits will be one.  
5
4
3
TAIS16 Transmit AIS Time Slot 16. If one, an all ones signal is transmitted in time slot 16. If zero,  
time slot functions normally.  
TxAO  
Einv  
Transmit All Ones. When low, this control bit forces a framed or unframed (depending on  
the state of Transmit Alarm Control bit 0) all ones to be transmit at TTIP and TRING.  
Ebit Error Inversion. When zero, received Ebits set to zero are counted in the Ebit error  
counter and interrupt generator. When one, Ebits set to one are counted in the Ebit error  
counter and interrupt generator.  
2-0  
- - -  
Unused  
Table 88 - Transmit Alarm Control Word (E1)  
(Page 1, Address 11H)  
Bit  
Name  
Functional Description  
7
6
5
- - -  
- - -  
Unused.  
Unused.  
EXZ  
Excess Zeros. Setting this bit causes each occurance of received excess zeros to  
increment the Line Code Violation Counter. Excess zeros are defined as 4 or more  
successive zeros for HDB3 encoded data, or 16 or more successive zeros for non-HDB3  
encoded data.  
4
3
SaBorNi Sa Bit or Nibble. Set this bit to determine the criteria for interrupts due to transitions of Sa  
bits. If set to one, a change of state of any Sa bit is the criteria. If set to zero, a change of  
state of an Sa nibble is the criteria. Note that the selected event can only trigger an interrupt  
if the interrupt mask bit SaIM is set high in the Interrupt Mask Word Two - page 1 address  
1DH bit 0.  
RxTRSP Receive Transparent Mode. When this bit is set to one, the framing function is disabled on  
the receive side. Data coming from the receive line passes through the slip buffer and drives  
DSTo with an arbitrary alignment. When zero, the receive framing function operates  
normally.  
2
1
TxTRSP Transmit Transparent Mode. If one, the MT9076 is in transmit transparent mode. No  
framing or signaling is imposed on the data transmit from DSTi onto the line. If zero, it is in  
termination mode.  
TIU1  
Transmit International Use One. When CRC-4 operation is disabled (CSYN=1), this bit is  
transmit on the PCM 30 2048 kbit/sec. link in bit position one of time-slot zero of non-frame-  
alignment frames. It is reserved for international use and should normally be kept at one. If  
CRC processing is used, i.e., CSYN =0, this bit is ignored.  
0
TIU0  
Transmit International Use Zero. When CRC-4 operation is disabled (CSYN=1), this bit is  
transmit on the PCM 30 2048 kbit/sec. link in bit position one of time-slot zero of frame-  
alignment frames. It is reserved for international use and should normally be kept at one. If  
CRC processing is used, i.e., CSYN =0, this bit is ignored.  
Table 89 - TS0 Control Word (E1)  
(Page 1, Address 12H)  
94  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7-4  
TMA1-4 Transmit Multiframe Alignment Bits One to Four. These bits are transmitted on the PCM  
30 2048 kbit/sec. link in bit positions one to four of time slot 16 of frame zero of every  
signaling multiframe. These bits are used by the far end to identify specific frames of a  
signaling multiframe. TMA1-4 = 0000 for normal operation.  
3
2
X1  
This bit is transmitted on the PCM 30 2048 kbit/sec. link in bit position five of time slot 16 of  
frame zero of every multiframe. X1 is normally set to one.  
Y
This bit is transmitted on the PCM 30 2048 kbit/sec. link in bit position six of time slot 16 of  
frame zero of every multiframe. It is used to indicate the loss of multiframe alignment to the  
remote end of the link. If one - loss of multiframe alignment; if zero - multiframe alignment  
acquired. This bit is ignored when AUTY is zero (page 01H, address 11H).  
1, 0  
X2, X3 These bits are transmitted on the PCM 30 2048 kbit/sec. link in bit positions seven and eight  
respectively, of time slot 16 of frame zero of every multiframe. X2 and X3 are normally set to  
one.  
Table 90 - Transmit Multiframe Alignment Signal (E1)  
(Page 1, Address 13H)  
Bit  
Name  
Functional Description  
7
6
5
DSToEn DSTo Enable. If zero pin DSTo is tristate. If set the pin DSTo is enabled.  
CSToEn CSTo Enable. If zero pin CSTo is tristate. If set the pin CSTo is enabled.  
TxCCS Transmit Common Channel signaling. If one, the transmit channel 16 of the device is in  
common channel signaling (CCS) mode. If zero, it is in Channel Associated signaling (CAS)  
mode, data for channel 16 is sourced from the internal transmission ABCD register.  
4
3
DBNCE Debounce Select. This bit selects the debounce period (1 for 14 msec.; 0 for no debounce).  
Note: there may be as much as 2 msec. added to this duration because the state change of  
the signaling equipment is not synchronous with the PCM 30 signaling multiframe.  
MSN  
Most Significant signaling Nibble. If one, the CSTo and CSTi channel associated signaling  
nibbles will be valid in the most significant portion of each ST-BUS time slot. If zero, the CSTo  
and CSTi channel associated signaling nibbles will be valid in the least significant portion of  
each ST-BUS time slot.  
2,1,0  
- - -  
Unused.  
Table 91 - Interrupt and signaling Control Word (E1)  
(Page 1, Address 14H)  
95  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
RxHDB3 High Density Bipolar 3 Encoding. If one, HDB3 encoding is enabled in the receive direction.  
If zero, AMI signal without HDB3 encoding is received.  
6
5
MLBK  
Metallic Loopback. If one, then the external RRTIP and RRING signals are isolated from the  
receiver, and TTIP and TRING are internally connected to the receiver analog input instead. If  
zero, metallic loopback is disabled.  
TxHDB3 High Density Bipolar 3 Encoding. If one, HDB3 encoding is enabled in the transmit  
direction. If zero, AMI signal without HDB3 encoding is transmitted. HDB3 is always decoded  
in the receive direction.  
4
3
- - -  
Unused.  
DLBK  
Digital Loopback. If one, then the digital stream to the transmit LIU is looped back in place of  
the digital output of the receive LIU. Data coming out of DSTo will be a delayed version of  
DSTi. If zero, this feature is disabled.  
2
1
0
RLBK  
SLBK  
PLBK  
Remote Loopback. If one, then all bipolar data received on RRTIP/RRING are directly routed  
to TTIP/TRING on the PCM 30 side of the MT9076. If zero, then this feature is disabled.  
ST-BUS Loopback. If one, then all time slots of DSTi are connected to DSTo on the ST-BUS  
side of the MT9076. If zero, then this feature is disabled. See Loopbacks section.  
Payload Loopback. If one, then all time slots received on RTIP/RRING are connected to  
TTIP/TRING on the ST-BUS side of the MT9076 (this excludes time slot zero). If zero, then  
this feature is disabled.  
Table 92 - Coding and Loopback Control Word (E1)  
(Page 1, Address 15H)  
Bit  
Name  
Functional Description  
7 - 6  
5
- - -  
Unused.  
TALM Transmit Remote Alarm. This bit is transmitted on the PCM 30 2048 kbit/sec. link in bit  
position three (A bit) of time slot zero of NFAS frames. It is used to signal an alarm to the  
remote end of the PCM 30 link (one - alarm, zero - normal). This control bit is ignored  
when ARAI is zero (page 01H, address 10H).  
4-0  
TNU4-8 Transmit National Use Four to Eight (Sa4 - Sa8). These bits are transmitted on the  
PCM 30 2048 kbit/sec. link in bit positions four to eight of time slot zero of the NFA frame,  
if selected by Sa4 - Sa8 control bits of the DL selection word (page 01H, address 10H).  
Table 93 - Non Frame Alignment Control Word (E1)  
(Page 1, Address 16H)  
96  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
6
- - -  
Unused  
MFSEL Multiframe Select. This bit determines which receive multiframe signal (CRC-4 or signaling)  
the RxMF (pin 42 in PLCC, 23 in MQFP) signal is aligned with. If zero, RxMF is aligned with  
the receive signaling multiframe. If one, RxMF is aligned with the receive CRC-4 multiframe.  
5
NBTB  
National Bit Transmit Buffer. If one, the transmit NFAS signal originates from the transmit  
national bit buffer page 0EH; if zero, the transmit NFAS signal originates from the TNU4-8 bits  
of page 1 address 16H.  
4-0  
Sa4-Sa8 National Bit Data Link Select A one selects the corresponding Sa bits of the NFA signal for  
4, 8, 12, 16 or 20 kbits/sec. data link channel. Data link (DL) selection will function in  
termination mode only; in transmit transparent mode Sa4 is automatically selected - see  
TxTRSP control bit of page 01H, address 11H. If zero, the corresponding bits of transmit non-  
frame alignment signal are programmed by the Non-Frame Alignment Control Word (page  
01H, address 12H).  
Table 94 - Multiframe and Data Link Selection (E1)  
(Page 1, Address 17H)  
Bit  
Name  
Functional Description  
7-0  
TxM7-0 Transmit Message Bits 7 - 0. The contents of this register are transmit into those outgoing  
DS1 channels selected by the Per Time Slot Control registers.  
Table 95 - Transmit Message Word (E1)  
(Page 1, Address 18H)  
97  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
BPVE  
Bipolar Violation Error Insertion. A zero to one transition of this bit inserts a single  
bipolar violation error into the transmit PCM 30 data. A one, zero or one to zero  
transition has no function.  
6
5
CRCE  
FASE  
CRC-4 Error Insertion. A zero to one transition of this bit inserts a single CRC-4 error  
into the transmit PCM 30 data. A one, zero, or one to zero transition has no function.  
Frame Alignment Signal Error Insertion. A zero to one transition of this bit inserts a  
single error into the time slot zero frame alignment signal of the transmit PCM 30 data.  
A one, zero, or one to zero transition has no function.  
4
3
NFSE  
LOSE  
Non-frame Alignment Signal Error Insertion. A zero to one transition of this bit  
inserts a single error into bit two of the time slot zero non-frame alignment signal of the  
transmit PCM 30 data. A one, zero, or one to zero transition has no function.  
Loss of Signal Error Insertion. If one, the MT9076 transmits an all zeros signal (no  
pulses) in every PCM 30 time slot. When HDB3 encoding is activated no violations are  
transmitted. If zero, data is transmitted normally.  
2
1
0
PERR  
L32Z  
Payload Error Insertion. A zero to one transition of this bit inserts a single error in the  
transmit payload. A one, zero, or one to zero transition has no function.  
Digital Loss of Signal Selection. If one, the threshold for digital loss of signal is 32  
successive zeros. If zero, the threshold is set to 192 successive zeros.  
LOS/LOF Loss of Signal or Loss of Frame Selection. If one, pin LOS (pin 61 in PLCC, 57 in  
MQFP) will go high when a loss of signal state exits. A loss of signal is defined as either  
receipt of a signal attenuated below the analog loss of signal threshold (selectable as  
20 dB or 40 dB below nominal) or receipt of 256 consecutive 0’s. If low, pin LOS will go  
high when either a loss of signal or a loss of basic frame alignment state exits (bit SYNC  
on page 03H address 10H is zero).  
Table 96 - Error Insertion Word (E1)  
(Page 1, Address 19H)  
98  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
RST  
Reset. When this bit is changed from zero to one the device will reset to its default mode.  
See the Reset Operation section for the default settings.  
6
SPND  
INTA  
Suspend Interrupts. If one, the IRQ output (pin 12 in PLCC, 85 in MQFP) will be in a  
high-impedance state and all interrupts will be ignored. If zero, the IRQ output will function  
normally.  
5
4
3
Interrupt Acknowledge. A zero-to-one or one-to-zero transition will clear any pending  
interrupt and make IRQ high.  
CNTCLR Counter Clear. If one, all status counters are cleared and held low. Zero for normal  
operation.  
SAMPLE One Second Sample. Setting this bit causes the error counters (change of frame  
alignment, loss of frame alignment, lcv errors, crc errors, severely errored frame events  
and multiframes out of sync) to be updated on one second intervals coincident with the  
one second timer (status page 3 address 12H bit 7).  
2
OOFP  
Out of Frame Pause. If set high, this bit will suspend operation of the Line Code VIolation  
Counter during an out - of - frame condition; upon achieving terminal frame  
synchronization the counter will resume normal operation. If set low, the Line Code  
Violation counter will continue to count errors even if terminal frame synchronization is  
lost.  
1
0
- -  
Reserved. Set low for normal operation.  
D20  
Double 20. Set low for normal operation. Set high to double clock speed in the HDLC to  
speed up memory accesses from 160ns between consecutive reads/writes to 80ns  
between consecutive reads/writes.  
Table 97 - Signaling Control Word (E1)  
(Page 1, Address 1AH)  
99  
MT9076  
Preliminary Information  
Bit  
Name  
SYNIM  
Functional Description  
7
Synchronization Interrupt Mask. When unmasked (SYNI = 1) an interrupt is initiated  
whenever a change of state of loss of basic frame synchronization condition exists. If 1-  
unmasked, 0 - masked.  
6
5
MFSYIM Multiframe Synchronization Interrupt Mask. When unmasked (MFSYI = 1), an  
interrupt is initiated whenever a change of state of multiframe synchronization exists. If  
1- unmasked, 0 - masked.  
CSYNIM CRC-4 Multiframe Synchronization Interrupt Mask. When unmasked (CSYNI = 1), an  
interrupt is initiated whenever a change of state of CRC-4 multiframe synchronization  
exists. If 1- unmasked, 0 - masked.  
4
3
AISIM  
Alarm Indication Signal Interrupt Mask. When unmasked (AISI = 1) a change of state  
of received AIS will initiate an interrupt. If 1- unmasked, 0 - masked.  
LOSIM  
Loss of Signal Interrupt Mask. When unmasked this interrupt bit goes high whenever a  
change of state of loss of signal (either analog - received signal 20 or 40 dB below  
nominal or digital - 256 consecutive 0’s received) condition exists. If 1- unmasked, 0 -  
masked.  
2
1
0
CEFIM  
YIM  
Consecutively Errored FASs Interrupt Mask. When unmasked an interrupt is initiated  
when two consecutive errored frame alignment signals are received. If 1 - unmasked, 0 -  
masked.  
Remote signaling Multiframe Alarm Interrupt Mask. When unmasked (YI = 1), an  
interrupt is initiated whenever a change of state of when a remote signaling multiframe  
alarm signal is received. If 1- unmasked, 0 - masked.  
SLPIM  
SLIP Interrupt Mask. When unmasked (SLPI = 1), an interrupt is initiated when a  
controlled frame slip occurs. If 1- unmasked, 0 - masked.  
Table 98 - Interrupt Mask Word Zero (E1)  
(Page 1, Address 1BH)  
Bit  
Name  
Functional Description  
7
FERIM Frame Error Interrupt Mask. When unmasked (FERI = 1), an interrupt is initiated when an  
error in the frame alignment signal occurs. If 1- unmasked, 0 - masked.  
6
5
4
3
2
1
0
CRCIM CRC-4 Error Interrupt Mask. When unmasked an interrupt is initiated when a local CRC-4  
error occurs. If 1 - unmasked, 0 - masked.  
EBIM  
Receive E-bit Interrupt Mask. When unmasked an interrupt is initiated when a receive E-bit  
indicates a remote CRC-4 error. If 1 - unmasked, 0 - masked.  
AIS16IM Channel 16 Alarm Indication Signal Interrupt Mask. When unmasked (AIS16I = 1), a  
received AIS16 will initiate an interrupt. If 1- unmasked, 0 - masked.  
LCVIM Line Code Violation Interrupt Mask. When unmasked an interrupt is initiated when a line  
code violation error occurs. If 1 - unmasked, 0 - masked.  
PRBSIM PRBS Interrupt Mask. When unmasked (PRBSI = 1), an interrupt is initiated on a single  
PRBS detection error. If 1- unmasked, 0 - masked.  
AUXPIM Auxiliary Pattern Interrupt Mask. When unmasked (AUXPI = 1), an interrupt is initiated  
when the AUXP status bit of page 03H, address 15H goes high. If 1- unmasked, 0 - masked.  
RAIIM  
Remote Alarm Indication Interrupt Mask. When unmasked (RAII = 1) a received RAI will  
initiate an interrupt. If 1- unmasked, 0 - masked.  
Table 99 - Interrupt Mask Word One (E1)  
(Page 1, Address 1CH)  
100  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
FEOM  
Frame Alignment Signal Error Counter Overflow Interrupt Mask. When unmasked an  
interrupt is initiated when the frame alignment signal error counter overflows. If 1 -  
unmasked, 0 - masked.  
6
CRCOIM  
CRC-4 Error Counter Overflow Interrupt Mask. When unmasked an interrupt is initiated  
when the CRC-4 error counter overflows. If 1 - unmasked, 0 - masked.  
5
4
- - -  
Unused.  
EBOIM  
Receive E-bit Counter Overflow Interrupt Mask. When unmasked an interrupt is  
initiated when the E-bit error counter overflows. If 1 - unmasked, 0 - masked.  
3
2
1
0
LCVCOM Line Code Violation Counter Overflow Interrupt Mask. When unmasked (LCVO = 1),  
an interrupt is initiated when the line code violation error counter changes form FFFFH to  
0H. If 1- unmasked 0 - masked.  
PRBSOM PRBS Counter Overflow Interrupt Mask. When unmasked (PRBSO = 1), an interrupt is  
initiated on overflow of PRBS counter (page 04H, address 10H) from FFH to 0H. If 1-  
unmasked 0 - masked.  
PRBSMFOM PRBS MultiFrame Counter Overflow Interrupt Mask. When unmasked an interrupt will  
be generated whenever the multiframe counter attached to the PRBS error counter  
overflows. If 1- unmasked 0 - masked.  
SaIM  
Sa Bits Interrupt Masks. When unmasked an interrupt will be triggered by either a  
change of state of any of the received Sa bits Sa5, Sa6, Sa7 or Sa8 (SaBorNi = 1) or a  
change of state of any of the received Sa nibbles (SaBorNi = 0). The control bit SaBorNi is  
located in page 1 address 12H bit 4. If 1- unmasked 0 - masked.  
Table 100 - Interrupt Mask Word Two (E1)  
(Page 1, Address 1DH)  
101  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
HDLC0IM HDLC0 Interrupt Mask. When unmasked an interrupt is triggered by an unmasked event in  
HDLC0. If 1 - unmasked, 0 - masked.  
6
5
4
HDLC1IM HDLC1 Interrupt Mask. When unmasked an interrupt is triggered by an unmasked event in  
HDLC1. If 1 - unmasked, 0 - masked.  
HDLC2IM HDLC2 Interrupt Mask. When unmasked an interrupt is triggered by an unmasked event in  
HDLC2. If 1 - unmasked, 0 - masked.  
JAIM  
Jitter Attenuation Interrupt Mask. When unmasked, an interrupt will be initiated when the  
jitter attenuator FIFO comes within four bytes of an overflow or underflow condition. If 1 -  
unmasked, 0 - masked.  
3
2
1
0
1SECIM One Second Status Interrupt Mask. When unmasked (1SECI = 1), an interrupt is initiated  
when the 1SEC status bit changes from zero to one. If 1- unmasked, 0 - masked.  
5SECIM Five Second Status Interrupt Mask. When unmasked (5SECI = 1), an interrupt is initiated  
when the 5SECI status bit changes from zero to one. If 1- unmasked, 0 - masked.  
RCRIM  
SIGIM  
RCRI Interrupt Mask. Whenever an unmasked (RCRI=1), an interrupt is initiated when RCR  
(remote alarm & CRC-4 error) status bit changes from zero to one. If 1- unmasked, 0 - masked.  
signaling (CAS) Interrupt Mask. When unmasked and any of the receive ABCD bits of any  
channel changes state an interrupt is initiated. If 1 - unmasked, 0 - masked..  
Table 101 - Interrupt Mask Word Three (E1)  
(Page 1, Address 1EH)  
Bit  
Name  
Functional Description  
7
NRZ  
NRZ Format Selection. Only used in the digital framer only mode (LIU is  
disabled). A one sets the MT9076 to accept a unipolar NRZ format input  
stream on RxA as the line input, and to transmit a unipolar NRZ format  
stream on TxB. A zero causes the MT9076 to accept a complementary pair  
of dual rail inputs on RxA/RxA and to transmit a complementary pair of dual  
rail outputs on TxA/TxB.  
6 - 4  
3-2  
- - -  
Reserved. Set this bit low for normal operation.  
RxA1-0  
Automatic Receive Equalizer Control. If either bit is the receive equalizer is  
turned on and will compensate for loop length automatically. The control bits  
RxEQ2-0 will be ignored. The combinations 11, 10 and 01 decode three  
different equalization algorithms. If both are set low (00) then equalization will  
be actived using the control bits RxEQ2-0.  
2-0  
RxEQ2-0  
Receive Equalization Select. Setting these pins forces a level of  
equalization of the incoming line data.  
RES2 RES1 RES0 Receive Equalization  
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
none  
8 dB  
16 dB  
24 dB  
32 dB  
40 dB  
48 dB  
reserved  
These settings have no effect if either of RxA1 and RxA0 are set to one.  
Table 102 - LIU Receive Word (E1)  
(Page 1, Address 1FH)  
102  
Preliminary Information  
MT9076  
20.4  
Master Control 2 (Page-2)  
20.4.1 Master Control 2 (Page 02H) (E1)  
Register  
Names  
Address  
(A4A3A2A1A0)  
10H (Table 105) Configuration Control Word  
11H (Table 106) LIU Tx Word  
T1/E1, TxEN, LIUEn, ELOS, Tx8KEN, ADSEQ  
WR, Pk2, Pk1, CPL, TxLB2-0  
12H  
Reserved  
Set all bits to zero for normal operation.  
13H (Table 107) Jitter Attenuator Control Word  
JFC, JFD2-JFD0, JACL  
14H  
15H  
Reserved  
Reserved  
Set all bits to zero for normal operation.  
Set all bits to zero for normal operation.  
16H (Table 108) Equalizer High Threshold  
17H (Table 109) Equalizer Low Threshold  
18H (Table 110) Serial Bit Rate  
EHT7-0  
ELT7-0  
IMA,8Men,8MTS1-0  
En, SaSEL, CH4-0  
En, CH4-0  
En, CH4-0  
CP6-0  
19H (Table 111) HDCL0 Select  
1AH (Table 112) HDCL1 Select  
1BH (Table 113) HDLC2 Select  
1CH(Table 114) Custom Pulse Word 1  
1DH(Table 115) Custom Pulse Word 2  
1EH (Table 116) Custom Pulse Word 3  
1FH (Table 117) Custom Pulse Word 4  
CP6-0  
CP6-0  
CP6-0  
Table 103 - Master Control 2 (Page 02H) (E1)  
103  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
6
5
T1/E1  
- -  
E1 mode selection. when this bit is one, the device is in E1 mode.  
Reserved. Must be kept at 0 for normal operation.  
TxEN  
Transmit Enable. Setting this bit low turns off the TTIP and TRING output line drivers.  
Setting this bit high enables them.  
4
LIUEn  
LIU Enable.Setting this bit low enables the internal LIU front-end. Setting this pin high  
disables the LIU. Digital inputs RXA and RXB are sampled by the rising edge of E2.0i (Exclk)  
to strobe in the received line data. Digital transmit data is clocked out of pins TXA and TXB  
with the rising edge of C2.0o  
3
2
ELOS  
ELOS Enable. Set this bit low to set the analog loss of signal threshold to 40 dB below  
nominal. Set this bit high to set the analog loss of signal threshold to 20 dB below nominal.  
Tx8KEN  
Transmit 8 KHz Enable. If one, the pin RxMF/TxFP transmits a positive 8 KHz frame pulse  
synchronous with the serial data stream transmit on TXA/TXB. If zero, the pin RxMF/TxFP  
transmits a negative frame pulse synchronous with the multiframe boundary of data coming  
out of DSTo.  
1
0
ADSEQ  
- -  
Digital Milliwatt or Digital Test Sequence. If one, the A-law digital milliwatt analog test  
sequence will be selected by the Per Time Slot Control bits TTST and RTST.If zero, a PRBS  
generator / detector will be connected to channels with TTST, RRST respectively  
Reserved. Set this bit low for normal operation.  
Table 104 - Configuration Control Word  
(Page 2, Address 10H) (E1)  
Bit  
Name  
Functional Description  
7
WR  
Winding Ratio. Set this pin low if a 1:2.4 transformer is used on the transmit side. Set this  
pin high if a 1:2 transformer is used.  
6-4  
3
- -  
Reserved. Must be kept at 0 for normal operation.  
CPL  
Custom Pulse Level. Setting this bit low enables the internal ROM values in generating the  
transmit pulses. The ROM is coded for different line terminations or build out, as specified in  
the LIU Control word. Setting this pin high disables the pre-programmed pulse templates.  
Each of the 4 phases that generate a mark derive their D/A coefficients from the values  
programmed in the CPW registers.  
2 - 0  
TX2-0  
Transmit pulse amplitude. Select the TX2 –TX0 bits according to the line type, value of  
termination resistors (RT), and transformer turns ratio used  
TX2 TX1 TX0 Line Impedance(ohms) RT(ohms)  
Transformer Ratio  
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
120  
120  
0
1:2  
1:1  
1:2  
1:2  
1:2  
1:1  
1:2  
1:2  
0
120  
15  
12.1  
0
120/75  
75  
75  
0
75  
9.1  
12.1  
75/120  
After reset these bits are zero.  
Table 105 - LIU Tx Word  
(Page 2, Address 11H) (E1)  
104  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
6
- - -  
Unused.  
JFC  
Jitter Attenuator FIFO Centre. When this bit is toggled the read pointer on the jitter  
attenuator shall be centered. During this centering the jitter on the JA outputs is increased  
by 0.0625 U.I.  
5 - 3 JFD2-JFD0 Jitter Attenuator FIFO Depth Control Bits. These bits determine the depths of the jitter  
attenuator FIFO as shown below:  
JFD2  
JFD1  
JFD0  
Depth  
16  
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
32  
48  
64  
80  
96  
112  
128  
2
JACL  
- - -  
Jitter Attenuator FIFO Clear Bit. If one, the Jitter Attenuator, its FIFO and status are reset.  
The status registers will identify the FIFO as being empty. However, the actual bit values of  
the data in the JA FIFO will not be reset.  
1 - 0  
Unused.  
Table 106 - Jitter Attenuation Control Word  
(Page 2, Address 13H) (E1)  
Bit  
Name  
Functional Description  
7-0  
EHT7-0  
Equalizer High Threshold. These bits set the highest possible binary count tolerable  
coming out of the equalized signal peak detector before a lower level of equalization is  
selected. This register is only used when A/D based automatic equalization is selected using  
the Rx LIU Control Word. The recommended value to program is 10111011.  
Table 107 - Equalizer High Threshold  
(Page 2, Address 16H) (E1)  
Bit  
Name  
Functional Description  
7-0  
ELT7-0  
Equalizer Low Threshold. These bits set the lowest possible binary count tolerable coming  
out of the equalized signal peak detector before a higher level of equalization is selected.  
This register is only used when A/D based automatic equalization is selected using the Rx  
LIU Control Word. The recommended value to program is 00110000.  
Table 108 - Equalizer Low Threshold  
(Page 2, Address 17H) (E1)  
105  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
Reserved. Must be kept at 0 for normal operation.  
7 - 6  
5
- -  
IMA  
Inverse Mux Mode. Setting this bit high the I/O ports to allow for easy connection to the  
Mitel MT90220. DSTi becomes a serial 2.048 data stream. C4b becomes a 2.048 MHz clock  
that clocks DSTi in on the falling edge. RXFP becomes a positive framing pulse that is high  
for the first bit of the serial E1 stream coming from the pin DSTo. The data from DSTo is  
clocked out on the rising edge of Exclk. Set this pin low for all other applications.  
4 - 3  
2
- -  
Reserved. Must be kept at 0 for normal operation.  
8Men  
8Mb/s Bit Rate Select. Setting this bit low enables a serial bit rate on DSTi, CSTi and  
DSTo,CSTo of 2.048 Mb/s. Setting this bit high enables a gapped serial bit rate of 8.192 Mb/  
s on DSTi, CSTi, DSTo and CSTo.  
1 - 0 8MTS1- 0 8 Mb/s Time Slot Select. These two bits select the active timeslots on the serial 8.192 Mb/s  
channels. During the active timeslots incoming serial data on DSTi and CSTi is clocked into  
the device, and data is clocked out onto DSTo and CSTo. During inactive timeslots DSTo  
and CSTo are tristate. For all selections every fourth 8 Mb/s timeslot is active.  
The timeslot selection is as follows:  
8MTS1 8MST0  
Active timeslots  
0
0
1
1
0
1
0
1
0,4,8,12,16,20,24,28,32,36,40,44,48,52,56,60,64,68,72,76,80,84,88,92  
96,100,104,108,112,116,120,124  
1,5,9,13,17,21,25,29,33,37,41,45,49,53,57,61,65,69,73,77,81,85,89,93  
97,101,105,109,113,117,121,125  
2 ,6,10,14,18,22,26,30,34,38,42,46,50,54,58,62,66,70,74,78,82,86,  
90, 94, 98,102,106,110,114,118,122,126  
3,7,11,15,19,23,27,31,35,39,43,47,51,55,59,63,67,71,75,79,83,87,91,95  
99,103,107,111,115,119,123,127  
Table 109 - Serial Bit Rate  
(Page 2, Address 18H) (E1)  
Bit  
Name  
Functional Description  
7
En  
Enable. Set high to attach the HDLC0 controller to the channel specified below. Set  
low to disconnect the HDLC0.  
6
SaSEL  
Sa Bits Select. Set this bit to 0 to attach HDLC0 to the Sa bits. Set this bit to 1 to  
attach HDLC0 to a payload timeslot.  
5
- -  
Reserved. Must be kept at 0 for normal operation.  
4-0  
CH4-0  
Channel 4-0. This 5 bit number specifies the channel time HDLC0 will be attached  
to if enabled. Channel 0 is the first channel in the frame. Channel 31 is the last  
channel in an E1 frame. If enabled in a channel, HDLC data will be substituted for  
data from DSTi on the transmit side. Receive data is extracted from the incoming  
line data before the elastic buffer.  
Table 110 - HDLC0 Select  
(Page 2, Address 19H) (E1)  
106  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
En  
Enable. Set high to attach the HDLC1 controller to the channel specified below. Set  
low to disconnect the HDLC1.  
6-5  
4-0  
- -  
Reserved. Must be kept at 0 for normal operation.  
CH4-0  
Channel 4-0. This 5 bit number specifies the channel time HDLC1 will be attached  
to if enabled. Channel 0 is the first channel in the frame. Channel 31 is the last  
channel in an E1 frame. If enabled in a channel, HDLC data will be substituted for  
data from DSTi on the transmit side. Receive data is extracted from the incoming  
line data before the elastic buffer. Channel 0 selection is unavailable to this  
controller.  
Table 111 - HDLC1 Select  
(Page 2, Address 1AH) (E1)  
Bit  
Name  
Functional Description  
7
En  
Enable. Set high to attach the HDLC2 controller to the channel specified below. Set low to  
disconnect the HDLC2.  
6-5  
4-0  
- -  
Reserved. Must be kept at 0 for normal operation.  
CH4-0  
Channel 4-0. This 5 bit number specifies the channel time HDLC2 will be attached to if  
enabled. Channel 0 is the first channel in the frame. Channel 31 is the last channel in an E1  
frame. If enabled in a channel, HDLC data will be substituted for data from DSTi on the  
transmit side. Receive data is extracted from the incoming line data before the elastic buffer.  
Channel 0 selection is unavailable to this controller.  
Table 112 - HDLC2 Select  
(Page 2, Address 1BH) (E1)  
Bit  
Name  
Functional Description  
7
- -  
Reserved. Must be kept at 0 for normal operation.  
6-0  
CP6-0  
Custom Pulse. These bits provide the capability for programming the magnitude setting for  
the TTIP/TRING line driver A/D converter during the first phase of a mark. The greater the  
binary number loaded into the register, the greater the amplitude driven out. This feature is  
enabled when the control bit 3 - CPL of the Custom Tx Pulse Enable Register - address 11H  
of Page 2 is set high  
Table 113 - Custom Pulse Word 1  
(Page 2, Address 1CH) (E1)  
Bit  
Name  
Functional Description  
7
- -  
Reserved. Must be kept at 0 for normal operation.  
6-0  
CP6-0  
Custom Pulse. These bits provide the capability for programming the magnitude setting for  
the TTIP/TRING line driver A/D converter during the second phase of a mark. The greater  
the binary number loaded into the register, the greater the amplitude driven out. This feature  
is enabled when the control bit 3 - CPL of the Custom Tx Pulse Enable Register - address  
11H of Page 2 is set high  
Table 114 - Custom Pulse Word 2  
(Page 2, Address 1DH) (E1)  
107  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
Reserved. Must be kept at 0 for normal operation.  
7
- -  
6-0  
CP6-0  
Custom Pulse. These bits provide the capability for programming the magnitude setting for  
the TTIP/TRING line driver A/D converter during the third phase of a mark. The greater the  
binary number loaded into the register, the greater the amplitude driven out. This feature is  
enabled when the control bit 3 - CPL of the Custom Tx Pulse Enable Register - address 11H  
of Page 2 is set high  
Table 115 - Custom Pulse Word 3  
(Page 2, Address 1EH) (E1)  
Bit  
Name  
Functional Description  
7
- -  
Reserved. Must be kept at 0 for normal operation.  
6-0  
CP6-0  
Custom Pulse. These bits provide the capability for programming the magnitude setting for  
the TTIP/TRING line driver A/D converter during the fourth phase of a mark. The greater the  
binary number loaded into the register, the greater the amplitude driven out. This feature is  
enabled when the control bit 3 - CPL of the Custom Tx Pulse Enable Register - address 11H  
of Page 2 is set high  
Table 116 - Custom Pulse Word 4  
(Page 2, Address 1FH) (E1)  
108  
Preliminary Information  
MT9076  
20.5 Master Status 1 (Page03H) (E1)  
Address  
(A4A3A2A1A0)  
Register  
Function  
12H (Table 119)  
13H (Table 120)  
Timer Status Word  
1SEC, 2SEC, 400T, 8T, CALN, KLVE, T1,T2  
Most Significant Phase Status Word  
RSLIP, RSLPD, RxFRM, AUXP, RxFT,  
RxSBD2-0  
14H (Table 121)  
15H (Table 122)  
16H (Table 123)  
17H (Table 124)  
18H (Table 125)  
19H (Table 126)  
1AH (Table 127)  
1BH (Table 128)  
Least Significant Phase Status Word  
Receive Frame Alignment Signal  
Receive Signal Status Word  
Jitter Attenuator Status Word  
Receive Non-frame Alignment Signal  
Receive Multiframe Alignment Signal  
Sa Bits Report Word  
RxTS4-0, RxBC2-0  
RIU0 &RFA2-8  
LLOS  
JACS, JACF, JAE, JAF4, JAFC, JAE4, JAF  
RIU1, RNFAB, RALM, &RNU4-8  
RMAI1-4, X1, Y, X2, & X3  
Sa5, Sa6nibble, C8Sa6, CSa6, RxSa3-0  
Alarm Status Word 2  
RAIS, AISS, AIS16S, LOSS, AUXPS, MFALMS,  
SLIPS  
1CH  
Reserved  
1DH (Table 129)  
1EH (Table 130)  
1FH (Table 131)  
Analog Peak Detector  
Equalized Signal Peak Detector  
Identification Register  
AP7-0  
ESP7-0  
Set to 01111000  
Table 117 - Master Status 1 (Page 3) (E1)  
109  
MT9076  
Preliminary Information  
20.6  
Bit  
Master Status 1 (Page03H) (E1)  
Name  
Functional Description  
7
6
5
4
3
2
SYNC  
Receive Basic Frame Alignment. SYNC indicates the basic frame alignment status (1 -  
loss; 0 - acquired).  
MFSYNC Receive Multiframe Alignment. MFSYNC indicates the multiframe alignment status (1 -  
loss; 0 -acquired).  
CRCSYN Receive CRC-4 Synchronization. CRCSYN indicates the CRC-4 multiframe alignment  
status (1 - loss; 0 - acquired).  
REB1  
REB2  
Receive E-Bit One Status. REB1 indicates the status of the received E1 bit of the last  
multiframe.  
Receive E-Bit Two Status. REB2 indicates the status of the received E2 bit of the last  
multiframe.  
CRCRF  
CRC-4 Reframe. A one indicates that the receive CRC-4 multiframe synchronization could  
not be found within the time out period of 8 msec. after detecting basic frame  
synchronization. This will force a reframe when the maintenance option is selected and  
automatic CRC-4 interworking is de-selected.  
1
0
RED  
RED Alarm. RED goes high when basic frame alignment has been lost for at least 100  
msec. This bit will be low when basic frame alignment is acquired (I.431).  
CRCIWK CRC-4 Interworking. CRCIWK indicates the CRC-4 interworking status (1 - CRC-to-CRC;  
0 - CRC-to-non-CRC).  
Table 118 - Synchronization Status Word  
(Page 3, Address 10H) (E1)  
110  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
CRCS1 Receive CRC Error Status One. If one, the evaluation of the last received submultiframe 1  
resulted in an error. If zero, the last submultiframe 1 was error free. Updated on a  
submultiframe 1 basis.  
6
5
CRCS2 Receive CRC Error Status Two. If one, the evaluation of the last received submultiframe 2  
resulted in an error. If zero, the last submultiframe 2 was error free. Updated on a  
submultiframe 2 basis.  
RFAIL  
Remote CRC-4 Multiframe Generator/Detector Failure. If one, then each of the previous  
five seconds have an E-bit error count of greater than 989, and for this same period the  
receive RAI bit was zero (no remote alarm), and for the same period the SYNC bit was equal  
to zero (basic frame alignment has been maintained). If zero, indicates normal operation.  
4
LOSS  
Loss of Signal Status. If one, indicates the presence of a loss of signal condition. If zero,  
indicates normal operation. A loss of signal condition occurs when excess consecutive bit  
periods are zero. The threshold for this condition is set by the control bit L32Z. If L32Z is set  
high the threshold is 32 successive zeros. If L32Z is set low the threshold is 192 successive  
zeros. A loss of signal condition terminates when an average ones density of at least 12.5%  
has been received over a period of 192 contiguous pulse positions starting with a pulse.  
3
2
AIS16S Alarm Indication Signal 16 Status. If one, indicates an all ones alarm is being received in  
channel 16. If zero, normal operation. Updated on a frame basis.  
AISS  
RAIS  
Alarm Indication Status Signal. If one, indicates that a valid AIS or all ones signal is being  
received. If zero, indicates that a valid AIS signal is not being received. The criteria for AIS  
detection is determined by the control bit ASEL.  
1
0
Remote Alarm Indication Status. If one, there is currently a remote alarm condition (i.e.,  
received A bit is one). If zero, normal operation. Updated on a non-frame alignment frame  
basis.  
RCRS  
RAI and Continuous CRC Error Status. If one, there is currently an RAI and continuous  
CRC error condition. If zero, normal operation. Updated on a multiframe basis.  
Table 119 - Alarm Status Word 1  
(Page 3, Address 11H) (continued) (E1)  
111  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
1SEC One Second Timer Status. This bit changes state once every 0.5 second and is  
synchronous with the 2SEC timer. This feature is not available when the device is operated in  
freerun mode.  
6
5
4
3
2SEC Two Second Timer Status. This bit changes state once every second and is synchronous  
with the 1SEC timer.This feature is not available when the device is operated in freerun mode.  
400T  
8T  
400 msec. Timer Status. This bit changes state when the 400 msec. CRC-4 multiframe  
alignment timer expires.  
8 msec. Timer Status. This bit changes state when the 8 msec. CRC-4 multiframe alignment  
timer expires.  
CALN CRC-4 Alignment. This bit changes state every millisecond. When CRC-4 multiframe  
alignment has been achieved state changes of this bit are synchronous with the receive CRC-  
4 synchronization signal.  
2
1
0
KLVE  
Keep Alive. This bit is high when the AIS status bit has been high for at least 100msec. This  
bit will be low when AIS goes low (I.431).  
T1  
Timer One. This bit will be high upon loss of terminal frame synchronization persisting for 100  
msec. This bit shall be low when T2 becomes high. Refer to I.431 Section 5.9.2.2.3.  
T2  
Timer Two. This bit will be high when the MT9076 acquires terminal frame synchronization  
persisting for 10 msec. This bit shall be low when non-normal operational frames are  
received. I.431 Section 5.9.2.2.3.  
Table 120 - Timer Status Word  
(Page 3, Address 12H) (E1)  
Bit  
Name  
Functional Description  
7
RSLIP  
Receive Slip. A change of state (i.e., 1-to-0 or 0-to-1) indicates that a receive controlled  
frame slip has occurred.  
6
RSLPD  
Receive Slip Direction. If one, indicates that the last received frame slip resulted in a  
repeated frame, i.e., system clock is faster than network clock. If zero, indicates that the  
last received frame slip resulted in a lost frame, i.e., system clock is slower than network  
clock. Updated on an RSLIP occurance basis.  
5
4
RXFRM  
AUXP  
Receive Frame Delay. The most significant bit of the Receive Slip Buffer Phase Status  
Word. If one, the delay through the receive elastic buffer is greater than one frame in  
length; if zero, the delay through the receive elastic buffer is less than one frame in length.  
Auxiliary Pattern. This bit will go high when a continuous 101010... bit stream (Auxiliary  
Pattern) is received on the PCM 30 link for a period of at least 512 bits. If zero, auxiliary  
pattern is not being received. This pattern will be decoded in the presence of a bit error  
rate of as much as 10-3.  
3
RxFT  
Receiver Frame Toggle. This bit toggles on the falling edge of RxTS4.  
2-0  
RxSBD2-0 Receive Sub Bit Delay. The three least significant bits of the Receive Slip Buffer Phase  
Status Word. They indicate the clock, half clock and one eight clock cycle depth of the  
phase status word sample point (bits 2, 1, o respectively).  
Table 121 - Most Significant Phase Status Word  
(Page 3, Address 13H) (E1)  
112  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7 - 3 RxTS4 - 0 Receive Time Slot. A five bit counter that indicates the number of time slots between  
the receive elastic buffer internal write frame boundary and the ST-BUS read frame  
boundary. The count is updated every 250 uS.  
2 - 0 RxBC2 - 0 Receive Bit Count. A three bit counter that indicates the number of STBUS bit times  
there are between the receive elastic buffer internal write frame boundary and the ST-  
BUS read frame boundary. The count is updated every 250 uS.  
Table 122 - Least Significant Phase Status Word  
(Page 3, Address 14H) (E1)  
Bit  
Name  
Functional Description  
7
RIU0  
Receive International Use Zero. This is the bit which is received on the PCM 30 2048 kbit/  
sec. link in bit position one of the frame alignment signal. It is used for the CRC-4 remainder  
or for international use.  
6 - 0  
RFA2-8 Receive Frame Alignment Signal Bits 2 to 8. These bit are received on the PCM 30 2048  
kbit/sec. link in bit positions two to eight of frame alignment signal. These bits form the frame  
alignment signal and should be 0011011.  
Table 123 - Receive Frame Alignment Signal  
(Page 3, Address 15H) (E1)  
Bit  
Name  
Functional Description  
7
LLOSS LIU Loss of Signal indication. This bit will be high if the received signal is below the  
threshold selected by ELOS (page 2, address 10H) for a period of at least 1 msec. This bit  
will be low for normal operation.  
6-0  
- - -  
Unused  
Table 124 - Receive Signal Status Word  
(Page 3, Address 16H) (E1)  
113  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
JACS  
JACF  
Jitter Attenuated Clock Slow. If one it indicates that the dejittered clock period is increased  
by 1/16 UI. If zero the clock is at normal speed.  
6
Jitter Attenuated Clock Fast. If one it indicates that the dejittered clock period is decreased  
by 1/16 UI. If zero the clock is at normal speed.  
5
4
JAE  
Jitter Attenuator FIFO Empty. If one it indicates that the JA FIFO is empty.  
JAF4  
Jitter Attenuator FIFO with 4 Full Locations. If one it indicates that the JA FIFO has at  
least 4 full locations.  
3
2
JAFC  
JAE4  
Jitter Attenuator Center Full. If one it indicates that the JA FIFO is at least half full.  
Jitter Attenuator FIFO with 4 Empty Locations. If one it indicates that the JA FIFO has at  
most 4 empty locations.  
1
0
JAF  
- - -  
Jitter Attenuator FIFO Full. If one it indicates that the JA FIFO is full.  
Unused.  
Table 125 - Jitter Attenuator Status Word  
(Page 3, Address 17H) (E1)  
Bit  
Name  
Functional Description  
7
RIU1  
Receive International Use 1. This bit is received on the PCM 30 2048 kbit/sec. link in bit  
position one of the non-frame alignment signal. It is used for CRC-4 multiframe alignment or  
international use.  
6
5
RNFAB Receive Non-frame Alignment Bit. This bit is received on the PCM 30 2048 kbit/sec. link in  
bit position two of the non-frame alignment signal. This bit should be one in order to  
differentiate between frame alignment frames and non-frame alignment frames.  
RALM  
Receive Alarm. This bit is received on the PCM 30 2048 kbit/sec. link in bit position three  
(the A bit) of the non-frame alignment signal. It is used as a remote alarm indication (RAI)  
from the far end of the PCM 30 link (1 - alarm, 0 - normal).  
4-0  
RNU4-8 Receive National Use Four to Eight. These bits are received on the PCM 30 2048 kbit/sec.  
link in bit positions four to eight (the Sa bits) of the non-frame alignment signal.  
Table 126 - Receive Non-Frame Alignment Signal  
(Page 3, Address 18H) (E1)  
114  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7-4 RMAI1-4 Receive Multiframe Alignment Bits One to Four. These bits are received on the PCM  
30 2048 kbit/sec. link in bit positions one to four of time slot 16 of frame zero of every  
signaling multiframe. These bit should be 0000 for proper signaling multiframe alignment.  
3
X1  
Receive Spare Bit X1. This bit is received on the PCM 30 2048 kbit/sec. link in bit position  
five of time slot 16 of frame zero of every signaling multiframe.  
2
Y
Receive Y-bit. This bit is received on the PCM 30 2048 kbit/sec. link in bit position six of  
time slot 16 of frame zero of every signaling multiframe. The Y bit may indicate loss of  
multiframe alignment at the remote end (1 -loss of multiframe alignment; 0 - multiframe  
alignment acquired).  
1-0  
X2, X3 Receive Spare Bits X2 and X3. These bits are received on the PCM 30 2048 kbit/sec. link  
in bit positions seven and eight respectively, of time slot 16 of frame zero of every  
signaling multiframe.  
Table 127 - Receive Multiframe Alignment Signal  
(Page 3, Address 19H) (E1)  
Bit  
Name  
Functional Description  
7
Sa5  
Sa 5 Bit. The Sa5 bit is latched and reported here upon receipt of the eighth of  
consecutive instance of a new Sa6 nibble.  
6
5
CSa6nibble Changed Sa6 Nibble. This bit changes state upon detection of a change of state of  
incoming Sa6 nibbles.  
C8Sa6  
CSa6  
Changed Eight Sa6 Bit. This bit toggles upon receipt of the eighth of consecutive  
instance of a new Sa6 nibble.  
4
Changed Sa6 Bit. This bit toggles in the event of a change of state in the received Sa6  
bit.  
3 - 0  
RxSa 3-0 Receive Sa Nibble Three to Zero. This register contains the contents of the last Sa6  
nibble received. It is updated upon receipt of the eighth of consecutive instance of a  
new Sa6 nibble.  
Table 128 - Sa Bits Report Word  
(Page 3, Address 1AH) (E1)  
115  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
RAIS  
Remote Alarm Indication Status. If one, there is currently a remote alarm condition (i.e.,  
received A bit is one). If zero, normal operation. Updated on a non-frame alignment frame  
basis.  
6
AISS  
Alarm Indication Status Signal. If one, indicates that a valid AIS or all ones signal is  
being received. If zero, indicates that a valid AIS signal is not being received. The criteria  
for AIS detection is determined by the control bit ASEL.  
5
4
AIS16S Alarm Indication Signal 16 Status. If one, indicates an all ones alarm is being received in  
channel 16. If zero, normal operation. Updated on a frame basis.  
LOSS  
Loss of Signal Status. If one, indicates the presence of a loss of signal condition. If zero,  
indicates normal operation. A loss of signal condition occurs when an excess consecutive  
bit periods are zero. The threshold for this condition is set by the control bit L32Z. If L32Z is  
set high the threshold is 32 successive zeros. If L32Z is set low the threshold is 192  
successive zeros. A loss of signal condition terminates when an average ones density of at  
least 12.5% has been received over a period of 192 contiguous pulse positions starting  
with a pulse.  
3
AUXPS Auxiliary Pattern Status. This bit goes on high when a continuous 101010... bit stream  
(Auxiliary Pattern) is received on the PCM 30 link for a period of at least 512 bits. If zero,  
auxiliary pattern is not being received. This pattern will be decoded in the presence of a bit  
error rate of as much as 10-3.  
2
1
0
MFALMS Multiframe Alarm Status. This bit goes high in the event of receipt of a multiframe alarm.  
It goes low when the received multiframe alarm bit goes low.  
RSLIPS Receive Slip Status. A change of state (i.e., 1-to-0 or 0-to-1) indicates that a receive  
controlled frame slip has occurred.  
- - -  
Unused.  
Table 129 - Alarm Status Word 2  
(Page 3, Address 1BH) (E1)  
Bit  
Name  
Functional Description  
7 - 0  
AP4-0  
Analog Peak Detector. This status register gives the output value of a 5 bit A/D converter  
connected to a peak detector on RTIP/RRING.  
Table 130 - Analog Peak Detector  
(Page 3, Address 1DH) (E1)  
Bit  
Name  
Functional Description  
7 - 0  
ESP7-0  
Analog Peak. This status register gives the output value of an 8 bit A/D  
converter connected to a peak detector on RTIP/RRING.  
Table 131 - Equalized Signal Peak Detect  
(Page 3, Address 1EH) (E1)  
Bit  
Name  
Functional Description  
7-0  
ID7-0  
ID Number. Contains device code 01111000  
Table 132 - Identification Word  
(Page 3, Address 1FH) (E1)  
116  
Preliminary Information  
MT9076  
21.0 Master Status 2 (Page-4)  
21.1  
Master Status 2 (Page 04H) (E1)  
Address  
Register  
Function  
(A4A3A2A1A0)  
10H (Table 134) PRBS Error Counter  
11H (Table 135) CRC Multiframe counter for PRBS  
12H (Table 136) Alarm Reporting Latch  
13H (Table 137) Framing Bit Counter  
14H (Table 138) E-bit Error Counter Ebt  
15H (Table 139) E-bit Error Counter Ebt  
PS7-0  
PSM7-0  
RAI, AIS, AIS16, LOS, AUXP, MFALM, RSLIP  
EFAS7-0  
EC15-EC8  
EC7-EC0  
16H (Table 140) Most Significant Line Code Violation Error LCV15 - LCV8  
Counter  
17H (Table 141) Least Significant Line Code Violation Error LCV7 - LCV0  
Counter  
18H (Table 142) CRC- 4 Error Counter CEt  
19H (Table 143) CRC- 4 Error Counter CEt  
1AH  
CC15-CC8  
CC7 - CC0  
Unused.  
1BH (Table 144) Interrupt Word Zero  
TFSYNI, MFSYNI, CRCSYNI,AISI, LOSI,  
CEFI,YI, RxSLPI  
1CH (Table 145) Interrupt Word One  
1DH (Table 146) Interrupt Word Two  
1EH (Table 147) Interrupt Word Three  
1FH (Table 148) Overflow Reporting Latch  
FERRI, CRCERRI, EBITI, AIS16I, LCVI,  
PRBSERRI, AUXPI, RAII,  
FERRO,CRCO,FEBEO,LCVO,PRBSO,PRBSM  
FO, SaI  
HDLC0I,HDLC1I,HDLC2,JAI,1SECI,5SECI,RC  
RI,SIGI  
FERROL,CRCOL,FEBEOL,LCVOL, PRBSOL,  
PRBSMFOL  
Table 133 - Master Status 2 (Page 4) (E1)  
Bit  
Name  
Functional Description  
7 - 0  
PS7-0  
This counter is incremented for each PRBS error detected on any of the receive channels  
connected to the PRBS error detector.  
Table 134 - PRBS Error Counter  
(Page 4, Address 10H) (E1)  
Bit  
Name  
Functional Description  
7 - 0  
PSM7-0 This counter is incremented for each received CRC multiframe. It is cleared when the  
PRBS Error Counter is written to.  
Table 135 - CRC Multiframe Counter for PRBS  
(Page 4, Address 11H) (E1)  
117  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
RAI  
AIS  
Remote Alarm Indication. This bit is set to one in the event of receipt of a remote alarm,  
i.e. A(RAI) = 1. It is cleared when the register is read.  
6
5
4
3
2
1
0
Alarm Indication Signal. This bit is set to one in the event of receipt of an all ones alarm.  
It is cleared when the register is read.  
AIS16  
LOS  
AIS Time Slot 16 Alarm. This bit is set to one in the event of receipt of an all ones alarm  
in the time slot 16. It is cleared when the register is read.  
Loss of Signal. This bit is set to one in the event of loss of received signal. It is cleared  
when the register is read.  
AUXP  
Auxiliary Alarm. This bit is set to one in the event of receipt of the auxiliary alarm pattern.  
It is cleared when the register is read.  
MFALM Multiframe Alarm. This bit is set to one in the event of receipt of a multiframe alarm. It is  
cleared when the register is read.  
RSLIP  
- - -  
Received Slip. This bit is set to one in the event of receive elastic buffer slip. It is cleared  
when the register is read.  
Unused.  
Table 136 - Alarm Reporting Latch  
(Page 4, Address 12H) (E1)  
Bit  
Name  
Functional Description  
7 - 0  
EFAS7 - 0 Errored FAS Counter. An 8 bit counter that is incremented once for every receive  
frame alignment signal that contains one or more errors.  
Table 137 - Errored Frame Alignment Signal Counter  
(Page 4, Address 13H) (E1)  
Bit  
Name  
Functional Description  
1-0  
EC15-8  
E bit Error Counter. The most significant bits of the E bit error counter.  
Table 138 - E-bit Error Counter  
(Page 4, Address 14H) (E1)  
Bit  
Name  
Functional Description  
7 - 0  
EC7-0  
E bit Error Counter. The least significant 8 bits of the E-bit error counter.  
Table 139 - E-bit Error Counter  
(Page 4, Address 15H) (E1)  
Bit  
Name  
Functional Description  
7 - 0 LCV15 - 8 Most Significant Bits of the LCV Counter. The most significant eight bits of a 16 bit  
counter that is incremented once for every line code violation received. A line code is  
defined as a bipolar violation that is not a part of HDB3 encoding where the control bit  
EXZ is set low. Where EXZ is set high a violation is defined as either a non-HDB3 bipolar  
violation or an occurrance of excess zeros.  
Table 140 - Most Significant Bits of the LCV Counter  
(Page 4, Address 16H) (E1)  
118  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7 - 0  
LCV7 - 0 Least Significant Bits of the LCV Counter. The least significant eight bits of a 16 bit  
counter that is incremented once for every line code violation received. A line code is  
defined as a bipolar violation that is not a part of HDB3 encoding where the control bit EXZ  
is set low. Where EXZ is set high a violation is defined as either a non-HDB3 bipolar  
violation or an occurrance of excess zeros.  
Table 141 - Least Significant Bits of the LCV Counter  
(Page 4, Address 17H) (E1)  
Bit  
Name  
Functional Description  
7-0  
CC15 - 8 CRC-4 Error Counter These are the most significant eight bits of the CRC-6 error counter.  
Table 142 - CRC-4 Error Counter CEt  
(Page 4, Address 18H) (E1)  
Bit  
Name  
Functional Description  
7 - 0  
CC7 - 0 CRC-6 Error Counter. These are the least significant eight bits of the CRC-4 error counter.  
Table 143 - CRC-6Error Counter CEt  
(Page 4, Address 19H) (E1)  
119  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
TFSYNI Terminal Frame Synchronization Interrupt. When unmasked this interrupt bit goes high  
whenever a change of state of terminal frame synchronization condition exists. Reading this  
register clears this bit.  
6
5
MFSYNI Multiframe Synchronization Interrupt. When unmasked this interrupt bit goes high  
whenever a change of state of multiframe synchronization condition exists. Reading this  
register clears this bit.  
CRCSYNI CRC-4 Synchronization Interrupt. When unmasked this interrupt bit goes high whenever  
change of state of CRC-4 synchronization condition exists. Reading this register clears this  
bit.  
4
3
AISI  
Alarm Indication Signal Interrupt. When unmasked this interrupt bit goes high whenever a  
change of state of received all ones condition exists. Reading this register clears this bit.  
LOSI  
Loss of Signal Interrupt. When unmasked this interrupt bit goes high whenever a loss of  
signal (either analog - received signal 20 or 40 dB below nominal or digital - excess  
consecutive 0’s received) condition exists.  
2
CEFI  
YI  
Consecutively Errored Frame Alignment Interrupt. When unmasked this interrupt bit  
goes high whenever the last two frame alignment signals have errors. Reading this register  
clears this bit.  
1
0
Receive Y-bit Interrupt. When unmasked this interrupt goes high whenever loss of  
multiframe alignment occurs. Reading this register clears this bit.  
RxSLPI Receive SLIP Interrupt. When unmasked this interrupt bit goes high whenever a controlled  
frame slip occurs in the receive elastic buffer. Reading this register clears this bit.  
Table 144 - Interrupt Word Zero  
(Page 4, Address 1BH) (E1)  
120  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
FERRI  
Errored Framing Alignment Signal Interrupt. When unmasked this interrupt bit goes  
high whenever an erroneous bit in frame alignment signal is detected (provided the  
circuit is in terminal frame sync). Reading this register clears this bit.  
6
5
4
3
CRCERRI CRC-4 Error Interrupt. When unmasked this interrupt bit goes high whenever a local  
CRC-4 error occurs. Reading this register clears this bit.  
EBITI  
AIS16I  
LCVI  
Receive E-bit Error Interrupt. When unmasked this interrupt bit goes high upon  
detection of a wrong E-bit in multiframe. Reading this register clears this bit.  
Alarm Indication Signal Interrupt. When unmasked this interrupt bit goes high  
whenever all ones in time slot 16 occur.Reading this register clears this bit.  
Bipolar Violation Interrupt. When unmasked this interrupt bit goes high whenever a  
line code violation (excluding HDB3 encoding) is encountered. Reading this register  
clears this bit.  
2
1
0
PRBSERRI Pseudo Random Bit Sequence Error Interrupt. When unmasked this interrupt bit  
goes high upon detection of an error with a channel selected for PRBS testing. Reading  
this register clears this bit.  
AUXPI  
Auxiliary Pattern Alarm Interrupt. When unmasked this interrupt bit goes high  
whenever a sequence of 512 bit consecutive 101010. occur. Reading this register  
clears this bit.  
RAII  
Remote alarm Indication Interrupt. When unmasked this interrupt bit goes high  
whenever the bit 3 of non-frame alignment signal is high. Reading this register clears  
this bit.  
Table 145 - Interrupt Word One  
(Page 4, Address 1CH) (E1)  
121  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
FERRO  
Errored Framing Alignment Signal Counter Overflow Interrupt. When unmasked this  
interrupt bit goes high whenever the errored frame alignment signal counter changes from  
FFH to 00H. Reading this register clears this bit.  
6
CRCO  
CRC Error Counter Overflow Interrupt. When unmasked this interrupt bit goes high  
whenever the CRC error counter changes from FFH to 00H. Reading this register clears  
this bit.  
5
4
- - -  
Unused  
FEBEO  
E-bit Counter Overflow Interrupt. When unmasked this interrupt bit goes high whenever  
the E-bit counter changes from FFH to 00H. Reading this register clears this bit.  
3
2
1
0
LCVO  
Line Code Violation Counter Overflow Interrupt. When unmasked this interrupt bit goes  
high whenever the line code violation counter changes from FFH to 00H. Reading this  
register clears this bit.  
PRBSO  
Pseudo Random Bit Sequence Error Counter Overflow Interrupt. When unmasked  
this interrupt bit goes high whenever the PRBS error counter changes from FFH to 00H.  
Reading this register clears this bit.  
PRBSMFO Pseudo Random Bit Sequence Multiframe Counter Counter Overflow Interrupt.  
When unmasked this interrupt bit goes high whenever the multiframe counter attached to  
the PRBS error counter overflows. FFH to 00H. 1 - unmasked, 0 - masked.  
SaI  
Sa Bit Interrupt. When unmasked this interrupt goes high whenever either a change of  
state of any of the received Sa bits Sa5, Sa6, Sa7 or Sa8 (SaBorNi = 1) or a change of  
state of any of the received Sa nibbles (SaBorNi = 0). The control bit SaBorNi is located in  
page 1 address 12H bit 4.  
Table 146 - Interrupt Word Two  
(Page 4, Address 1DH) (E1)  
122  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
HDLC0I HDLC0 Interrupt. Whenever an unmasked HDLC0 interrupt occurs, this bit goes high.  
Reading this register clears this bit.  
6
5
4
HDLC1I HDLC1 Interrupt. Whenever an unmasked HDLC1 interrupt occurs, this bit goes high.  
Reading this register clears this bit.  
HDLC2I HDLC2 Interrupt. Whenever an unmasked HDLC2 interrupt occurs, this bit goes high.  
Reading this register clears this bit.  
JAI  
Jitter Attenuator Error Interrupt. Whenever an unmasked JAI interrupt occurs.  
If jitter attenuator FIFO comes within four bytes of an overflow or underflow, this bit goes  
high. Reading this register clears this bit.  
3
1SECI  
One Second Status Interrupt. When unmasked this interrupt bit goes high whenever the  
1SEC status bit (page 3 address 12H bit 7) goes from low to high. Reading this register  
clears this bit.  
2
1
0
5SECI  
RCRI  
SIGI  
Five Second Status Interrupt. When unmasked this interrupt bit goes high whenever the 5  
SEC status bit goes from low to high. Reading this register clears this bit.  
RCRI Interrupt. Whenever an unmasked RCRI interrupt occurs. If remote alarm and CRC  
error occur this bit goes high. Reading this register clears this bit.  
signaling Interrupt. When unmasked this interrupt bit goes high whenever a change of  
state (optionally debounced - see DBEn in the Data Link, signaling Control Word) is  
detected in the signaling bits (AB or ABCD) pattern. Reading this register clears this bit.  
Table 147 - Interrupt Word Three  
(Page 4, Address 1EH) (E1)  
Bit  
Name  
FERROL  
Functional Description  
7
6
5
Errored Frame Alignment Signal Counter Overflow Latch. This bit is set when  
the errored frame alignment signal counter overflows. It is cleared after being read.  
CRCOL  
CRC Error Counter Overflow Latch. This bit is set when the crc error counter  
overflows. It is cleared after being read.  
FEBEOL  
E bit Counter Overflow Latch. This bit is set when E bit counter overflows. It is  
cleared after being read.  
4
3
- - -  
LCVOL  
Line Code Violation Counter Overflow Latch. This bit is set when the line code  
violation counter overflows. It is cleared after being read.  
2
1
PRBSOL  
Pseudo Random Bit Sequence Error Counter Overflow Latch. This bit is set  
when the PRBS error counter overflows. It is cleared after being read.  
PRBSMFOL  
Pseudo Random Bit Sequence Multiframe Counter Overflow Latch. This bit is  
set when the multiframe counter attached to the PRBS error counter overflows. It is  
cleared after being read  
0
- - -  
Unused.  
Table 148 - Overflow Reporting Latch  
(Page 4, Address 1FH) (E1)  
123  
MT9076  
Preliminary Information  
21.2  
Per Channel Transmit signaling (Pages 5 and 6) (E1)  
Page 05H, addresses 10000 to 11111, and page 06H addresses 10000 to 10111 contain the Transmit signaling  
Control Words for Channel Associated signaling (CAS) channels 2 to 16 and 18 to 32 respectively. Table 149  
illustrates the mapping between the addresses of these pages and the CAS channel numbers. Control of these  
bits for any one channel is through the processor or controller port when the Per Time Slot Control bit RPSIG  
bit is high. Table 150 describes bit allocation within each of these registers.  
Page 5-6 Address:  
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10 11 12 13 14 15  
Equivalent CAS  
channel  
10 11 12 13 14 15 16  
Page 6 Address:  
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15  
Equivalent CAS  
channel  
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32  
Table 149 - Page 5, 6 Address Mapping to CAS signaling Channels (E1)  
Bit  
Name  
Functional Description  
7 - 4  
3 - 0  
- - -  
Unused.  
A(n)  
B(n)  
C(n)  
D(n)  
Transmit signaling Bits for Channel n. These bits are transmitted on the PCM 30 2048  
kbit/sec. Link in bit positions one to four of time slot 16 in frame n (when  
n = 1 to 15), and are the A, B, C, D signaling bits associated with channel n.  
Table 150 - Transmit Channel Associated signaling (E1) (Pages 5,6)  
Serial per channel transmit signaling control through CSTI is selected when RPSIG bit is zero. Table 151  
describes the function of CSTI time slots 1 to 30. if MSN bit is high, CSTI time slots 17 to 31 are selected. if  
MSN bit is low, CSTI time slots 1 to 15 are selected.  
Bit  
Name  
Functional Description  
7 - 4  
A(n),  
B(n),  
C(n),  
D(n)  
Transmit signaling Bits for Channel n. These bits are transmitted on the PCM 30 2048  
kbit/sec. Link in bit positions one to four of time slot 16 in frame n (where  
n = 1 to 15), and are the A, B, C, D signaling bits associated with channel n.  
3 - 0  
A(n),  
B(n),  
C(n),  
D(n)  
Transmit signaling Bits for Channel n. These bits are transmitted on the PCM 30 2048  
kbit/sec. Link in bit positions one to four of time slot 16 in frame n (where  
n = 1 to 15), and are the A, B, C, D signaling bits associated with channel n.  
Table 151 - E1 / Transmit Channels Usage - CSTi  
NOTE: This table illustrates bit mapping on the serial input stream - it does not refer to an internal register.  
124  
Preliminary Information  
MT9076  
21.3  
Per Time Slot Control Words (Pages 7 and 8) (E1)  
The control functions described by Table 152 are repeated for each PCM-30 channel. Page 07H addresses  
10H to 1FH correspond to time slots 0 to 15, while page 08H addresses 10H to 1FH correspond to time slots  
16 to 31.Table 153 illustrates the mapping between the addresses of these pages and the CEPT channel  
numbers.  
Page 8H Address:  
0
0
0
1
1
1
2
2
2
3
3
3
4
4
4
5
5
5
6
6
6
7
7
7
8
8
8
9
9
9
10 11 12 13 14 15  
10 11 12 13 14 15  
10 11 12 13 14 15  
Equivalent PCM 30  
Timeslots  
Page 9H Address:  
Equivalent PCM 30  
Timeslots  
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31  
Bit  
Name  
Functional Description  
7
TXMSG Transmit Message Mode. if high, the data from the corresponding address location of Tx  
message mode buffer is transmitted in the corresponding PCM 30 time slot. If zero, the data  
on DSTI is transmitted on the corresponding PCM 30 time slot.  
6
5
ADI  
Alternate Digit Inversion. If one, the corresponding transmit time slot data on DSTI has  
every second bit inverted. If zero, this bit has no effect on channel data.  
RTSL  
Remote Time Slot Loopback. If one, the corresponding PCM 30 receive time slot is looped  
to the corresponding PCM 30 transmit timeslot. This received time slot will also be present  
on DSTO. If zero, the loopback is disabled.  
4
3
LTSL  
TTST  
Local Time Slot Loopback. If one, the corresponding transmit time slot is looped to the  
corresponding receive time slot. This transmit time slot will also be present on the transmit  
PCM 30 stream. If zero, this loopback is disabled.  
Transmit Test. If one, a test signal, either digital milliwatt (when control bit ADSEQ is one)  
15  
or PRBS (2 -1) (ADSEQ is zero), will be transmitted in the corresponding PCM 30 time  
slot. More than one time slot may be activated at once. If zero, the test signal will not be  
connected to the corresponding time slot.  
2
1
0
RTST  
RPSIG  
- - -  
Receive Test. If one, the corresponding DSTo time slot will be used for testing. If control bit  
ADSEQ is one, a digital milliwatt signal will be transmit onto the DSTo channel. If ADSEQ is  
15  
zero the receive channel will be connected to the PRBS detector (2 -1).  
Serial Signaling Enable. If one, the transmit CAS signaling will be controlled by  
programming Page 05H. If zero, the transmit CAS signaling will be controlled through the  
CSTI stream.  
Unused.  
Table 152 - Per Time Slot Control Words (Pages 7 and 8) (E1)  
125  
MT9076  
Preliminary Information  
21.4  
Per Channel Receive signaling (Pages 9 and 0AH) (E1)  
Page 09H, addresses 10001 to 11111, and page 1AH addresses 10001 to 11111 contain the Receive signaling  
Control Words for CAS channels 2 to 16 and 18 to 32. Table 154 illustrates the mapping between the  
addresses of these pages and the CAS channel numbers. Table 155 describes bit allocation within each of  
these registers.  
Page 9 Address:  
0
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
9
10 11 12 13 14 15  
10 11 12 13 14 15  
Equivalent PCM 30  
Timeslots  
Page A Address:  
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15  
Equivalent PCM 30  
Timeslots  
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31  
Table 153 - Page 9, A Address Mapping to CAS Channels (E1)  
Bit  
Name  
Functional Description  
7 - 4  
3 - 0  
- - -  
Unused  
A(n)  
B(n)  
C(n)  
D(n)  
Receive signaling Bits for Channel n. These bits are received on the PCM 30 2048 kbit/  
sec. Link in bit positions one to four of time slot 16 in frame n (where n = 1 to 30) and are the  
A, B, C, D signaling bits associated with channel n.  
Table 154 - Receive Channel Associated signaling (Pages 9 and A) (E1)  
Serial per channel receive signaling status bits appear on ST-BUS stream CSTo. Table 156 describes the bit  
allocation within each of the 30 active ST-BUS time slot of CSTo.  
Bit  
Name  
Functional Description  
7 - 4  
A(n),  
B(n),  
C(n),  
D(n)  
Transmit signaling Bits for Channel n. These bits are transmitted on the PCM 30 2048 kbit/  
sec. Link in bit positions one to four of time slot 16 in frame n (where  
n = 1 to 15), and are the A, B, C, D signaling bits associated with channel n.  
3 - 0  
A(n),  
B(n),  
C(n),  
D(n)  
Transmit signaling Bits for Channel n. These bits are transmitted on the PCM 30 2048 kbit/  
sec. Link in bit positions one to four of time slot 16 in frame n (where  
n = 1 to 15), and are the A, B, C, D signaling bits associated with channel n.  
Table 155 - Receive CAS Channels (CSTo) (E1)  
126  
Preliminary Information  
MT9076  
22.0 HDLC Control and Status (Page B for HDLC0, Page C for HDLC1 and Page D  
for HDLC2)  
Register  
Address  
Function  
Control (Write/Verify)  
Status (Read)  
10H(Table 157)  
11H(Table 158)  
Address Recognition 1  
Address Recognition 2  
TX FIFO  
- --  
- --  
ADR16-10,A1EN  
ADR26-20, A2EN  
BIT7-0  
12H (Table159/160)  
13H(Table 161)  
RX FIFO  
- --  
HDLC Control 1  
ADREC, RxEN, TxEN, EOP, FA, Mark-  
idle, TR, FRUN  
14H(Table 162)  
15H(Table 163)  
16H(Table 164)  
- --  
HDLC Status  
INTGEN, Idle-Chan, RQ9, RQ8,  
TxSTAT2, TxSTAT1, RxSTAT2, RxSTAT1  
HDLC Control 2  
Interrupt Mask  
- --  
- --  
INTSEL, CYCLE, TxCRCI, SEVEN,  
RxFRST, TxFRST  
GaIM, RxEOPIM, TxEOPIM, RxFEIM,  
TxFLIM, FA:TxUNDERIM, RxFFIM,  
RxOVFIM  
17H(Table 165)  
- --  
Interrupt Status (*)  
Ga, RxEOP, TxEOP, RxFE, TxFL,  
FA:TxUNDER, RxFF, RxOVF  
18H(Table 166)  
19H(Table 167)  
1AH(Table 168)  
1BH(Table 169)  
- --  
- --  
Rx CRC MSB  
Rx CRC LSB  
- --  
CRC15-CRC8  
CRC7-CRC0  
TxCNT7-0  
Low TX byte count  
Test Control  
- --  
HRST, RTLOOP, CRCTST, FTST,  
ARTST, HLOOP  
1CH(Table 170)  
1DH(Table 171)  
1EH(Table 172)  
1FH(Table 173)  
- --  
Test Status  
RxCLK, TxCLK, VCRC, VADDR  
RSV, RFD2-0,RSV, TFD2-0  
RSV, RFFS2-0, RSV, TFLS2-0  
TxCNT15-8  
HDLC Control 3  
HDLC Control 4  
- --  
- --  
- --  
Extended TX byte  
count  
Table 156 - HDLC0, HDLC1, HDLC2 Control and Status (Page B, C, D)  
127  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7 - 2  
ADR16-11 Address 16 - 11. A six bit address used for comparison with the first byte of the received  
address. ADR16 is MSB.  
1
0
ADR10  
A1EN  
Address 10. This bit is used in address comparison if a seven bit address is being  
checked for (control bit four of control register 2 is set).  
First Address Comparison Enable. When this bit is high, the above six (or seven) bit  
address is used in the comparison of the first address byte.  
If address recognition is enabled, any packet failing the address comparison will not be  
stored in the RX FIFO. A1EN must be high for All-call (1111111) address recognition for  
single byte address. When this bit is low, this bit mask is ignored in address comparison  
Table 157 - HDLC Address Recognition Register 1  
(Page B,C & D, Address 10H)  
Bit  
Name  
Functional Description  
7 - 1  
ADR26-20 Address 26 - 20. A seven bit address used for comparison with the second byte of the  
received address. ADR26 is MSB. This mask is ignored (as well as first byte mask) if all  
call address (1111111) is received.  
0
A2EN  
Second Address Comparison Enable. When this bit is set high, the above seven bit  
address is used in the comparison of the second address byte.  
If address recognition is enabled, any packet failing the address comparison will not be  
stored in the RX FIFO. A2EN must be high for All-call address recognition. When this bit is  
low, this bit mask is ignored in address comparison  
Table 158 - HDLC Address Recognition Register 2  
(Page B,C & D, Address 11H)  
Bit  
Name  
Functional Description  
7 - 0  
BIT7-0 This eight bit word is tagged with the two status bits from the control register 1 (EOP and FA),  
and the resulting 10 bit word is written to the TX FIFO. The FIFO status is not changed  
immediately after a write or read occurs. It is updated after the data has settled and the  
transfer to the last available position has finished.  
Table 159 - TX FIFO Write Register  
(Page B,C & D, Address 12H)  
128  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7 - 0  
BIT7-0 This is the received data byte read from the RX FIFO. The status bits of this byte can be read  
from the status register. The FIFO status is not changed immediately when a write or read  
occurs. It is updated after the data has settled and the transfer to the last available position has  
finished.  
Table 160 - RX FIFO Read Register  
(Page B,C & D, Address 12H)  
Bit  
Name  
Functional Description  
7
ADREC  
Address Recognition. When high this bit will enable address recognition. This forces the  
receiver to recognize only those packets having the unique address as programmed in the  
Receive Address Recognition Registers or if the address is an All call address.  
6
5
RxEN  
TxEN  
Receive Enable. When low this bit will disable the HDLC receiver. The receiver will disable  
after the rest of the packet presently being received is finished. The receiver internal clock  
is disabled.  
When high the receiver will be immediately enabled and will begin searching for flags, Go-  
aheads etc.  
Transmit Enable. When low this bit will disable the HDLC transmitter. The transmitter will  
disable after the completion of the packet presently being transmitted. The transmitter  
internal clock is disabled.  
When high the transmitter will be immediately enabled and will begin transmitting data, if  
any, or go to a mark idle or interframe time fill state.  
4
3
EOP  
FA  
End of Packet. Forms a tag on the next byte written the TX FIFO, and when set will  
indicate an end of packet byte to the transmitter, which will transmit an FCS following this  
byte. This facilitates loading of multiple packets into TX FIFO. Reset automatically after a  
write to the TX FIFO occurs.  
Frame Abort. Forms a tag on the next byte written to the TX FIFO, and when set will  
indicate to the transmitter that it should abort the packet in which that byte is being  
transmitted. Reset automatically after a write to the TX FIFO.  
2
1
Mark-Idle Mark - Idle. When low, the transmitter will be in an idle state. When high it is in an  
interframe time fill state. These two states will only occur when the TX FIFO is empty.  
TR  
Transparent Mode. When high this bit will enable transparent mode. This will perform the  
parallel to serial conversion without inserting or deleting zeros. No CRC bytes are sent or  
monitored nor are flags or aborts. A falling edge of TxEN for transmit and a falling edge of  
RxEN for receive is necessary to initialize transparent mode. This will also synchronize the  
data to the transmit and receive channel structure. Also, the transmitter must be enabled  
through control register 1 before transparent mode is entered.  
0
FRUN  
Freerun. When high the HDLC TX and RX are continuously enabled providing the RxEN  
and TxEN bits are set.  
Table 161 - HDLC Control Register 1  
(Page B,C & D, Address 13H)  
129  
MT9076  
Preliminary Information  
Bit  
Name  
INTGEN  
Functional Description  
7
Interrupt Generated. Set to 1 when an interrupt (in conjunction with the Interrupt Mask  
Register) has been generated by the HDLC. This is an asynchronous event. It is reset  
when the interrupt Register is read.  
6
Idle Chan Idle Channel. Set to a 1 when an idle Channel state (15 or more ones) has been detected  
at the receiver. This is an asynchronous event. On power reset, this may be 1 if the clock  
(RXC) was not operating. Status becomes valid after the first 15 bits or the first zero is  
received.  
5 - 4  
RQ9, RQ8 Byte Status bits from RX FIFO. These bits determine the status of the byte to be read  
from RX FIFO as follows:  
RQ9 RQ8 Byte Status  
0
0
1
1
0
1
0
1
Packet Byte  
First Byte  
Last byte of a good packet.  
Last byte of a bad packet.  
3 - 2  
TxSTAT2-1 These bits determine the status of the TX FIFO as follows:  
TxSTAT2 TxSTAT1 TX FIFO Status  
0
0
0
1
TX FIFO full up to the selected status level or more.  
The number of bytes in the TX FIFO has reached or  
exceeded the selected interrupt threshold level.  
TX FIFO empty.  
The number of bytes in the TX FIFO is less than the  
selected interrupt threshold level.  
1
1
0
1
1 - 0 RxSTAT2 - 1 These bits determine the status of the RX FIFO as follows:  
RxSTAT2 RxSTAT1 RX FIFO Status  
0
0
0
1
RX FIFO empty  
The number of bytes in the RX FIFO is less  
than the interrupt threshold level.  
RX FIFO full.  
The number of bytes in the RX FIFO has reached or  
exceeded the interrupt threshold level.  
1
1
0
1
Table 162 - HDLC Status Register  
(Page B,C & D Address 14H)  
130  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
INTSEL Interrupt Selection. When high, this bit will cause bit 2 of the Interrupt Register to reflect  
a TX FIFO underrun (TXunder). When low, this interrupt will reflect a frame abort (FA).  
6
5
CYCLE Cycle. When high, this bit will cause the transmit byte count to reload one minus the  
value initially loaded into the Transmit Byte Count Register.  
TxCRCI Transmit CRC Inhibited. When high, this bit will inhibit transmission of the CRC. That is,  
the transmitter will not insert the computed CRC onto the bit stream after seeing the EOP  
tag byte. This is used in V.120 terminal adaptation for synchronous protocol sensitive UI  
frames.  
4
SEVEN Seven Bit Address Recognition. When high, this bit will enable seven bits of address  
recognition in the first address byte. The received address byte must have bit 0 equal to 1  
which indicates a single address byte is being received.  
3
2
1
- -  
- -  
Reserved, must be zero for normal operation.  
Reserved, must be zero for normal operation.  
RxFRST RX FIFO Reset. When high, the RX FIFO will be reset. This causes the receiver to be  
disabled until the next reception of a flag. The status register will identify the FIFO as  
being empty. However, the actual bit values in the RX FIFO will not be reset.  
0
TxFRST TX FIFO Reset. When high, the TX FIFO will be reset. The Status Register will identify  
the FIFO as being empty. This bit will be reset when data is written to the TX FIFO.  
However, the actual bit values of data in the TX FIFO will not be reset. It is cleared by the  
next write to the TX FIFO.  
Table 163 - HDLC Control Register 2  
(Page B,C & D, Address 15H)  
Bit  
Name  
Functional Description  
7-0  
GaIM  
This register is used with the Interrupt Register to mask out the interrupts that are not  
required by the microprocessor. Interrupts that are masked out will not drive the pin  
IRQ low; however, they will set the appropriate bit in the Interrupt Register. An  
interrupt is disabled when the microprocessor writes a 0 to a bit in this register.  
RxEOPIM  
TxEOPIM  
RxFEIM  
TxFLIM  
This register is cleared on power reset.  
FA:TxUNDE  
RIMRxFFIM  
RxOVFIM  
Table 164 - HDLC Interrupt Mask Register  
(Page B,C & D, Address 16H)  
131  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
GA  
Go Ahead. Indicates a go-ahead pattern was detected by the HDLC receiver. This bit is  
reset after a read.  
6
RxEOP  
End Of Packet Detected. This bit is set when an end of packet (EOP) byte was written into  
the RX FIFO by the HDLC receiver. This can be in the form of a flag, an abort sequence or  
as an invalid packet. This bit is reset after a read.  
5
4
TxEOP  
RxFE  
Transmit End Of Packet. This bit is set when the transmitter has finished sending the  
closing flag of a packet or after a packet has been aborted. This bit is reset after read.  
End Of Packet Read. This bit is set when the byte about to be read from the RX FIFO is the  
last byte of the packet. It is also set if the Rx FIFO is read and there is no data in it. This bit  
is reset after a read.  
3
2
TXFL  
FA:  
TX FIFO Low. This bit is set when the Tx FIFO is emptied below the selected low threshold  
level. This bit is reset after a read.  
Frame Abort/TX FIFO Underrun.When Intsel bit of Control Register 2 is low, this bit (FA) is  
TxUNDER set when a frame abort is received during packet reception. It must be received after a  
minimum number of bits have been received (26) otherwise it is ignored.  
When INTSEL bit of Control Register 2 is high, this bit is set for a TX FIFO underrun  
indication. If high it Indicates that a read by the transmitter was attempted on an empty Tx  
FIFO.  
This bit is reset after a read.  
1
0
RXFF  
RX FIFO Full. This bit is set when the Rx FIFO is filled above the selected full threshold  
level. This bit is reset after a read.  
RxOVF  
RX FIFO Overflow. Indicates that the 128 byte RX FIFO overflowed (i.e. an attempt to write  
to a 128 byte full RX FIFO). The HDLC will always disable the receiver once the receive  
overflow has been detected. The receiver will be re-enabled upon detection of the next flag,  
but will overflow again unless the RX FIFO is read. This bit is reset after a read.  
Table 165 - HDLC Interrupt Status Register  
(Page B,C & D, Address 17H)  
Bit  
Name  
Functional Description  
7-0  
CRC15-8 The MSB byte of the CRC received from the transmitter. These bits are as the  
transmitter sent them; that is, most significant bit first and inverted. This register is updated  
at the end of each received packet and therefore should be read when end of packet is  
detected.  
Table 166 - Receive CRC MSB Register  
(Page B,C & D, Address 18H)  
Bit  
Name  
Functional Description  
7-0  
CRC7-0 The LSB byte of the CRC received from the transmitter. These bits are as the  
transmitter sent them; that is, most significant bit first and inverted. This register is  
updated at the end of each received packet and therefore should be read when end of  
packet is detected.  
Table 167 - Receive CRC LSB Register  
(Page B,C & D, Address 19H)  
132  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7-0  
TxCNT7-0  
Low Transmit Byte Count Register. This register, along with the Extended  
Transmit Byte Count Register indicates the length of the packet about to be  
transmitted. For a packet size of 255 or less it is only necessary to write this  
register. When this register reaches the count of one, the next write to the Tx FIFO  
will be tagged as an end of packet byte. The counter decrements at the end of the  
write to the Tx FIFO. If the Cycle bit of Control Register 2 is set high, the counter will  
cycle through the programmed value continuously.  
Table 168 - Low Transmit Byte Count Register  
(Page B,C & D, Address 1AH)  
Bit  
Name  
Functional Description  
7
HRST  
HDLC Reset. When this bit is set to one, the HDLC will be reset. This is similar to  
RESET being applied, the only difference being that this bit will not be reset. This bit  
can only be reset by writing a zero twice to this location or applying RESET.  
6
RTLOOP  
RT Loopback. When this bit is high, receive to transmit HDLC loopback will be  
activated. Receive data, including end of packet indication, but not including flags or  
CRC, will be written to the TX FIFO as well as the RX FIFO. When the transmitter is  
enabled, this data will be transmitted as though written by the microprocessor. Both  
good and bad packets will be looped back. Receive to transmit loopback may also  
be accomplished by reading the RX FIFO using the microprocessor and writing  
these bytes, with appropriate tags, into the TX FIFO.  
5
4
3
- -  
- -  
Reserved. Must be set to 0 for normal operation.  
Reserved. Must be set to 0 for normal operation.  
CRCTST  
CRC Remainder Test. This bit allows direct access to the CRC Comparison  
Register in the receiver through the serial interface. After testing is enabled, serial  
data is clocked in until the data aligns with the internal comparison (16 RXC clock  
cycles) and then the clock is stopped. The expected pattern is F0B8 hex. Each bit  
of the CRC can be corrupted to allow more efficient testing.  
2
FTST  
FIFO Test. This bit allows the writing to the RX FIFO and reading of the TX FIFO  
through the microprocessor to allow more efficient testing of the FIFO status/  
interrupt functionality. This is done by making a TX FIFO write become a RX FIFO  
write and a RX FIFO read become a TX FIFO read. In addition, EOP/FA and RQ8/  
RQ9 are re-defined to be accessible (i.e. RX write causes EOP/FA to go to RX fifo  
input; TX read looks at output of TX fifo through RQ8/RQ9 bits).  
1
0
ARTST  
HLOOP  
Address Recognition Test. This bit allows direct access to the Address  
Recognition Registers in the receiver through the serial interface to allow more  
efficient testing. After address testing is enabled, serial data is clocked in until the  
data aligns with the internal address comparison (16 RXc clock cycles) and then  
clock is stopped.  
TR Loopback. When high, transmit to receive HDLC loopback will be activated.  
The packetized transmit data will be looped back to the receive input. RXEN and  
TXEN bits must also be enabled.  
Table 169 - HDLC Test Control Register  
(Page B,C & D, Address 1BH)  
133  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7-4  
3
- -  
These bits are reserved.  
RxCLK  
Receive Clock. This bit represents the receiver clock generated after the RXEN  
control bit, but before zero deletion is considered.  
2
1
TxCLK  
VCRC  
Transmit Clock. This bit represents the transmit clock generated after the TXEN  
control bit, but before zero insertion is considered.  
Valid CRC. This is the CRC recognition status bit for the receiver. Data is clocked  
into the register and then this bit is monitored to see if comparison was successful  
(bit will be high).  
0
VADDR  
Valid Address. This is the address recognition status bit for the receiver. Data is  
clocked into the Address Recognition Register and then this bit is monitored to see  
if comparison was successful (bit will be high).  
Table 170 - HDLC Test Status Register  
(Page B,C & D, Address 1CH)  
134  
Preliminary Information  
MT9076  
Bit  
Name  
Functional Description  
7
- --  
Unused.  
These bits select the Rx FIFO full status level:  
6-4  
RFD2-0  
RFD2  
RFD1  
RFD0  
Full Status Level  
0
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
16  
32  
0
0
48  
0
64  
1
80  
1
96  
1
1
112  
128  
3
- --  
Unused.  
2-0  
TFD2-0  
These bits select the Tx HDLC FIFO full status level:  
TFD2  
TFD1  
TFD0  
Full Status Level  
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
16  
32  
48  
64  
80  
96  
112  
128  
Table 171 - HDLC Control Register 3  
(Page B, C & D, Address 1DH)  
135  
MT9076  
Preliminary Information  
Bit  
Name  
Functional Description  
7
- --  
Unused.  
These bits select the RXFF (Rx FIFO Full) interrupt threshold level:  
6-4  
RFFS2-0  
RFFS2  
RFFS1  
RFFS0  
RX FIFO Full Interrupt threshold Level.  
0
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
64  
72  
0
0
80  
0
88  
1
96  
1
104  
112  
120  
1
1
3
- --  
Unused.  
2-0  
TFLS2-0  
These bits select the TXFL (Tx FIFO Low) interrupt threshold level:  
TFLS2  
TFLS1  
TFLS0  
TX FIFO Low Interrupt threshold Level.  
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
8
16  
24  
32  
40  
48  
56  
64  
Table 172 - HDLC Control Register 4  
(Page B, C & D, Address 1EH)  
Bit  
Name  
Functional Description  
7-0  
TxCNT15-8 Extended Transmit Byte Count Register. This register, along with the Transmit Byte  
Count Register indicates the length of the packet about to be transmitted. Values  
programmed into this register are not internally updated until the next write to the Low  
Transmit Byte Count Register. When the internal counter decrements to one, the next  
write to the Tx FIFO will be tagged as an end of packet byte. The counter decrements at  
the end of the write to the Tx FIFO. If the Cycle bit of Control Register 2 is set high, the  
counter will cycle through the programmed value continuously.  
Table 173 - Extended Transmit Byte Count Register  
(Page B,C & D, Address 1FH)  
136  
Preliminary Information  
MT9076  
23.0 Transmit National Bit Buffer (Page 0EH)  
Page 0EH, address 10H to 14H contain the five bytes of the transmit national bit buffer (TNBB0 - TNBB4  
respectively). This feature is functional only when control bit NBTB (page 01H, address 17H) is one.  
Bit  
Name  
Functional Description  
7 - 0  
TNBBn.F1 Transmit S  
Bits Frames 1 to 15. This byte contains the bits transmitted in bit position  
an+4  
-
n+4 of channel zero of frames 1, 3, 5, 7, 9, 11, 13 and 15 when CRC-4 multiframe  
TNBBn.F15 alignment is used, or of consecutive odd frames when CRC-4 multiframe alignment is not  
used. n = 0 to 4 inclusive and corresponds to a byte of the receive national bit buffer.  
Table 174 - Transmit National Bit Buffer Bytes Zero to Four (Page 0EH)  
24.0 Receive National Bit Buffer (Page 0FH)  
Page 0FH, addresses 10H to 14H contain the five bytes of the receive national bit buffer (RNBB0 - RNBB4  
respectively).  
Bit  
Name  
Functional Description  
7 - 0 RNBBn.F1 Receive S  
Bits Frames 1 to 15. This byte contains the bits received in bit position  
an+4  
n+4 of channel zero of frames 1, 3, 5, 7, 9, 11, 13 and 15 when CRC-4 multiframe  
alignment is used, or of consecutive odd frames when CRC-4 multiframe alignment is  
not used. n = 0 to 4 inclusive and corresponds to a byte of the receive national bit  
buffer.  
-
RNBBn.F15  
Table 175 - Receive National Bit Buffer Bytes Zero to Four (Page 0FH)  
137  
MT9076  
Preliminary Information  
25.0 AC/DC Electrical Characteristics  
Absolute Maximum Ratings* - Voltages are with respect to ground (V ) unless otherwise stated.  
SS  
Parameter  
Symbol  
Min  
Max  
Units  
1
2
3
4
5
6
Supply Voltage  
V
-0.3  
-0.3  
7
V
V
DD  
Voltage at Digital Inputs  
Current at Digital Inputs  
Voltage at Digital Outputs  
Current at Digital Outputs  
Storage Temperature  
V
V
V
+ 0.3  
DD  
I
I
30  
+ 0.3  
mA  
V
I
V
-0.3  
-65  
O
DD  
I
30  
mA  
˚C  
O
T
150  
ST  
* Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied.  
Recommended Operating Conditions - Voltages are with respect to ground (V ) unless otherwise stated.  
SS  
Characteristics  
Sym  
Min  
Typ  
Max  
Units  
Test Conditions  
1
2
Operating Temperature  
Supply Voltage  
T
-40  
3.0  
85  
˚C  
V
OP  
V
3.3  
3.6  
DD  
Typical figures are at 25˚C and are for design aid only: not guaranteed and not subject to production testing.  
DC Electrical Characteristics - Voltages are with respect to ground (V ) unless otherwise stated.  
SS  
Characteristics  
Supply Current  
Sym  
Min  
Typ  
Max  
Units  
Test Conditions  
1
I
98  
mA  
Outputs unloaded.  
Transmitting an all  
1’s signal.  
DD  
2
3
4
5
6
7
Input High Voltage (Digital Inputs)  
Input Low Voltage (Digital Inputs)  
Input Leakage (Digital Inputs)  
V
2.0  
0
V
V
V
IH  
DD  
V
0.8  
12*  
IL  
I
1
1
µA  
V
V = 0 to V  
I DD  
IL  
Output High Voltage (Digital Outputs)  
Output Low Voltage (Digital Outputs)  
High Impedance Leakage (Digital I/O)  
V
0.7V  
V
DD  
OH  
dd  
V
V
0.3V  
12  
V
OL  
OZ  
SS  
dd  
I
µA  
V = 0 to V  
O DD  
Characteristics are for clocked operation over the ranges of recommended operating temperature and supply voltage.  
Typical figures are at 25˚C and are for design aid only: not guaranteed and not subject to production testing.  
30 µA for inputs of boundary scan test port: Osc1,Tdi, Tms, Tclk and Trst.  
138  
Preliminary Information  
MT9076  
AC Electrical Characteristics - Motorola Microprocessor Timing  
Characteristics  
Sym Min Typ  
Max  
Units  
Test Conditions  
1
2
3
4
5
6
7
8
9
DS low  
t
70  
60  
0
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
DSL  
DS High  
CS Setup  
t
DSH  
t
CSS  
R/W Setup  
t
1
RWS  
Address Setup  
CS Hold  
t
4
ADS  
CSH  
RWH  
t
0
R/W Hold  
t
7
Address Hold  
Data Delay Read  
t
4
ADH  
DDR  
DHR  
t
75  
75  
75  
CL=150pF  
CL=150pF  
10 Data Hold Read  
11 Data A  
t
t
DAZ  
DSW  
DHW  
12 Data Setup Write  
13 Data Hold Write  
t
7
9
t
Characteristics are for clocked operation over the ranges of recommended operating temperature and supply voltage.  
Typical figures are at 25˚C and are for design aid only: not guaranteed and not subject to production testing.  
t
CYC  
t
DSL  
V
V
V
DS  
CS  
TT  
TT  
TT  
t
DSH  
t
t
t
CSS  
CSH  
t
RWH  
RWS  
R/W  
t
t
ADS  
ADH  
V
V
A0-A4  
TT  
t
DDR  
t
DAZ  
VALID DATA  
D0-D7  
READ  
V
TT, CT  
t
t
t
DHR  
DHW  
DSW  
D0-D7  
WRITE  
VALID DATA  
V
TT  
Note: DS and CS may be connected together.  
Figure 16 - Motorola Microport Timing  
139  
MT9076  
Preliminary Information  
AC Electrical Characteristics - Intel Microprocessor Timing  
Characteristics  
Sym Min Typ  
Max  
Units  
Test Conditions  
1
2
3
4
5
6
7
8
9
RD low  
t
70  
60  
0
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
RDL  
RD High  
CS Setup  
CS Hold  
t
RDH  
t
CSS  
t
0
CSH  
Address Setup  
t
4
ADS  
ADH  
DDR  
Address Hold  
t
4
Data Delay Read  
Data Active to High Z Delay  
Data Setup Write  
t
75  
75  
CL=150pF  
t
DAZ  
DSW  
DHW  
t
7
9
10 Data Hold Write  
t
Typical figures are at 25˚C and are for design aid only: not guaranteed and not subject to production testing.  
t
CYC  
t
RDL  
RD  
CS  
V
V
V
TT  
TT  
TT  
t
RDH  
t
t
t
CSS  
CSH  
CSH  
WR  
t
t
ADH  
t
ADS  
ADH  
A0-A4  
V
V
TT  
t
DDR  
t
DAZ  
VALID DATA  
D0-D7  
READ  
V
TT, CT  
t
t
DSW  
DHW  
D0-D7  
WRITE  
VALID DATA  
V
TT  
Figure 17 - Intel Microport Timing  
140  
Preliminary Information  
MT9076  
AC Electrical Characteristics - Transmit Data Link Timing (T1 mode)  
Characteristic  
Sym  
Min  
Typ  
Max Units  
Test Conditions  
1
2
3
Data Link Clock Pulse Width  
Data Link Setup  
tDW  
tTDS  
tTDH  
324  
ns 150pF  
35  
35  
ns  
ns  
Data Link Hold  
t
DW  
V
V
TT, CT  
TxDLCLK  
TxDL  
t
DLH  
t
DLS  
V
TT  
Figure 18 - Transmit Data Link Timing Diagram (T1 mode)  
AC Electrical Characteristics - Transmit Data Link Timing (E1 mode)  
Characteristic  
Sym  
Min  
Typ  
Max Units  
Test Conditions  
1
2
3
Data Link Clock Output Delay  
Data Link Setup  
tTDC  
tTDS  
tTDH  
72  
35  
35  
ns 150pF  
ns  
ns  
Data Link Hold  
C4b  
V
TT  
t
TDC  
V
V
TT, CT  
TxDLCLK  
TxDL  
t
DLH  
t
DLS  
V
TT  
Figure 19 - Transmit Data Link Timing Diagram (E1 mode)  
F0b  
TIME SLOT 0  
Bits 4,3,2,1,0  
Example A - 20 kb/s  
TxDLCLK  
TxDL  
Example B - 12 kb/s  
TxDLCLK  
TxDL  
Figure 20 - Transmit Data Link Functional Timing (E1 mode)  
141  
MT9076  
Preliminary Information  
AC Electrical Characteristics - Receive Data Link Timing (T1 mode)  
Characteristic  
Sym  
Min  
Typ  
Max Units  
Test Conditions  
50pF  
1
2
3
Data Link Clock Output Delay  
Data Link Output Delay  
RxFP Output Delay  
tRDC  
tRDD  
tRFD  
160  
45  
ns  
ns  
ns  
50pF  
50pF  
45  
RxFP  
RxDLCLK  
RxDL  
Figure 21 - Receive Data Link Functional Timing (T1 mode)  
t
RFD  
RxFP  
V
V
TT, CT  
t
RFD  
V
TT  
E1.5o  
t
RDC  
V
V
TT, CT  
RxDLCLK  
RxDL  
t
RDD  
V
V
TT, CT  
Figure 22 - Receive Data Link Diagram (T1 mode)  
142  
Preliminary Information  
MT9076  
AC Electrical Characteristics - Receive Data Link Timing (E1 mode)  
Characteristic  
Sym  
Min  
Typ  
Max Units  
Test Conditions  
50pF  
1
2
3
Data Link Clock Output Delay  
Data Link Output Delay  
RxFP Output Delay  
tRDC  
tRDD  
tRFD  
160  
45  
ns  
ns  
ns  
50pF  
50pF  
45  
RxFP  
TIME SLOT 0  
Bits 4,3,2,1,0  
Example A - 20 kb/s  
RxDLCLK  
RxDL  
Example B - 12 kb/s  
RxDLCLK  
RxDL  
Figure 23 - Receive Data Link Functional Timing (E1 mode)  
V
TT  
E2o  
t
RDC  
t
RDC  
V
V
TT, CT  
RxDLCLK  
RxDL  
t
RDD  
V
V
TT, CT  
Figure 24 - Receive Data Link Timing Diagram (E1 mode)  
143  
MT9076  
Preliminary Information  
AC Electrical Characteristics - ST-BUS Timing (E1 or T1 mode)  
Characteristic  
Sym  
Min  
Typ  
Max Units  
Test Conditions  
1
2
3
4
5
6
7
8
C4b Clock Width High or Low  
C4b Clock Width High or Low  
Frame Pulse Hold  
t4W  
tFPS  
tFPH  
tFPS  
tFPL  
tSIS  
80  
25  
10  
10  
10  
10  
10  
75  
122  
150  
35  
ns 2.048 Mb/s mode  
30.5  
ns 8.192 Mb/s mode  
ns  
Frame Pulse Setup  
Frame Pulse Low  
ns 2.048 Mb/s mode  
ns  
Serial Input Setup  
ns  
Serial Input Hold  
tSIH  
ns  
Serial Output Delay  
tSOD  
ns 150pF  
ST-BUS  
Bit Cells  
Channel 31  
Bit 0  
Channel 0  
Bit 7  
Channel 0  
Bit 6  
Channel 0  
Bit 5  
F0b  
C4b  
Figure 25 - ST-BUS Functional Timing Diagram - 2.048 Mb/s Mode  
ST-BUS  
Bit Cells  
Channel 127  
Bit 0  
Channel 0  
Bit 7  
Channel 0  
Bit 6  
Channel 0  
Bit 5  
F0b  
C4b  
Figure 26 - ST-BUS Functional Timing Diagram - 8.192 Mb/s Mode  
144  
Preliminary Information  
MT9076  
ST-BUS Bit  
Stream  
Bit Cell  
Bit Cell  
Bit Cell  
t
FPH  
F0b  
(Input)  
V
V
TT  
TT  
t
FPL  
t
FPS  
t
4WI  
t
4WI  
C4b  
(Input)  
t
SIH  
All Input  
Streams  
V
V
TT  
t
SIS  
t
SOD  
All Output  
Streams  
V
TT, CT  
Figure 27 - ST-BUS Timing Diagram (Input Clocks)  
ST-BUS Bit  
Stream  
Bit Cell  
Bit Cell  
Bit Cell  
F0b  
(Output)  
V
TT  
t
t
4WO  
FPD  
t
FPD  
C4b  
(Output)  
V
TT  
t
t
4WO  
SIH  
All Input  
Streams  
V
TT  
t
t
SIS  
SOD  
All Output  
Streams  
V
V
TT, CT  
Figure 28 - ST-BUS Timing Diagram (Output Clocks)  
145  
MT9076  
Preliminary Information  
AC Electrical Characteristics - Multiframe Timing (T1 or E1 mode)  
Characteristic  
Sym  
Min  
Typ  
Max Units  
ns 150pF  
ns  
ns * 256 C2 periods -100nsec  
Test Conditions  
1
2
3
Receive Multiframe Output Delay  
Transmit Multiframe Setup  
Transmit Multiframe Hold  
tMOD  
tMS  
50  
50  
50  
tMH  
*
Frame 0  
Bit 5 Bit 4  
Frame 12 or 24  
Bit 5 Bit 4  
DSTo  
BIt Cells  
Bit 7  
Bit 6  
Bit 0  
Bit 7  
Bit 6  
Bit 0  
Bit 7  
F0b  
C4b  
(4.096 MHz)  
RxMF  
Figure 29 - Receive Multiframe Functional Timing (T1 mode)  
Frame 15  
Frame 0  
Bit 4  
DSTo  
BIt Cells  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 0  
Bit 7  
Bit 6  
Bit 5  
Bit 0  
Bit 7  
F0b  
C4b  
(4.096 MHz)  
RxMF  
(Tx8KEN = 0)  
Figure 30 - Receive Multiframe Functional Timing (E1 mode)  
Frame N  
Frame 0  
Bit 4  
DSTi  
Bit Cells  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 0  
Bit 7  
Bit 6  
Bit 5  
Bit 0  
Bit 7  
F0b  
C4b  
(4.096 MHz)  
TxMF  
Figure 31 - Transmit Multiframe Functional Timing (T1 mode or E1 mode)  
146  
Preliminary Information  
MT9076  
V
F0b  
TT  
t
MOD  
V
TT  
C4b  
t
MOD  
(1,2)  
V
V
RxMF  
TT, CT  
t
t
MH2  
MH  
t
MS  
(1)  
V
TxMF  
TT  
Note (1) : These two signals do not have a defined phase relationship  
Note (2): Control bit Tx8KEN set low.  
Figure 32 - Multiframe Timing Diagram (T1 mode or E1 mode)  
147  
MT9076  
Preliminary Information  
AC Electrical Characteristics - TXA/TXB (E1 or T1 mode)  
Characteristic  
Serial Output Delay  
TxFP Output Delay  
Sym  
Min  
Typ  
Max  
Units  
Test Conditions  
150pF  
150pF  
1
2
tSOD  
20  
20  
ns  
ns  
tTFOD  
Channel 23  
Bit 0  
Sbit  
Channel 0  
Bit 7  
Channel 0  
Bit 6  
TXA/TXB  
RxMF/TxFP  
(Tx8KEN= 1)  
E1.5o/Exclk  
(LIUEN = 1)  
Figure 33 - TXA/TXB Functional Timing (T1 mode)  
Channel 0  
Bit 6  
Channel 0  
Bit 5  
Channel 31  
Bit 0  
Channel 0  
Bit 7  
TXA/TXB  
RxMF/TxFP  
(Tx8KEN= 1)  
E1.5o/Exclk  
(LIUEN = 1)  
Figure 34 - TXA/TXB Functional Timing (E1 mode)  
TxFP  
(Output)  
V
TT  
tTFOD  
tTFOD  
E1.5o  
V
TT  
(Output)  
t
t
SOD  
SOD  
V
TT  
TXA/TXB  
(Output)  
Figure 35 - TXA/TXB Timing Diagram (T1 mode or E1 mode)  
148  
Preliminary Information  
MT9076  
AC Electrical Characteristics - IMA Timing (E1 or T1 mode)  
Characteristic  
Sym  
Min  
Typ  
Max  
Units  
Test Conditions  
E1 mode  
1
2
3
4
5
6
C4b Clock Width High or Low  
Frame Pulse Setup  
Frame Pulse Hold  
t4W  
tFPS  
tFPS  
tSIS  
80  
10  
10  
4
122  
150  
ns  
ns  
ns  
ns  
ns  
ns  
Serial Input Setup  
Serial Input Hold  
tSIH  
tSOD  
4
Serial Output Delay  
45  
150pF  
Channel 23  
Sbit  
Channel 0  
Bit 7  
Channel 0  
Bit 6  
DSTi  
Bit 0  
F0b  
C4b  
1.544 MHz  
Figure 36 - Tx IMA Functional Timing (T1 mode)  
Channel 23  
Bit 0  
Channel 23  
Bit 1  
Sbit  
DSTo  
RXFP  
Exclk  
1.544 MHz  
Figure 37 - Rx IMA Functional Timing (T1 mode)  
Channel 31  
Bit 0  
Channel 0  
Bit 6  
Channel 0  
Bit 7  
Channel 0  
Bit 5  
DSTi  
F0b  
C4b  
2.048 MHz  
Figure 38 - Tx IMA Functional Timing (E1 mode)  
149  
MT9076  
Preliminary Information  
Channel 0  
Bit 6  
DSTo  
Channel 0  
Bit 7  
Channel 31  
Bit 0  
RXFP  
Exclk  
2.048 MHz  
Figure 39 - Rx IMA Functional Timing (E1 mode)  
ST-BUS Bit  
Stream  
Bit Cell  
Bit Cell  
F0b  
(Input)  
V
TT  
t
FPH  
t
FPS  
C4b  
(Input)  
V
TT  
t
SIS  
V
TT  
DSTi  
t
SIH  
Figure 40 - Tx IMA Timing Diagram (T1 mode or E1 mode)  
ST-BUS Bit  
Stream  
Bit Cell  
Bit Cell  
RxFP  
(Output)  
V
TT  
Exclk  
(Output)  
V
TT  
t
SIS  
V
TT  
DSTo  
t
SOD  
Figure 41 - Rx IMA Timing Diagram (T1 mode or E1 mode)  
150  
Preliminary Information  
MT9076  
1.5 ms  
FRAME  
12  
FRAME  
FRAME  
11  
FRAME  
12  
Sbit  
FRAME  
1
• • • • • • • •  
1
CHANNEL  
1
CHANNEL  
2
CHANNEL  
CHANNEL  
24  
Sbit  
• • • •  
23  
125 µs  
Least  
Significant  
Bit (Last)  
Most  
Significant  
Bit (First)  
BIT  
1
BIT  
2
BIT  
3
BIT  
4
BIT  
5
BIT  
6
BIT  
7
BIT  
8
5.2 µs  
Figure 42 - D4 Format  
2.0 ms  
FRAME  
15  
FRAME  
0
FRAME  
14  
FRAME  
15  
FRAME  
0
• • • • • • • •  
TIME SLOT  
0
TIME SLOT  
1
TIME SLOT  
30  
TIME SLOT  
31  
• • • •  
125 µs  
Least  
Significant  
Bit (Last)  
Most  
Significant  
Bit (First)  
BIT  
1
BIT  
2
BIT  
3
BIT  
4
BIT  
5
BIT  
6
BIT  
7
BIT  
8
(8/2.048) µs  
Figure 43 - PCM 30 Format  
125µs  
CHANNEL  
31  
CHANNEL  
30  
CHANNEL  
0
CHANNEL  
CHANNEL  
31  
0
• • •  
Most  
Significant  
Least  
Significant  
Bit (Last)  
BIT  
7
BIT  
6
BIT  
3
BIT  
2
BIT  
1
BIT  
5
BIT  
0
BIT  
4
Bit (First)  
3.906 µs  
Figure 44 - ST-BUS Stream Format - 2.048 Mb/s  
151  
MT9076  
Preliminary Information  
125µs  
CHANNEL  
127  
CHANNEL  
126  
CHANNEL  
0
CHANNEL  
0
CHANNEL  
127  
• • •  
Most  
Significant  
Least  
Significant  
Bit (Last)  
BIT  
0
BIT  
7
BIT  
6
BIT  
3
BIT  
2
BIT  
1
BIT  
5
BIT  
4
Bit (First)  
0.977µs  
Figure 45 - ST-BUS Stream Format 8.192 Mb/s  
152  
Preliminary Information  
MT9076  
F
A
G
D
1
D
2
D
H
E
E
1
e: (lead coplanarity)  
A
Notes:  
1
1) Not to scale  
2) Dimensions in inches  
3) (Dimensions in millimeters)  
I
E
2
4) For D & E add for allowable Mold Protrusion 0.010"  
20-Pin  
28-Pin  
44-Pin  
68-Pin  
84-Pin  
Dim  
Min  
Max  
Min  
Max  
Min  
Max  
Min  
Max  
Min  
Max  
0.165  
(4.20)  
0.180  
(4.57)  
0.165  
(4.20)  
0.180  
(4.57)  
0.165  
(4.20)  
0.180  
(4.57)  
0.165  
(4.20)  
0.200  
(5.08)  
0.165  
(4.20)  
0.200  
(5.08)  
A
0.090  
(2.29)  
0.120  
(3.04)  
0.090  
(2.29)  
0.120  
(3.04)  
0.090  
(2.29)  
0.120  
(3.04)  
0.090  
(2.29)  
0.130  
(3.30)  
0.090  
(2.29)  
0.130  
(3.30)  
A1  
0.385  
0.395  
0.485  
0.495  
0.685  
0.695  
0.985  
0.995  
1.185  
1.195  
D/E  
(9.78) (10.03) (12.32) (12.57) (17.40) (17.65) (25.02) (25.27) (30.10) (30.35)  
0.350 0.356 0.450 0.456 0.650 0.656 0.950 0.958 1.150 1.158  
(8.890) (9.042) (11.430) (11.582) (16.510) (16.662) (24.130) (24.333) (29.210) (29.413)  
D1/E1  
D2/E2  
0.290  
(7.37)  
0.330  
(8.38)  
0.390  
0.430  
0.590  
0.630  
0.890  
0.930  
1.090  
1.130  
(9.91) (10.92) (14.99) (16.00) (22.61) (23.62) (27.69) (28.70)  
0
0.004  
0
0.004  
0.032  
0
0.004  
0.032  
0
0.004  
0.032  
0
0.004  
0.032  
e
F
0.026  
0.032  
0.026  
0.026  
0.026  
0.026  
(0.661) (0.812) (0.661) (0.812) (0.661) (0.812) (0.661) (0.812) (0.661) (0.812)  
0.013 0.021 0.013 0.021 0.013 0.021 0.013 0.021 0.013 0.021  
(0.331) (0.533) (0.331) (0.533) (0.331) (0.533) (0.331) (0.533) (0.331) (0.533)  
G
H
I
0.050 BSC  
(1.27 BSC)  
0.050 BSC  
(1.27 BSC)  
0.050 BSC  
(1.27 BSC)  
0.050 BSC  
(1.27 BSC)  
0.050 BSC  
(1.27 BSC)  
0.020  
(0.51)  
0.020  
(0.51)  
0.020  
(0.51)  
0.020  
(0.51)  
0.020  
(0.51)  
Plastic J-Lead Chip Carrier - P-Suffix  
153  
MT9076  
Preliminary Information  
D
D1  
Notes:  
1) Not to scale  
E
E1  
2) Dimensions in inches  
3) (Dimensions in millimeters)  
4) Ref. JEDEC Standard MS-026  
e
A1  
A2  
A
b
80-Pin  
Max  
100-Pin  
128-Pin  
208-Pin  
256-Pin  
Dim  
A
Min  
Min  
Max  
Min  
Max  
Min  
Max  
Min  
Max  
-
0.063  
(1.60)  
-
0.063  
(1.60)  
-
0.063  
(1.60)  
-
0.063  
(1.60)  
-
0.063  
(1.60)  
A1  
A2  
b
0.002  
(0.05)  
0.006  
(0.15)  
0.002  
(0.05)  
0.006  
(0.15)  
0.002  
(0.05)  
0.006  
(0.15)  
0.002  
(0.05)  
0.006  
(0.15)  
0.002  
(0.05)  
0.006  
(0.15)  
0.053  
(1.35)  
0.057  
(1.45)  
0.053  
(1.35)  
0.057  
(1.45)  
0.053  
(1.35)  
0.057  
(1.45)  
0.053  
(1.35)  
0.057  
(1.45)  
0.053  
(1.35)  
0.057  
(1.45)  
0.009  
(0.22)  
0.015  
(0.38)  
0.001  
(0.17)  
0.011  
(0.27)  
0.001  
(0.17)  
0.011  
(0.27)  
0.001  
(0.17)  
0.011  
(0.27)  
0.005  
(0.13)  
0.009  
(0.23)  
D
0.630  
0.630  
0.866  
1.181  
1.181  
(16.00 BSC)  
(16.00 BSC)  
(22.00 BSC)  
(30.00 BSC)  
(30.00 BSC)  
D1  
e
0.551  
(14.00 BSC)  
0.551  
(14.00 BSC)  
0.787  
(20.00 BSC)  
1.102  
(28.00 BSC)  
1.102  
(28.00 BSC)  
0.025  
0.020  
0.020  
0.020  
0.016  
(0.65 BSC)  
(0.50 BSC)  
(0.50 BSC)  
(0.50 BSC)  
(0.40 BSC)  
E
0.630  
0.630  
0.630  
1.181  
1.181  
(16.00 BSC)  
(16.00 BSC)  
(16.00 BSC)  
(30.00 BSC)  
(30.0 BSC)  
E1  
0.551  
0.551  
0.551  
1.102  
1.102  
(14.00 BSC)  
(14.00 BSC)  
(14.00 BSC)  
(28.00 BSC)  
(28.00 BSC)  
LQFP - B Suffix  
154  
Preliminary Information  
MT9076  
Notes:  
155  
http://www.mitelsemi.com  
World Headquarters - Canada  
Tel: +1 (613) 592 2122  
Fax: +1 (613) 592 6909  
North America  
Tel: +1 (770) 486 0194  
Fax: +1 (770) 631 8213  
Asia/Pacific  
Tel: +65 333 6193  
Fax: +65 333 6192  
Europe, Middle East,  
and Africa (EMEA)  
Tel: +44 (0) 1793 518528  
Fax: +44 (0) 1793 518581  
Information relating to products and services furnished herein by Mitel Corporation or its subsidiaries (collectively “Mitel”) is believed to be reliable. However, Mitel assumes no  
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Purchasers of products are also hereby notified that the use of product in certain ways or in combination with Mitel, or non-Mitel furnished goods or services may infringe patents or  
other intellectual property rights owned by Mitel.  
This publication is issued to provide information only and (unless agreed by Mitel in writing) may not be used, applied or reproduced for any purpose nor form part of any order or  
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piece of equipment. It is the user’s responsibility to fully determine the performance and suitability of any equipment using such information and to ensure that any publication or  
data used is up to date and has not been superseded. Manufacturing does not necessarily include testing of all functions or parameters. These products are not suitable for use in  
any medical products whose failure to perform may result in significant injury or death to the user. All products and materials are sold and services provided subject to Mitel’s  
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Copyright 1999 MITEL Corporation  
All Rights Reserved  
Printed in CANADA  
TECHNICAL DOCUMENTATION - NOT FOR RESALE  

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