CY7C027-12AC [CYPRESS]
32K/64K x 16/18 Dual-Port Static RAM; 32K / 64K X 16/18双端口静态RAM型号: | CY7C027-12AC |
厂家: | CYPRESS |
描述: | 32K/64K x 16/18 Dual-Port Static RAM |
文件: | 总19页 (文件大小:258K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
25/0251
CY7C027/028
CY7C037/038
32K/64K x 16/18
Dual-Port Static RAM
• Fully asynchronous operation
Features
• Automatic power-down
• Expandable data bus to 32/36 bits or more using Mas-
ter/Slave chip select when using more than one device
• True Dual-Ported memory cells which allow simulta-
neous access of the same memory location
• 32K x 16 organization (CY7C027)
• 64K x 16 organization (CY7C028)
• 32K x 18 organization (CY7C037)
• 64K x 18 organization (CY7C038)
• 0.35-micron CMOS for optimum speed/power
• High-speed access: 12[1]/15/20 ns
• Low operating power
• On-chip arbitration logic
• Semaphores included to permit software handshaking
between ports
• INT flags for port-to-port communication
• Separate upper-byte and lower-byte control
• Dual Chip Enables
• Pin select for Master or Slave
— Active: ICC = 180 mA (typical)
• Commercial and industrial temperature ranges
• Available in 100-pin TQFP
— Standby: ISB3 = 0.05 mA (typical)
• Pin-compatible and functionally equivalent to IDT7027
Logic Block Diagram
R/WL
UBL
R/WR
UBR
CE0L
CE0R
CE1L
CE1R
CEL
CER
LBL
LBR
OEL
OER
8/9
[2]
8/9
8/9
[2]
I/O8/9L–I/O15/17L
I/O8/9L–I/O15/17R
8/9
[3]
[3]
I/O
Control
I/O
Control
I/O0L–I/O7/8L
I/O0L–I/O7/8R
15/16
[4]
15/16
[4]
Address
Decode
Address
Decode
True Dual-Ported
A0L–A
A
0R–A14/15R
14/15L
RAM Array
15/16
15/16
[4]
[4]
A0L–A
A0R–A14/15R
14/15L
CEL
CER
Interrupt
Semaphore
Arbitration
OEL
OER
R/WL
SEML
BUSYL[5]
R/WR
SEMR
[5] BUSYR
INTR
INTL
UBL
UBR
LBL
M/S
LBR
Notes:
1. See page 6 for Load Conditions.
2. I/O8–I/O15 for x16 devices; I/O9–I/O17 for x18 devices.
3. I/O0–I/O7 for x16 devices; I/O0–I/O8 for x18 devices.
4. A0–A14 for 32K; A0–A15 for 64K devices.
5. BUSY is an output in master mode and an input in slave mode.
For the most recent information, visit the Cypress web site at www.cypress.com
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose
•
CA 95134
•
408-943-2600
Document #: 38-06042 Rev. *A
Revised December 27, 2002
CY7C027/028
CY7C037/038
Each port has independent control pins: dual chip enables
(CE0 and CE1), read or write enable (R/W), and output enable
(OE). Two flags are provided on each port (BUSY and INT). BUSY
signals that the port is trying to access the same location currently
being accessed by the other port. The interrupt flag (INT) permits
communication between ports or systems by means of a mail box.
The semaphores are used to pass a flag, or token, from one port to
the other to indicate that a shared resource is in use. The semaphore
logic is comprised of eight shared latches. Only one side can control
the latch (semaphore) at any time. Control of a semaphore indicates
that a shared resource is in use. An automatic power-down feature is
controlled independently on each port by the chip enable pins.
Functional Description
The CY7C027/028 and CY7C037/038 are low-power CMOS
32K, 64K x 16/18 dual-port static RAMs. Various arbitration
schemes are included on the devices to handle situations
when multiple processors access the same piece of data. Two
ports are provided, permitting independent, asynchronous ac-
cess for reads and writes to any location in memory. The de-
vices can be utilized as standalone 16/18-bit dual-port static
RAMs or multiple devices can be combined in order to function
as a 32/36-bit or wider master/slave dual-port static RAM. An
M/S pin is provided for implementing 32/36-bit or wider mem-
ory applications without the need for separate master and
slave devices or additional discrete logic. Application areas
include interprocessor/multiprocessor designs, communica-
tions status buffering, and dual-port video/graphics memory.
The CY7C027/028 and CY7C037/038 are available in 100-pin
Thin Quad Plastic Flatpack (TQFP) packages.
Pin Configurations
100-Pin TQFP (Top View)
100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76
A9L
A10L
A11L
1
2
3
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
A9R
A10R
A11R
A12R
A13R
A14R
A15R
NC
A12L
A13L
A14L
A15L
NC
4
5
6
[6]
[6]
7
8
NC
9
NC
LBL
10
11
12
13
14
15
16
17
18
19
20
21
22
23
LBR
UBL
UBR
CE0R
CE1R
CE0L
CE1L
SEML
VCC
CY7C028 (64K x 16)
CY7C027 (32K x 16)
SEMR
GND
R/WL
OEL
R/WR
OER
GND
GND
I/O15L
I/O14L
I/O13L
I/O12L
GND
GND
I/O15R
I/O14R
I/O13R
I/O12R
I/O11R
I/O10R
I/O11L
I/O10L
24
25
26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
Note:
6. This pin is NC for CY7C027.
Document #: 38-06042 Rev. *A
Page 2 of 19
CY7C027/028
CY7C037/038
Pin Configurations (continued)
100-Pin TQFP (Top View)
100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76
A9L
A10L
A11L
A12L
A13L
A14L
A15L
LBL
1
75
74
73
72
A8R
2
A9R
3
A10R
A11R
4
5
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
A12R
A13R
A14R
6
[7]
7
[7]
8
A15R
LBR
UBL
9
CE0L
CE1L
SEML
R/WL
OEL
10
11
12
13
14
15
16
17
18
19
20
21
22
23
UBR
CE0R
CE1R
CY7C038 (64K x 18)
CY7C037 (32K x 18)
SEMR
R/WR
GND
VCC
GND
OER
I/O17L
I/O16L
GND
GND
I/O17R
GND
I/O15L
I/O14L
I/O13L
I/O12L
I/O16R
I/O15R
I/O14R
I/O13R
I/O12R
I/O11R
I/O11L
I/O10L
24
25
26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
Selection Guide
CY7C027/028
CY7C037/038
-12[1]
CY7C027/028
CY7C037/038
-15
CY7C027/028
CY7C037/038
-20
Maximum Access Time (ns)
12
195
55
15
190
50
20
180
45
Typical Operating Current (mA)
Typical Standby Current for ISB1 (mA) (Both ports TTL level)
Typical Standby Current for ISB3 (mA) (Both ports CMOS level)
0.05
0.05
0.05
Note:
7. This pin is NC for CY7C037.
Document #: 38-06042 Rev. *A
Page 3 of 19
CY7C027/028
CY7C037/038
Pin Definitions
Left Port
CE0L, CE1L
R/WL
Right Port
CE0R, CE1R
Description
Chip Enable (CE is LOW when CE0 ≤ VIL and CE1 ≥ VIH)
R/WR
Read/Write Enable
OEL
OER
Output Enable
A0L–A15L
I/O0L–I/O17L
SEML
A0R–A15R
I/O0R–I/O17R
SEMR
UBR
Address (A0–A14 for 32K; A0–A15 for 64K devices)
Data Bus Input/Output (I/O0–I/O15 for x16 devices; I/O0–I/O17 for x18)
Semaphore Enable
UBL
Upper Byte Select (I/O8–I/O15 for x16 devices; I/O9–I/O17 for x18 devices)
LBL
LBR
Lower Byte Select (I/O0–I/O7 for x16 devices; I/O0–I/O8 for x18 devices)
INTL
INTR
Interrupt Flag
Busy Flag
BUSYL
M/S
BUSYR
Master or Slave Select
Power
VCC
GND
Ground
NC
No Connect
Input Voltage[9] ...............................................–0.5V to +7.0V
Maximum Ratings[8]
Output Current into Outputs (LOW)............................. 20 mA
(Above which the useful life may be impaired. For user guide-
lines, not tested.)
Static Discharge Voltage........................................... >1100V
Latch-Up Current.................................................... >200 mA
Storage Temperature .................................–65°C to +150°C
Ambient Temperature with
Power Applied.............................................–55°C to +125°C
Operating Range
Ambient
Supply Voltage to Ground Potential............... –0.3V to +7.0V
Range
Commercial
Industrial[10]
Temperature
0°C to +70°C
–40°C to +85°C
VCC
DC Voltage Applied to Outputs
in High Z State ............................................ –0.5V to +7.0DC
5V ± 10%
5V ± 10%
Note:
8. The Voltage on any input or I/O pin cannot exceed the power pin during power-up.
9. Pulse width < 20 ns.
10. Industrial parts are available in CY7C028 and CY7C038 only.
Document #: 38-06042 Rev. *A
Page 4 of 19
CY7C027/028
CY7C037/038
Electrical Characteristics Over the Operating Range
CY7C027/028
CY7C037/038
-12[1]
-15
-20
Symbol
Parameter
Min. Typ. Max. Min. Typ. Max. Min. Typ. Max. Unit
VOH
Output HIGH Voltage (VCC=Min.,
IOH= –4.0 mA)
2.4
2.4
2.4
V
VOL
Output LOW Voltage (VCC=Min.,
IOH= +4.0 mA)
0.4
0.4
0.4
V
VIH
VIL
IOZ
ICC
Input HIGH Voltage
Input LOW Voltage
2.2
2.2
2.2
V
0.8
10
0.8
10
0.8
10
V
Output Leakage Current
–10
–10
–10
µA
mA
mA
Operating Current
(VCC=Max, IOUT=0 mA)
Outputs Disabled
Com’l.
Ind.[10]
195
55
325
190
50
280
180
305
265
290
ISB1
ISB2
ISB3
ISB4
Standby Current (Both
PortsTTLLevel)CEL &CER
≥ VIH, f=fMAX
Com’l.
Ind.[10]
75
70
45
60
65
80
mA
mA
Standby Current (One Port Com’l.
TTL Level) CEL | CER ≥ VIH,
f=fMAX
125
0.05
115
205
0.5
120
0.05
110
180
0.5
160
110
125
160
175
mA
mA
Ind.[10]
Standby Current (Both
Ports CMOS Level) CEL &
CER ≥ VCC – 0.2V, f=0
Com’l.
Ind.[10]
0.05
0.05
0.5
0.5
mA
mA
Standby Current (One Port Com’l.
185
100
115
140
155
mA
mA
CMOS Level) CEL | CER
≥
Ind.[10]
[11]
VIH, f=fMAX
Note:
11.
f
MAX = 1/tRC = All inputs cycling at f = 1/tRC (except output enable). f = 0 means no address or control lines change. This applies only to inputs at CMOS level standby ISB3
.
Document #: 38-06042 Rev. *A
Page 5 of 19
CY7C027/028
CY7C037/038
Capacitance[12]
Parameter
CIN
Description
Input Capacitance
Output Capacitance
Test Conditions
TA = 25°C, f = 1 MHz,
Max.
10
Unit
pF
VCC = 5.0V
COUT
10
pF
AC Test Loads and Waveforms
5V
5V
R
TH
= 250Ω
R1 = 893Ω
OUTPUT
C = 30 pF
OUTPUT
R1 = 893Ω
OUTPUT
C = 5 pF
C = 30 pF
R2 = 347Ω
R2 = 347Ω
V
TH
= 1.4V
(a) Normal Load (Load 1)
(c) Three-State Delay(Load 2)
(Used for tCKLZ, tOLZ, & tOHZ
including scope and jig)
(b) Thévenin Equivalent (Load 1)
ALL INPUTPULSES
3.0V
GND
90%
90%
10%
3 ns
10%
3 ns
≤
≤
AC Test Loads (Applicable to -12 only)[13]
1.00
0.90
Z = 50
Ω
R = 50Ω
0
OUTPUT
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
C
V
TH
= 1.4V
(a) Load 1 (-12 only)
0
5
10
15
20
25
30
(pF)
Capacitance
(b) Load Derating Curve
Notes:
12. Tested initially and after any design or process changes that may affect these parameters.
13. Test Conditions: C = 0 pF.
Document #: 38-06042 Rev. *A
Page 6 of 19
CY7C027/028
CY7C037/038
Switching Characteristics Over the Operating Range[14]
CY7C027/028
CY7C037/038
-12[1]
Max.
-15
-20
Parameter
Description
Min.
12
3
Min.
15
Max.
Min.
20
Max.
Unit
READ CYCLE
tRC
Read Cycle Time
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
tAA
Address to Data Valid
Output Hold From Address Change
CE LOW to Data Valid
OE LOW to Data Valid
OE LOW to Low Z
12
15
20
tOHA
3
3
[15]
tACE
tDOE
tLZOE
12
8
15
10
20
12
[16, 17, 18]
[16, 17, 18]
3
3
0
3
3
0
3
3
0
tHZOE
OE HIGH to High Z
10
10
10
10
12
12
[16, 17, 18]
tLZCE
CE LOW to Low Z
[16, 17, 18]
tHZCE
CE HIGH to High Z
[18]
[18]
tPU
tPD
CE LOW to Power-Up
CE HIGH to Power-Down
Byte Enable Access Time
12
12
15
15
20
20
[15]
tABE
WRITE CYCLE
tWC
Write Cycle Time
12
10
10
0
15
12
12
0
20
15
15
0
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
[15]
tSCE
tAW
tHA
CE LOW to Write End
Address Valid to Write End
Address Hold From Write End
Address Set-Up to Write Start
Write Pulse Width
[15]
tSA
tPWE
tSD
0
0
0
10
10
0
12
10
0
15
15
0
Data Set-Up to Write End
Data Hold From Write End
R/W LOW to High Z
tHD
[17, 18]
tHZWE
10
10
12
[17, 18]
tLZWE
R/W HIGH to Low Z
3
3
3
[19]
tWDD
Write Pulse to Data Delay
Write Data Valid to Read Data Valid
25
20
30
25
45
30
[19]
tDDD
Notes:
14. Test conditions assume signal transition time of 3 ns or less, timing reference levels of 1.5V, input pulse levels of 0 to 3.0V, and output loading of the specified
IOI/IOH and 30-pF load capacitance.
15. To access RAM, CE=L, UB=L, SEM=H. To access semaphore, CE=H and SEM=L. Either condition must be valid for the entire tSCE time.
16. At any given temperature and voltage condition for any given device, tHZCE is less than tLZCE and tHZOE is less than tLZOE
.
17. Test conditions used are Load 2.
18. This parameter is guaranteed by design, but it is not production tested.
19. For information on port-to-port delay through RAM cells from writing port to reading port, refer to Read Timing with Busy waveform.
Document #: 38-06042 Rev. *A
Page 7 of 19
CY7C027/028
CY7C037/038
Switching Characteristics Over the Operating Range[14] (continued)
CY7C027/028
CY7C037/038
-12[1]
-15
-20
Parameter
Description
Min.
Max.
Min.
Max.
Min.
Max.
Unit
BUSY TIMING[20]
tBLA
tBHA
tBLC
tBHC
tPS
BUSY LOW from Address Match
BUSY HIGH from Address Mismatch
BUSY LOW from CE LOW
BUSY HIGH from CE HIGH
Port Set-Up for Priority
12
12
12
12
15
15
15
15
20
20
20
17
ns
ns
ns
ns
ns
ns
ns
ns
5
0
5
0
5
0
tWB
R/W HIGH after BUSY (Slave)
R/W HIGH after BUSY HIGH (Slave)
BUSY HIGH to Data Valid
tWH
11
13
15
[21]
tBDD
12
15
20
INTERRUPT TIMING[20]
tINS
INT Set Time
12
12
15
15
20
20
ns
ns
tINR
INT Reset Time
SEMAPHORE TIMING
tSOP
tSWRD
tSPS
SEM Flag Update Pulse (OE or SEM)
SEM Flag Write to Read Time
SEM Flag Contention Window
SEM Address Access Time
10
5
10
5
10
5
ns
ns
ns
ns
5
5
5
tSAA
12
15
20
Timing
Data Retention Mode
Data Retention Mode
4.5V
The CY7C027/028 and CY7C037/038 are designed with bat-
tery backup in mind. Data retention voltage and supply current
are guaranteed over temperature. The following rules ensure
data retention:
V
CC
4.5V
V
CC
> 2.0V
t
RC
1. Chip enable (CE) must be held HIGH during data retention, with-
in VCC to VCC – 0.2V.
V
CC
to V – 0.2V
CC
V
IH
CE
2. CE must be kept between VCC – 0.2V and 70% of VCC
during the power-up and power-down transitions.
3. The RAM can begin operation >tRC after VCC reaches the
minimum operating voltage (4.5 volts).
Parameter
Test Conditions[22]
Max.
Unit
ICCDR1
@ VCCDR = 2V
1.5
mA
Notes:
20. Test conditions used are Load 1.
21.
tBDD is a calculated parameter and is the greater of tWDD–tPWE (actual) or tDDD–tSD (actual).
22. CE = VCC, Vin = GND to VCC, TA = 25°C. This parameter is guaranteed but not tested.
Document #: 38-06042 Rev. *A
Page 8 of 19
CY7C027/028
CY7C037/038
Switching Waveforms
Read Cycle No. 1 (Either Port Address Access)[23 ,24, 25]
t
RC
ADDRESS
DATA OUT
t
AA
t
t
OHA
OHA
PREVIOUS DATAVALID
DATA VALID
Read Cycle No. 2 (Either Port CE/OE Access)[23, 26, 27]
t
ACE
CE and
LB or UB
t
HZCE
t
DOE
OE
t
HZOE
t
LZOE
DATA VALID
DATA OUT
t
LZCE
t
PU
t
PD
I
CC
CURRENT
I
SB
Read Cycle No. 3 (Either Port)[23, 25, 26, 27]
t
RC
ADDRESS
t
AA
t
OHA
UB or LB
t
t
HZCE
t
LZCE
LZCE
t
ABE
CE
HZCE
t
ACE
t
DATA OUT
Notes:
23. R/W is HIGH for read cycles.
24. Device is continuously selected CE = VIL and UB or LB = VIL. This waveform cannot be used for semaphore reads.
25. OE = VIL
.
26. Address valid prior to or coincident with CE transition LOW.
27. To access RAM, CE = VIL, UB or LB = VIL, SEM = VIH. To access semaphore, CE = VIH, SEM = VIL.
Document #: 38-06042 Rev. *A
Page 9 of 19
CY7C027/028
CY7C037/038
Switching Waveforms (continued)
Write Cycle No. 1: R/W Controlled Timing[28, 29, 30, 31]
t
WC
ADDRESS
OE
[34]
t
HZOE
t
AW
[32,33]
CE
[31]
PWE
t
SA
t
t
HA
R/W
DATAOUT
DATA IN
[34]
HZWE
t
t
LZWE
NOTE 35
NOTE 35
t
t
HD
SD
Write Cycle No. 2: CE Controlled Timing[28, 29, 30, 34, 35]
t
WC
ADDRESS
t
AW
[32,33]
CE
t
SA
t
t
HA
SCE
R/W
t
t
HD
SD
DATA IN
Notes:
28. R/W must be HIGH during all address transitions.
29. A write occurs during the overlap (tSCE or tPWE) of a LOW CE or SEM and a LOW UB or LB.
30. tHA is measured from the earlier of CE or R/W or (SEM or R/W) going HIGH at the end of write cycle.
31. If OE is LOW during a R/W controlled write cycle, the write pulse width must be the larger of tPWE or (tHZWE + tSD) to allow the I/O drivers to turn off and data to be placed on
the bus for the required tSD. If OE is HIGH during an R/W controlled write cycle, this requirement does not apply and the write pulse can be as short as the specified tPWE
.
32. To access RAM, CE = VIL, SEM = VIH
33. To access upper byte, CE = VIL, UB = VIL, SEM = VIH
To access lower byte, CE = VIL, LB = VIL, SEM = VIH
.
.
.
34. Transition is measured ±500 mV from steady state with a 5-pF load (including scope and jig). This parameter is sampled and not 100% tested.
35. During this period, the I/O pins are in the output state, and input signals must not be applied.
36. If the CE or SEM LOW transition occurs simultaneously with or after the R/W LOW transition, the outputs remain in the high-impedance state.
Document #: 38-06042 Rev. *A
Page 10 of 19
CY7C027/028
CY7C037/038
Switching Waveforms (continued)
Semaphore Read After Write Timing, Either Side[37]
t
t
OHA
SAA
A –A
0
VALID ADRESS
VALID ADRESS
2
t
AW
t
ACE
t
HA
SEM
t
t
SOP
SCE
t
SD
I/O
0
DATA VALID
DATA
VALID
IN
OUT
t
HD
t
SA
t
PWE
R/W
OE
t
t
DOE
SWRD
t
SOP
WRITE CYCLE
READ CYCLE
Timing Diagram of Semaphore Contention[38, 39, 40]
A
–A
2L
0L
MATCH
R/W
L
SEM
L
t
SPS
A
–A
2R
0R
MATCH
R/W
R
SEM
R
Notes:
37. CE = HIGH for the duration of the above timing (both write and read cycle).
38. I/O0R = I/O0L = LOW (request semaphore); CER = CEL = HIGH.
39. Semaphores are reset (available to both ports) at cycle start.
40. If tSPS is violated, the semaphore will definitely be obtained by one side or the other, but which side will get the semaphore is unpredictable.
Document #: 38-06042 Rev. *A
Page 11 of 19
CY7C027/028
CY7C037/038
Switching Waveforms (continued)
Timing Diagram of Read with BUSY (M/S=HIGH)[41]
t
WC
ADDRESS
R
MATCH
t
PWE
R/W
R
t
t
HD
SD
DATA IN
VALID
R
t
PS
ADDRESS
L
MATCH
t
BLA
t
BHA
BUSY
L
t
BDD
t
DDD
DATA
VALID
OUTL
t
WDD
Write Timing with Busy Input (M/S=LOW)
t
PWE
R/W
t
t
WH
WB
BUSY
Note:
41. CEL = CER = LOW.
Document #: 38-06042 Rev. *A
Page 12 of 19
CY7C027/028
CY7C037/038
Switching Waveforms (continued)
Busy Timing Diagram No.1 (CE Arbitration)[42]
CELValid First:
ADDRESS
L,R
ADDRESS MATCH
CE
L
t
PS
CE
R
t
t
BHC
BLC
BUSY
R
CER ValidFirst:
ADDRESS
L,R
ADDRESS MATCH
CE
R
t
PS
CE
L
L
t
t
BHC
BLC
BUSY
Busy Timing Diagram No. 2 (Address Arbitration)[42]
Left Address Valid First:
t
or t
WC
RC
ADDRESS
L
ADDRESS MATCH
ADDRESS MISMATCH
t
PS
ADDRESS
R
t
t
BHA
BLA
BUSY
R
Right AddressValid First:
t
or t
WC
RC
ADDRESS
R
ADDRESS MATCH
ADDRESS MISMATCH
t
PS
ADDRESS
L
t
t
BHA
BLA
BUSY
L
Note:
42. If tPS is violated, the busy signal will be asserted on one side or the other, but there is no guarantee to which side BUSY will be asserted.
Document #: 38-06042 Rev. *A
Page 13 of 19
CY7C027/028
CY7C037/038
Switching Waveforms (continued)
Interrupt Timing Diagrams
Left Side Sets INTR:
t
WC
ADDRESS
WRITE 7FFF (FFFF for CY7C028/38)
[43]
L
t
HA
CE
L
R/W
INT
L
R
[44]
t
INS
Right Side Clears INTR:
t
RC
READ 7FFF
(FFFF for CY7C028/38)
ADDRESS
R
CE
R
[44]
t
INR
R/W
R
OE
R
INT
R
:
Right SideSets INTL
t
WC
ADDRESS
R
WRITE 7FFE (FFFE for CY7C028/38)
[43]
t
HA
CE
R
R
R/W
INT
L
[44]
INS
t
Left Side Clears INTL:
t
RC
READ 7FFE
(FFFE for CY7C028/38)
ADDRESS
CE
R
L
[44]
t
INR
R/W
L
OE
INT
L
L
Notes:
43.
tHA depends on which enable pin (CEL or R/WL) is deasserted first.
44. tINS or tINR depends on which enable pin (CEL or R/WL) is asserted last.
Document #: 38-06042 Rev. *A
Page 14 of 19
CY7C027/028
CY7C037/038
tion). If both ports’ CEs are asserted and an address match occurs
within tPS of each other, the busy logic will determine which port has
access. If tPS is violated, one port will definitely gain permission to the
location, but it is not predictable which port will get that permission.
BUSY will be asserted tBLA after an address match or tBLC after CE
is taken LOW.
Architecture
The CY7C027/028 and CY7C037/038 consist of an array of
32K and 64K words of 16 and 18 bits each of dual-port RAM
cells, I/O and address lines, and control signals (CE, OE, R/W).
These control pins permit independent access for reads or writes to
any location in memory. To handle simultaneous writes/reads to the
same location, a BUSY pin is provided on each port. Two interrupt
(INT) pins can be utilized for port-to-port communication. Two sema-
phore (SEM) control pins are used for allocating shared resources.
With the M/S pin, the devices can function as a master (BUSY pins
are outputs) or as a slave (BUSY pins are inputs). The devices also
have an automatic power-down feature controlled by CE. Each port
is provided with its own output enable control (OE), which allows data
to be read from the device.
Master/Slave
A M/S pin is provided in order to expand the word width by configur-
ing the device as either a master or a slave. The BUSY output of the
master is connected to the BUSY input of the slave. This will allow the
device to interface to a master device with no external components.
Writing to slave devices must be delayed until after the BUSY input
has settled (tBLC or tBLA), otherwise, the slave chip may begin a write
cycle during a contention situation. When tied HIGH, the M/S pin al-
lows the device to be used as a master and, therefore, the BUSY line
is an output. BUSY can then be used to send the arbitration outcome
to a slave.
Functional Description
Write Operation
Semaphore Operation
Data must be set up for a duration of tSD before the rising edge
of R/W in order to guarantee a valid write. A write operation is con-
trolled by either the R/W pin (see Write Cycle No. 1 waveform) or the
CE pin (see Write Cycle No. 2 waveform). Required inputs for
non-contention operations are summarized in Table 1.
The CY7C027/028 and CY7C037/038 provide eight sema-
phore latches, which are separate from the dual-port memory
locations. Semaphores are used to reserve resources that are
shared between the two ports.The state of the semaphore in-
dicates that a resource is in use. For example, if the left port
wants to request a given resource, it sets a latch by writing a
zero to a semaphore location. The left port then verifies its
success in setting the latch by reading it. After writing to the
semaphore, SEM or OE must be deasserted for tSOP before at-
tempting to read the semaphore. The semaphore value will be avail-
able tSWRD + tDOE after the rising edge of the semaphore write. If the
left port was successful (reads a zero), it assumes control of the
shared resource, otherwise (reads a one) it assumes the right port
has control and continues to poll the semaphore. When the right side
has relinquished control of the semaphore (by writing a one), the left
side will succeed in gaining control of the semaphore. If the left side
no longer requires the semaphore, a one is written to cancel its re-
quest.
If a location is being written to by one port and the opposite
port attempts to read that location, a port-to-port flowthrough
delay must occur before the data is read on the output; other-
wise the data read is not deterministic. Data will be valid on the
port tDDD after the data is presented on the other port.
Read Operation
When reading the device, the user must assert both the OE
and CE pins. Data will be available tACE after CE or tDOE after OE is
asserted. If the user wishes to access a semaphore flag, then the
SEM pin must be asserted instead of the CE pin, and OE must also
be asserted.
Interrupts
Semaphores are accessed by asserting SEM LOW. The SEM
pin functions as a chip select for the semaphore latches (CE must
remain HIGH during SEM LOW). A0–2 represents the semaphore
address. OE and R/W are used in the same manner as a normal
memory access. When writing or reading a semaphore, the other
address pins have no effect.
The upper two memory locations may be used for message
passing. The highest memory location (7FFF for the
CY7C027/37, FFFF for the CY7C028/38) is the mailbox for the
right port and the second-highest memory location (7FFE for
the CY7C027/37, FFFE for the CY7C028/38) is the mailbox for
the left port. When one port writes to the other port’s mailbox,
an interrupt is generated to the owner. The interrupt is reset
when the owner reads the contents of the mailbox. The mes-
sage is user defined.
When writing to the semaphore, only I/O0 is used. If a zero is
written to the left port of an available semaphore, a one will appear at
the same semaphore address on the right port. That semaphore can
now only be modified by the side showing zero (the left port in this
case). If the left port now relinquishes control by writing a one to the
semaphore, the semaphore will be set to one for both sides. Howev-
er, if the right port had requested the semaphore (written a zero) while
the left port had control, the right port would immediately own the
semaphore as soon as the left port released it. Table 3 shows sam-
ple semaphore operations.
Each port can read the other port’s mailbox without resetting
the interrupt. The active state of the busy signal (to a port)
prevents the port from setting the interrupt to the winning port.
Also, an active busy to a port prevents that port from reading
its own mailbox and, thus, resetting the interrupt to it.
If an application does not require message passing, do not
connect the interrupt pin to the processor’s interrupt request
input pin.
When reading a semaphore, all sixteen/eighteen data lines
output the semaphore value. The read value is latched in an
output register to prevent the semaphore from changing state
during a write from the other port. If both ports attempt to ac-
cess the semaphore within tSPS of each other, the semaphore will
definitely be obtained by one side or the other, but there is no guaran-
tee which side will control the semaphore.
The operation of the interrupts and their interaction with Busy
is summarized in Table 2.
Busy
The CY7C027/028 and CY7C037/038 provide on-chip arbitra-
tion to resolve simultaneous memory location access (conten-
Document #: 38-06042 Rev. *A
Page 15 of 19
CY7C027/028
CY7C037/038
Table 1. Non-Contending Read/Write
Inputs
Outputs
CE
H
X
L
R/W
X
OE
X
X
X
X
X
L
UB
X
H
L
LB
X
H
H
L
SEM
H
H
H
H
H
H
H
H
X
I/O9–I/O17
High Z
I/O0–I/O8
High Z
Operation
Deselected: Power-Down
X
High Z
High Z
Deselected: Power-Down
Write to Upper Byte Only
Write to Lower Byte Only
Write to Both Bytes
L
Data In
High Z
High Z
L
L
H
L
Data In
Data In
High Z
L
L
L
Data In
Data Out
High Z
L
H
H
H
X
L
H
L
Read Upper Byte Only
Read Lower Byte Only
Read Both Bytes
L
L
H
L
Data Out
Data Out
High Z
L
L
L
Data Out
High Z
X
H
X
H
H
L
X
X
H
X
X
X
H
X
Outputs Disabled
H
H
L
Data Out
Data Out
Data In
Data Out
Data Out
Data In
Read Data in Semaphore Flag
Read Data in Semaphore Flag
Write DIN0 into Semaphore Flag
L
L
X
L
X
X
H
H
L
Data In
Data In
Write DIN0 into Semaphore Flag
L
L
X
X
X
X
L
X
L
L
L
Not Allowed
Not Allowed
X
Table 2. Interrupt Operation Example (assumes BUSYL=BUSYR=HIGH)[45]
Left Port
Right Port
Function
R/WL CEL
OEL
X
A0L–14L
7FFF
X
INTL R/WR CER
OER
X
A0R–14R
X
INTR
L[47]
H[46]
X
Set Right INTR Flag
Reset Right INTR Flag
Set Left INTL Flag
Reset Left INTL Flag
L
X
X
X
L
X
X
L
X
X
X
L
X
L
L
X
X
X
L
7FFF
7FFE
X
X
X
L[46]
H[47]
X
L
7FFE
X
X
X
Table 3. Semaphore Operation Example
Function I/O0–I/O17 Left I/O0–I/O17 Right
Status
No action
1
0
0
1
1
0
1
1
1
0
1
1
1
1
0
0
1
1
0
1
1
1
Semaphore free
Left Port has semaphore token
Left port writes 0 to semaphore
Right port writes 0 to semaphore
Left port writes 1 to semaphore
Left port writes 0 to semaphore
Right port writes 1 to semaphore
Left port writes 1 to semaphore
Right port writes 0 to semaphore
Right port writes 1 to semaphore
Left port writes 0 to semaphore
No change. Right side has no write access to semaphore
Right port obtains semaphore token
No change. Left port has no write access to semaphore
Left port obtains semaphore token
Semaphore free
Right port has semaphore token
Semaphore free
Left port has semaphore token
Semaphore free
Left port writes 1 to semaphore
Notes:
45. A0L–15L and A0R–15R, FFFF/FFFE for the CY7C028/038.
46. If BUSYR=L, then no change.
47. If BUSYL=L, then no change.
Document #: 38-06042 Rev. *A
Page 16 of 19
CY7C027/028
CY7C037/038
Ordering Information
32K x16 Asynchronous Dual-Port SRAM
Speed
Package
Name
Operating
Range
(ns)
12[1]
15
Ordering Code
CY7C027-12AC
Package Type
100-Pin Thin Quad Flat Pack
100-Pin Thin Quad Flat Pack
100-Pin Thin Quad Flat Pack
A100
A100
A100
Commercial
Commercial
Commercial
CY7C027-15AC
CY7C027-20AC
20
64K x16 Asynchronous Dual-Port SRAM
Speed
Package
Name
Operating
Range
(ns)
12[1]
15
Ordering Code
Package Type
100-Pin Thin Quad Flat Pack
100-Pin Thin Quad Flat Pack
100-Pin Thin Quad Flat Pack
100-Pin Thin Quad Flat Pack
CY7C028-12AC
A100
A100
A100
A100
Commercial
Commercial
Commercial
Industrial
CY7C028-15AC
CY7C028-20AC
CY7C028-20AI
20
32K x18 Asynchronous Dual-Port SRAM
Speed
Package
Name
Operating
Range
(ns)
12[1]
15
Ordering Code
Package Type
100-Pin Thin Quad Flat Pack
100-Pin Thin Quad Flat Pack
100-Pin Thin Quad Flat Pack
CY7C037-12AC
A100
A100
A100
Commercial
Commercial
Commercial
CY7C037-15AC
CY7C037-20AC
20
64K x18 Asynchronous Dual-Port SRAM
Speed
Package
Name
Operating
Range
(ns)
12[1]
15
Ordering Code
Package Type
100-Pin Thin Quad Flat Pack
100-Pin Thin Quad Flat Pack
100-Pin Thin Quad Flat Pack
100-Pin Thin Quad Flat Pack
CY7C038-12AC
A100
A100
A100
A100
Commercial
Commercial
Commercial
Industrial
CY7C038-15AC
CY7C038-20AC
CY7C038-20AI
20
Document #: 38-06042 Rev. *A
Page 17 of 19
CY7C027/028
CY7C037/038
Package Diagram
100-Pin Thin Plastic Quad Flat Pack (TQFP) A100
51-85048-A
Document #: 38-06042 Rev. *A
Page 18 of 19
© Cypress Semiconductor Corporation, 2001. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use
of any circuitry other than circuitry embodied in a Cypress Semiconductor product. Nor does it convey or imply any license under patent or other rights. Cypress Semiconductor does not authorize
its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress
Semiconductor products in life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress Semiconductor against all charges.
CY7C027/028
CY7C037/038
Document Title: CY7C027/028, CY7C037/038 32K/64K x 16/18 Dual-Port Static RAM
Document Number: 38-06042
Issue
Orig. of
Change
REV.
**
ECN NO. Date
Description of Change
110190
122292
09/29/01
12/27/02
SZV
RBI
Change from Spec number: 38-00666 to 38-06042
*A
Power up requirements added to Maximum Ratings Information
Document #: 38-06042 Rev. *A
Page 19 of 19
相关型号:
CY7C027-20AXCT
Multi-Port SRAM, 32KX16, 20ns, CMOS, PQFP100, ROHS COMPLIANT, PLASTIC, MS-026, TQFP-100
CYPRESS
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