AT77C104B_技术文档

Features

• Thermal Sensitive Layer Over a 0.35 µm CMOS Array

• Image Zone: 0.4 x 11.6 mm

• Image Array: 8 × 232 = 1856 Pixels

• Pixel Pitch: 50 × 50 µm = 500 dpi Resolution

• On-chip 8-bit Analog to Digital Converter

• Serial Peripheral Interface (SPI) - 2 Modes:

– Fast Mode at 16 Mbps Max for Imaging

– Slow Mode at 200 kbps Max for Navigation and Control

• Die Size: 1.5 × 15 mm

FingerChip^®

Thermal

Fingerprint

Sweep Sensor,

Hardware

• Operating Voltage: 2.3 to 3.6V

• Operating Temperature Range: -40°C to 85°C

• Finger Sweeping Speed from 2 to 20 cm/Second

• Low Power: 4.5 mA (Image Acquisition), 1.5 mA (Navigation), <10 µA (Sleep Mode)

• Hard Protective Coating (>4 Million Sweeps)

• High Protection from Electrostatic Discharge

• Small Form Factor Packaging

Description

This document describes the specifications of Atmel’s AT77C104B fingerprint sensor

dedicated to PDA, cellular and smartphone applications. Based on FingerChip ther-

mal technology, the AT77C104B is a linear sensor that captures fingerprint images by

sweeping the finger over the sensing area. This product embeds true hardware-based

8-way navigation and click functions.

Based,

Navigation and

Click Function,

SPI Interface

Applications

•

Scrolling, Menu and Item Selection for PDAs, Cellular or Smartphone Applications

•

Cellular and Smartphones-based Security (Device Protection, Network and ISP

Access, E-commerce)

AT77C104B

•

Personal Digital Agenda (PDA) Access

User Authentication for Private and Confidential Data Access

Portable Fingerprint Acquisition

Chip-on-board Package

Sweep your finger

to make life easier

Actual size of sensor

5347B–BIOM–08/04

Table 1. Pin Description for Chip-on-board Package: AT77C104B-CB08V

Pin Number

Name

Type

Description

1

Not connected

2

Not connected

3

Not connected

4

Not connected

5

GNDD

GNDA

VDDD

VDDA

SCK

G

P

I

Digital ground supply

6

Analog ground supply - connect to GNDD

Digital power supply

7

8

Analog power supply - connect to V^DD

Serial Port Interface (SPI) clock

Reserved for the analog test, not connected

Master-out slave-in data

9

10

11

12

13

14

15

16

17

18

19

TESTA

MOSI

TPP

IO

I

P

O

I

Temperature stabilization power

Master-in slave-out data

MISO

SCANEN

SSS

Reserved for the scan test in factory, must be grounded

Slow SPI slave select (active low

Interrupt line to host (active low). Digital test pin

Fast SPI slave select (active low)

Reset and sleep mode control (active high)

Front plane, must be grounded

I

IRQ

O

I

FSS

RST

I

FPL

I

Note:

The die attach is connected to pin 6 and must be grounded. The FPL pin must also be grounded.

2

AT77C104B

5347B–BIOM–08/04

AT77C104B

Figure 1. Typical Application

VDDD VDDD

10 kΩ

TESTA

VDDD

NC

IRQ

TPP

MISO

MOSI

SCK

VDDD

F

10µ

GNDD

VDDA

SSS

FSS

10µF

SCANEN

GNDA

FPL

GND

RST

The pull-up must be implemented for the master controller. The noise should be lower

than 30 mV peak to peak on VDDA.

Figure 2. Pin Description

NC

1

2

NC

3

NC

4

GNDD

GNDA

VDDD

VDDA

SCK

5

6

7

8

9

TESTA

MOSI

TPP

MISO

SCANEN

SSS

IRQ

FSS

RST

FPL

10

11

12

13

14

15

16

17

18

19

The TESTA pin is only used for testing and debugging. The SCANEN pin is not used in

the final application and must be connected to ground.

Warning : SSS and FSS must never be low at the same time. When both SSS and FSS

equal 0, the chip switches to scan test mode. With the SPI protocol, this

configuration is not possible as only one slave at a time can be selected.

However, this configuration works when debugging the system.

3

5347B–BIOM–08/04

Specifications

Table 2. Absolute Maximum Ratings

Parameter

Symbol

Comments

Value

Power supply voltage

Front plane

VDDD, VDDA

FPL

-0.5 to 4.6V

Note: Stresses beyond those listed

under “Absolute Maximum

GND to V_DD+0.5V

Ratings” may cause permanent

damage to the device. These are

stress ratings only and functional

operation of the device at these or

any other conditions beyond those

indicated in the operational

sections of this specification is not

implied. Exposure to absolute

maximum rating conditions for

extended periods may affect device

reliability.

SSS, FSS,

SCK, MOSI

Digital input

GND to V_DD+0.5V

Temperature stabilization

power

TPP

Tstg

GND to V_DD+0.5V

Storage temperature

-50 to +100°C

Lead temperature

(soldering 10 seconds)

Tleads

Do not solder

Forbidden

Table 3. Recommended Conditions of Use

Parameter

Symbol

Comments

Min

Typ

Max

Unit

2.5 5%

2.5

3.3

Positive supply voltage

V_DD

2.3

3.6

V

3.3 10%

Front plane

FPL

Must be grounded

GND

CMOS levels

20

V

Digital input voltage

Digital output voltage

Digital load

V

C_L

50

60

pF

°C

mA

Operating temperature range

Maximum current on TPP

T_amb

ITPP

Domestic "D" grade

-40 to +85

-

Use of TPP is optional

0

Table 4. Resistance

Parameter

Min Value

Standard Method

ESD

On pins HBM (Human Body Model) CMOS I/O

On die surface (zap gun) air discharge

Mechanical Abrasion

2 kV

MIL-STD-883 method 3015.7

NF EN 6100-4-2

16 kV

Number of cycles without lubricant

200 000

4 hours

MIL E 12397B

Multiply by a factor of 20 for correlation with a real finger

Chemical Resistance

Cleaning agent, acid, grease, alcohol, diluted acetone

Internal method

4

AT77C104B

5347B–BIOM–08/04

AT77C104B

Table 5. Explanation of Test Levels

Level Description

I

100% production tested at +25°C

II

100% production tested at +25°C, and sample tested at specified temperatures (AC testing done on sample)

Sample tested only

III

IV

V

VI

D

Parameter is guaranteed by design and/or characterization testing

Parameter is a typical value only

100% production tested at temperature extremes

100% probe tested on wafer at T_amb= +25°C

Table 6. Specifications

Parameter

Symbol

Test Level

Min

Typ

50

Max

Unit

Micron

Pixel

Resolution

IV

I

Size

8 × 232

Yield: number of bad pixels

Equivalent resistance on TPP pin

5

Bad pixels

Ohm

I

23

35

47

Power Consumption and DC Characteristics

The following characteristics are applicable to the operating temperature -40° C ≤Ta ≤+85°C.

Typical conditions are: power supply = 3.3V; T_amb= 25°C; F_SCK= 12 MHz (1600 slices per second); duty cycle = 50%

_LOAD120 pF on digital outputs unless otherwise specified.

C

Table 7. Power Requirements

Name

V_DD

Parameter

Conditions

Test Level

Min

2.3

3

Typ

2.5/3.3

4.5

Max

3.6

6

Unit-

V

Positive supply voltage

I

I_DD

Current on V_DDin acquisition mode

Current on V_DDin navigation mode

Current on V_DDin click mode

Current on V_DDin sleep mode

Current on V_DDin stand-by mode

mA

µA

I_DDNAV

I_DDCLI

I_DDSLP

I_DDSTB

1

1.5

2

0.2

0.3

0.5

10

Refer to “Power Management” on page 29

Table 8. Digital Inputs

Logic Compatibility

CMOS

Name

Parameter

Conditions

Test Level

Min

Typ

Max

Unit

Low level input current without pull-

up device⁽¹⁾

I_IL

V_I= 0V

I

1

µA

High level input current without

pull-down device⁽¹⁾

I_IH

V_I= V_DD

I

1

µA

5

5347B–BIOM–08/04

Table 8. Digital Inputs

Logic Compatibility

CMOS

Tri-state output leakage without

I_IOZ

V_I= 0V or V_DD

IV

1

µA

pull-up/down device⁽¹⁾

Low level input voltage⁽¹⁾

High level input voltage⁽¹⁾

(1)

V_IL

V_IH

I

0.3 V_DD

V

(1)

0.7 V_DD

V_DD= 3.3V

Temp = 25° C

V_HYST

Schmitt trigger hysteresis⁽¹⁾

IV

0.400

0.750

V

Table 9. Digital Outputs

Logic Compatibility

CMOS

Min

Name

Parameter

Conditions

Test Level

Typ

Max

Unit

I

_OL= 3 mA

V_DD= 3.3V 10%

0.15 V_DD

V_OL

Low level output voltage

I

V

(1)

I_OL= 1.75 mA

V_DD= 2.5V 5%

I

_OH= -3 mA

V_DD= 3.3V 10%

V_OH

High level output voltage

I

0.85 V_DD

V

I_OH= -1.75 mA

V_DD= 2.5V 5%

Note:

1. A minimum noise margin of 0.05 V_DDshould be taken for Schmitt trigger input threshold switching levels compared to V_IL

and V_IHvalues.

6

AT77C104B

5347B–BIOM–08/04

AT77C104B

Switching Performances

The following characteristics are applicable to the operating temperature -40° C ≤Ta ≤+85°C.

Typical conditions are: nominal value; T_amb= 25°C; F_SCK= 12 MHz; duty cycle = 50%; C_LOAD120 pF in digital output unless

specified otherwise.

Table 10. Timings

Parameter

Symbol

Test Level

Min

Typ

Max

Unit

Clock frequency acquisition

mode

F_ACQ

IV

8

16

MHz

Clock frequency navigation

mode and chip control

F_CTRL

I

-

0.2

80

MHz

Duty cycle (clock SCK)

Reset setup time

DC

IV

I

20

50

%

ns

(1)

T_RSTSU

T_SSSU

T_SSHD

½ T_SCK

Slave select setup time

Slave select hold time

I

Note:

1. T_SCK= 1/F_CTRL(clock period)

Table 11. 3.3V 10% Power Supply

Parameter

Symbol

T_SU

Test Level

Min

Typ

3

Max

Unit

ns

Data in setup time

IV

I

Data in hold time

T_H

1

ns

Data out valid

T_V

30

3

ns

Data out disable time from SS

high

T_DIS

T_IRQ

IV

3.8

ns

µs

IRQ hold time

Note:

All power supplies = +3.3V

Table 12. 2.5V 5% Power Supply

Parameter

Symbol

T_SU

Test Level

Min

Typ

3

Max

Unit

ns

Data in setup time

Data in hold time

IV

I

T_H

1

ns

Data out valid

T_V

30

3

ns

Data out disable time from SS

high

T_DIS

T_IRQ

IV

3.8

ns

µs

IRQ hold time

Note:

All power supplies = +2.5V

7

5347B–BIOM–08/04

Timing Diagrams: Slow and Fast SPI Interface

Figure 3. Read Timing Fast SPI Slave Mode

RST

SS

Trstsu

Tsssu

DC

Tsshd

SCK

Tdis

Tv

MISO

Figure 4. Read/Write Timing Slow SPI Slave Mode

SS

Tsssu

Tsshd

SCK

Tsu

Th

MOSI

MISO

Figure 5. Read Status Register to Release IRQ

SS

SCK

1

0

X

MOSI

IRQ

Tirq

Figure 6. Chip Initialization

RST

SS

Min = 10 µs

Trstsu

SCK

MISO

8

AT77C104B

5347B–BIOM–08/04

AT77C104B

Functional Description

The AT77C104B is a fingerprint sensor based on FingerChip technology. It is controlled

by an SPI serial interface through which output data is also transferred (a slow SPI for

the pointing function and a fast one for acquisition). Six modes are implemented:

–

Sleep mode: a very low consumption mode controlled by the reset pin RST.

In this mode, the internal clocks are disabled and the registers are initialized.

–

Stand-by mode: also a low consumption mode that waits for an action from

the host. The slow serial port interface (SSPI) and control blocks are

activated. In this mode the oscillator can remain active.

–

Click mode: waits for a finger on the sensor. The SSPI and control blocks

are activated. The local oscillator, the click array and the click block are all

activated.

Navigation mode: calculates the finger’s x and y movements across the

sensor. The SSPI and control blocks are still activated. The local oscillator,

the navigation array and the navigation block are also activated.

Acquisition mode: slices are sent to the host for finger reconstruction and

identification. The SSPI and control blocks are still activated. The fast serial

port interface block (FSPI) and the acquisition array are activated, as well as

the local oscillator when watchdog is required.

–

Test: this mode is reserved for factory testing.

In the final application, three main modes are used:

–

Stand-by: low consumption mode

Pointing: equivalent to click and navigation modes

Acquisition: fingerprint image capture

Note:

The term "host" describes the processor (controller, DSP...) linked to the sensor. It is the

master. In the description of n-bit registers (see “Function Registers” on page 11), the

term "b0" describes the Least Significant Bit (LSB). The term “b(n-1)” describes the Most

Significant Bit (MSB). Binary data is written as 0b_ and hexadecimal data as 0x_.

9

5347B–BIOM–08/04

Sensor and Block Diagram

Figure 7. Functional Block Diagram

TPP

FPL

VDDA

GNDA

VDDD

GNDD

RST

FSS

SCK

Fast Serial

Interface

SPI

Acquisition

(8-16 MHz)

Pixel Array

(232 x 8)

Array

CTRL

Navigation

Algorithms

MISO

Slow Serial

Interface

SPI

(200 kHz)

+

Oscillator (420 kHz)

MOSI

SSS

Click

Algorithm

Click

CTRL

Click Pixels

(12)

Control

Register

IRQ

Watchdog

Heating

SCANEN

TESTA

Test

The circuit is divided into the following main sections:

•

An array or frame of 8 x 232 pixels + 1 dummy column

An analog to digital converter

An on-chip oscillator

Control and status registers

Navigation and click units

Slow and fast serial interfaces

10

AT77C104B

5347B–BIOM–08/04

AT77C104B

Function Registers

Table 13. Registers

Register

Address (b3 down to b0)

Read/Write

Read

STATUS

0000

0001

0010

0011

0100

0101

0110

0111

1000

1001

1010

1011

1100

1101

1110

MODECTRL

ENCTRL

Read/Write

Reserved

Read

HEATCTRL

NAVCTRL

CLICKCTRL

MOVCTRL

NAVIGATION⁽¹⁾

PIXELCLICK

Reserved

Note:

1. Navigation requires 3 registers. The reading of the first register (0b1000) enables the

reading of all 3 registers.

11

5347B–BIOM–08/04

Status Register

Register Name:Status (8 bits)

Access Type:Read Only

Function:State of AT77C104B

b7

CLICK

0

b6

MOV

0

b5

TRANSIT

0

b4

SLICE

0

b3

READERR

0

b2

–

b1

–

b0

–

0

•

CLICK: click detection

0: default

1: click detected

MOV: movement detection

0: default

1: X or Y movement detected

•

TRANSIT: not used, for testing only

SLICE: not used, for testing only

READERR: read error detection

0: default, no error

1: read error detected

Note:

To clear the interrupts, the status register is initialized after each reading from the host.

12

AT77C104B

5347B–BIOM–08/04

AT77C104B

Modectrl Register

Register Name:Modectrl (7 bits)

Access Type:Read/Write

Function:Mode control

b6

b5

MODE

0

b4

MODE

0

b3

b2

b1

–

b0

–

MODE (MSB)

0

MODE (LSB)

0

ANALOGRST

1

0

•

MODE: select operating mode

0000: standby

0001: test (reserved for factory use)

0010: click

0100: navigation

1000: acquisition

Certain changes can be made. For example, MODE can be set to 0b0110 to activate

click and navigation.

•

ANALOGRST: reset local oscillator

0: oscillator in active mode

1: oscillator in power-down mode

Notes: 1. Click or navigation modes cannot be used when the local oscillator is switched off. .

2. To return to standby mode and stop the oscillator (to save on power consumption),

two Modectrl register accesses are

necessary: the first one to select standby mode and the second to switch off the

oscillator.

3. The read-only registers cannot be read when the oscillator is turned off.

4. To shift between navigation and acquisition modes, you must be in standby mode

(Modectrl = 0b00001).

If modes such as “acquisition and click” or “acquisition and navigation” are programmed

together, they will be ignored by the system.

Programmed Mode

Register Value

01xx

11xx

1x1x

0x1x

With x = 0 or 1.

13

5347B–BIOM–08/04

Enctrl Register

Register Name:Enctrl (7 bits)

Access Type:Read/Write

Function:Interrupts control

b6

CLICKEN

0

b5

MOVEN

0

b4

b3

SLICEN

0

b2

b1

–

b0

–

TRANSITEN

0

READERREN

0

•

CLICKEN: click interrupts enable

0: default

1: click IRQ enabled

IRQ is generated when a click is detected.

•

MOVEN: movement interrupts enable

0: default

1: movement IRQ enabled

IRQ is generated when an X or Y movement is detected.

•

TRANSITEN: not used, for testing only

SLICEN: not used, for testing only

READERREN: read error interrupts enable

0: default

1: read error IRQ enabled

IRQ is generated when a read error is detected.

Note: The interrupt is cleared after the status register is read.

Heatctrl Register

Register Name:Heatctrl (7 bits)

Access Type:Read/Write

Function:Heating control

b6

HEAT

0

b5

WDOGEN

0

b4

b3

b2

–

b1

–

b0

–

HEATV (MSB)

0

HEATV(LSB)

0

•

HEAT: sensor heating

0: default, no heating

1: heating

The default value is recommended to optimize power consumption.

•

WDOGEN: watchdog enable

0: default

1: watchdog enabled

Watchdog automatically stops heating of the sensor after a time-out.

14

AT77C104B

5347B–BIOM–08/04

AT77C104B

•

HEATV (2 bits): heating power value

00: 50 mW

01: 100 mW

10: reserved

11: reserved

V

_DDis between 2.6 and 3.6V.

Notes: 1. Heating can only be used in the acquisition mode (it is not allowed in navigation or

click modes).

2. The oscillator has to be activated when the watchdog is required and must not be

stopped while the watchdog remains active.

Navctrl Register

Register Name:Navctrl (7 bits)

Access Type:Read/Write

Function:Navigation control

b6

b5

b4

b3

NAVV (LSB)

0

b2

b1

b0

reserved

0

NAVFREQ

(MSB)

NAVFREQ (LSB)

0

NAVV ( MSB)

0

CLICKV (MSB)

0

CLICKV (LSB)

0

1

•

NAVFREQ: navigation frequency

00: 5.8 kHz

01: 2.9 kHz (default value)

10: 1.9 kHz

11: 1.5 kHz

A faster frequency enables faster finger movement detection. A lower frequency

enhances sensitivity. Refer to notes 1 and 2 on page 16.

•

NAVV: navigation pixels threshold

00: lower threshold

01:

10:

11: higher threshold

Sets the minimum analog value detected as a high level (‘1’). Refer to note 1 on page

16.

•

CLICKV: click pixels threshold

00: lower threshold

01:

10: higher threshold

11: reserved

Sets the minimum analog value detected as a high level (‘1’) and the maximum analog

value detected as a low level (‘0’). See note 3.

15

5347B–BIOM–08/04

Notes: 1. Navfreq and Navv registers should not be changed once the navigation mode is

selected. Finger sensitivity refers to the minimum level of information required from a

finger. The sensitivity is linked to the integration time; a longer integration time

enables better sensitivity but does not tolerate fast movement.

2. The navigation frequency is the frequency needed for the reading of one new naviga-

tion frame.

3. The Clickv register should not be changed once the click mode is selected.

Clickctrl Register

Register Name:Clickctrl (7 bits)

Access Type:Read/Write

Function:Click control

b6

b5

b4

b3

b2

b1

b0

CLICKFREQ

(MSB)

CLICKFREQ

(LSB)

CLICKDET

(MSB)

CLICKDET

(LSB)

CLICKCPT

(MSB)

CLICKCPT

(LSB)

0

1

0

1

0

1

•

CLICKFREQ: click pixels reading frequency

00: 180 Hz

01: 90 Hz (default value)

10: 60 Hz

11: 45 Hz

Faster frequency enables faster finger click detection. Lower frequency enables higher

sensitivity.

•

CLICKDET: threshold for selecting the black/white color of a slice

00: more than 7 black/white pixels and less than 5 white/black pixels

01: more than 8 black/white pixels and less than 4 white/black pixels

10: more than 9 black/white pixels and less than 3 white/black pixels

11: more than 10 black/white pixels and less than 2 white/black pixels

•

CLICKCPT: click detection counter (maximum number of slices read between

two transitions)

000: 5

001: 7

010: 10

011: 12

100: 16

101: 20

110: 25

111: 31

Two transitions are interpreted as a click if the number of slices between them is less

than CLICKCPT. This is used to differentiate a touch-down/touch-up from a real click. A

click is equivalent to two close touch-down/touch-up transitions.

16

AT77C104B

5347B–BIOM–08/04

AT77C104B

This register adjusts the “time out” for considering the two transitions as a click.

Note: Clickfreq and Clickcpt registers should not be changed once the click mode is selected.

Movectrl Register

Register Name:Movctrl (7 bits)

Access Type:Read/Write

Function:In stream mode, during navigation calculation, the AT77C104B must

interrupt the host when a maximum absolute X or Y movement is detected (second and

third navigation registers). The MOVECTRL register enables you to control this value.

This value can be set as the minimum finger movement value at which the pointing

device makes a displacement.

b6

(MSB)

0

b5

–

b4

–

b3

–

b2

–

b1

–

b0

(LSB)

0

•

MOVCTRL: generates an interrupt when the second or third navigation

register (X or Y absolute movement) is greater than the value programmed in

the Movectrl register

0b0000000

0b0000001

0b0000010

...

0b1111111

For example, when MOVCTRL = 0b0001001, an interruption to the host is generated

when the absolute X movement register (second navigation register) or absolute Y

movement register (third navigation register) is greater than 0b00010010.

Note:

The Movctrl register should not be changed once the navigation mode is selected.

17

5347B–BIOM–08/04

Navigation Register

Register Name:Navigation (3 x 8 bits)

Access Type:Read Only (these three registers cannot be read individually . The read-

ing command of the first navigation register [address 0b1000] returns the value of the

three registers).

Function:The format of the navigation registers is similar to the PS/2 protocol. Three

registers are used to codemovements and clicks. The navigation registers are initialized

after each reading. The registers only represent actions (movement, click, transition...)

that have occurred since the last data packet sent to thehost.

General Register

b7

YOVR

0

b6

XOVR

0

b5

YSIGN

0

b4

XSIGN

0

b3

1

b2

TRANS

0

b1

CLICK

0

b0

FINGER

0

1

•

YOVR: Y overflow

0: default

1: Y movement overflow

High (‘1’) when the Y movement counter is overflowed.

•

XOVR: X overflow

0: default

1: X movement overflow

High (‘1’) when the X movement counter is overflowed.

•

YSIGN: Y sign bit

0: default, positive Y movement

1: negative Y movement

High (‘1’) when the Y movement is negative. Low when the Y movement is positive.

•

XSIGN: X sign bit

0: default, positive X movement

1: negative X movement

High (‘1’) when the X movement is negative. Low when the X movement is positive.

•

TRANS: not used, for test purposes only.

CLICK: Click

0: default

1: click detected

This function is not in the PS/2 protocol.

•

FINGER: not used, for test purposes only.

18

AT77C104B

5347B–BIOM–08/04

AT77C104B

Note:

In the PS/2 protocol, bits b2 and b1 are used to code the middle and right buttons

respectively, and b3 is set to high.

Absolute X Movement Register (0 to 255 Pixels)

b7

b6

–

b5

–

b4

–

b3

–

b2

–

b1

–

b0

XMOV (MSB)

0

XMOV (LSB)

0

Absolute Y Movement Register (0 to 255 Pixels)

b7

b6

–

b5

–

b4

–

b3

–

b2

–

b1

–

b0

YMOV (MSB)

0

YMOV (LSB)

0

Note:

When a click is detected, the information is placed in the b7 bit of the status register and

in the b1 bit of the general navigation register. The reading of the status register initial-

izes the b7 bit but does not initialize the b1 bit of the general navigation register. The host

must carefully correlate the two bits.

19

5347B–BIOM–08/04

SPI Interface General Description

Two communication busses are implemented in the device:

•

The control interface, a slow bus that controls and reads the internal registers

(status, navigation, control...).

•

The pixels’ acquisition interface, a fast bus that enables full pixel acquisition by the

host.

A synchronous Serial Port Interface (SPI) has been adopted for the two communication

busses.

The SPI protocol is a slave/master full duplex synchronous serial communication. This

protocol uses three communication signals:

•

SCK (Serial Clock): the communication clock

MOSI (Master Out Slave In): the data line from the master to the slave

MISO (Master In Slave Out): the data line from the slave to the master

The slaves are selected by an input pin SS/ (Slave Select). A master can communicate

with several slaves.

The word length of the transferred data is fixed to 8 bits. The Most Significant Bit (MSB)

is sent first. For each 8-bit transfer, 8 bits are sent from the master to the slave and 8

bits transferred from the slave to the master. Transfers are still synchronized with the

communication clock (SCK). Only the host can initialize transfers. To send data, the

slave must wait for an access from the master. When there is no transfer, a clock is not

generated.

Figure 8. One Master with Several Slaves

SS/3

Slave #3

SS/1

Slave #1

SS/2

Slave #2

Master

SCK

MISO

MOSI

When a master is connected with several slaves, the signals SCK, MISO and MOSI are

interconnected. Each slave SS/ is driven separately. Only one slave can be selected,

the others have their MISO tri-stated and ignore MOSI data.

The SS/ signal falls a half-period before the first clock edge, and rises a half-period after

the last clock edge.

Clock Phase and Polarity During phase zero of the operation, the output data changes on the clock’s falling edge

and the input data is shifted in on the clock’s rising edge. In phase one of the operation,

the output data changes on the clock’s rising edge and is shifted in on the clock’s falling

edge.

20

AT77C104B

5347B–BIOM–08/04

AT77C104B

Polarity configures the clock’s idle level, which is high ('1') during polarity one of the

operation and low ('0') during polarity zero of the operation.

AT77C104B and the SPI

The AT77C104B is always the slave and the host always the master. The host drives

the SCK clock. Both the AT77C104B and the host transmit data with the MISO signal.

The word length of the transferred data is fixed to 8 bits. The Most Significant Bit (MSB)

is sent first.

The AT77C104B supports only one phase and polarity configuration:

•

The clock’s idle level set to high (polarity 1)

The output data changed on the clock’s falling edge, and input data shifted in on the

clock’s rising edge (phase 0).

Figure 9. SPI Waveform (Phase = 0, Polarity = 1)

SCK

LSB

MSB

MOSI/MISO

SS/

Emission

Reception

Note:

During initialization of the SCK wire (power-on or reset), SS/ has to be inactive (‘1’).

Recommendations

The SSS or FSS falling edge should be half a clock cycle before the first SCK falling

edge and the SSS or FSS rising edge should be half a clock cycle after the last SCK

rising edge.

SPI Behavior with

Hazardous Access

The control register block uses an internal finite state machine that can only be initial-

ized by the RST pin (asynchronous reset). When SPI access does not use 8 clock

pulses, the internal finite state machine is desynchronized. The only way to resynchro-

nize it is by resetting the sensor with the RST pin. No requester modification is recorded

when a write access is made on a read-only register. Reliable initialization of read-only

registers is not guaranteed when the slow SPI’s maximum clock frequency is not

respected.

21

5347B–BIOM–08/04

Control Interface (Slow SPI)

This interface controls the sensor’s internal registers. The protocol enables reading and

writing of these registers.

The master (host) initiates transfers to the slave (sensor). The sensor can only use its

interrupt pin to communicate with the host. When the host is interrupted, it must read the

status register before continuing operation.

The word length of the transferred data is fixed to 8 bits. The Most Significant Bit (MSB)

is sent first.

Communication Protocol Accesses to the host are structured in packets of words. The first word is the command

and the other words are the data.

The b7 bit is used to differentiate the command and data. When the word is a command,

b7 is high ('1') and when the word is a piece of data, b7 is low ('0').

The following protocol is used:

Command Format

The host indicates to the sensor if it wants to read or write into a register and indicates

the register’s address.

b7

1

b6

b5

b4

b3

b2

b1

x

b0

x

Read

(1)/Write (0)

Address (b3)

Address (b2)

Address (b1)

Address (b0)

Data Format (Writing into

If writing into a register, the host transmits the data.

Register)

b7

0

b6

b5

b4

b3

b2

b1

b0

Data (b6)

Data (b5)

Data (b4)

Data (b3)

Data (b2)

Data (b1)

Data (b0)

Data Format (Reading of

Register)

If reading a register, the host transmits one or several packets of data and data is shifted

in from the sensor. The host transmits dummy words with the data format (b7 is low

['0’]). If reading the navigation or pixelclick registers, the host transmits three packets of

data to read the three registers.

b7

0

b6

x

b5

x

b4

x

b3

x

b2

x

b1

x

b0

x

Note:

The host cannot communicate with the sensor without receiving data from it. Useless data is ignored by the host.

22

AT77C104B

5347B–BIOM–08/04

AT77C104B

Communication Speed

To reduce consumption, the control interface’s communication speed is set to the lowest

possible speed and depends on the host’s configuration.

To communicate with “fast” controllers, the sensor’s communication speed can be set to

200 kbits/s.

Example for the MODECTRL

Register

Figure 10 represents a typical writing sequence into an internal register (MODECTRL

register in this example).

See Appendix B for flowchart.

Figure 10. Writing into an Internal Register

SSS

SCK

MOSI

0

x

0

x

1

x

1

x

0

x

0

x

0

x

0

x

1

x

0

x

0

x

0

x

0

x

1

x

MISO

Writing into MODECTRL Register Requested

New Data to be Written into MODECTRL Register

(Navigation and Click Mode)

Note:

The break on SCK on the SPI chronogram has been added for better comprehension only. In a real application, SCK can be

continuous.

Figure 11 represents a typical reading sequence of a register different from the naviga-

tion register. In this example, the status register is used.

Figure 11. Reading Sequence of a Register (Except for Navigation Registers)

SCK

MOSI

0

1

x

1

x

1

x

0

x

0

x

0

x

0

x

MISO

0

Reading of STATUS Register Requested

Emission of the STATUS Register

(Click Detected)

23

5347B–BIOM–08/04

Example of Navigation

Registers

Figure 12 represents a typical reading sequence of the three navigation registers.

Refer to “Appendix C” on page 34 for flowchart

Figure 12. Reading of the Navigation Registers

SCK

MOSI

1

0

X

0

X

1

X

0

X

1

X

0

X

1

0

X

0

X

0

X

1

X

1

X

0

X

0

X

0

X

0

X

0

X

1

X

0

X

0

X

0

X

0

X

0

1

MISO

X

Emission of the First

Navigation Register

(No Overflow, Y Negative Movement

Click Detected, Black Slice)

Emission of the Second

Navigation Register

(X Absolute Movement

= 24 Pixels)

Emission of the Third

Navigation Register

(Y Absolute Movement

= 144 Pixels)

Reading of Navigation

Register Requested

Image Capture (Fast SPI)

This serial interface enables full-speed acquisition of the sensor’s pixels by the host.

This interface only supports the serial clock (SCK) and one data line: MISO (Master In/

Slave Out).

Communication Protocol When the sensor is in acquisition mode, the host can receive pixels through the fast SPI

(FSS/ = 0). The host must transmit the communication clock (SCK) to receive the pixels.

This clock must have a regular frequency to obtain constant fingerprint slices (See “Reg-

istration Integration Time” on page 27).

With the sensor configured to acquisition mode, the controller can proceed to fast

accesses.

Figure 13. Example of an 8-bit Access

Controller

FSS/ = 0

Sensor

Sending of Dummy Data

0b0000000

Sending of 2 Pixels (8 Bits)

Reception of 2 Pixels

End of

Communication

?

No

Yes

FSS/ = 1

During an 8-bit access, the sensor transmits two pixels (each pixel is coded on 4 bits).

24

AT77C104B

5347B–BIOM–08/04

AT77C104B

Figure 14. Fast SPI Communication

SCK (Pixel Clock)

MISO

Bit3

MSB

Bit3

MSB

Bit2

Bit0 Bit3 Bit2 Bit1

Pixel 2i - 1

Bit0

Bit2

Bit1 Bit0

Bit1

Bit3 Bit2 Bit1 Bit0

Pixel 2i + 1

Pixel 2i

Pixel 2i + 2

Transmission Clock

Edge (Sensor)

Reception Clock

Edge (Host)

Communication Speed

The acquisition speed of the pixels is linked to the clock’s communication speed. The

faster the communication clock, the faster the authorized maximum finger sweeping

speed. The sensor supports fast communications up to 16 Mbps.

Reading of Frame

A frame consists of 232 true columns and 1 dummy column of 8 pixels of 4 bits each. A

frame starts with a dummy column.

Figure 15. Example of a Frame

Dummy

Column

232 x 8 Pixels Column

p1

p2

p3

p4

p5

p6

p7

p8

P9

0

F

0

F

2

0

p10

p11

P12

P13

P14

Synchro = F0F00200

Pixel Frame

P15

p16

0

The first dummy column, at the beginning of the pixel array, is added to the sensor to act

as a specific easy-to-detect pattern, and represents the start of the frame tag.

The pixel array is always read in the following order: the first byte, following the 4 bytes

of the dummy column, which contains the value of the pixels physically located on the

upper left corner of the array, when looking at the die with bond pads to the right. Then

another 4 bytes are read that contain the value of the pixels located in the same column

from top to bottom. The next column on the right is output, and so on, until the last line

on the right, close to the bond pads, is output.

Even values are first sent during the data serialization for SPI transfer. Therefore, the

synchronization sequence on the chip’s MISO output is F0F00200.

25

5347B–BIOM–08/04

Figure 16. Reading of Frame

SCK

MISO

F

0

F

0

2

0

P2

P1

P4

P3

P6

P5

P8

P7

P10 P9

Dummy Column

Second Pixel

Column

First Pixel

Column

Notes: 1. For the first array or frame reading, 40 dummy clock cycles must be sent before the first data arrives. This is necessary for

the initialization of the chip pipeline. Consequently, the first synchronization sequences appear after 40 clock cycles. For the

following array readings, data arrives at each clock cycle. One should implement a synchronization routine in the protocol to

look for the F0F00200 pattern.

2. The Most Significant Bit (MSB) is sent first.

Reading of Entire Image The FingerChip delivers fingerprint slices or frames with a height of 0.4 mm and a width

of 11.6 mm (this equals 8 × 232 pixels). Pixels are sampled/read sequentially and are

synchronous with SCK. Raw slices are captured by the acquisition system and over-

lapped with the corresponding X or Y finger displacement computed by Atmel

reconstruction software. This reconstruction software supports a sweeping speed from 2

to 20 cm/s.

The table below shows finger speeds according to the different clock frequencies. The

reconstruction results are obtained after acquisition of all slices.

Table 14. Finger Speeds Versus Clock Frequencies

Absolute

Fsck

(MHz)

Data Rate

(Mbit/s)

Slice Rate

(Slices/s)

MaximumFinger

Speed (cm/s)

Comments

Too slow

1

134

3

2

268

6

Too slow

4

536

12

18

24

36

48

Minimum

6

804

Normal speed

Good speed

Very good speed

8

1072

1608

2146

12

16

12

16

26

AT77C104B

5347B–BIOM–08/04

AT77C104B

Registration Integration

Time

The pixel’s integration time (the time needed for one frame reading) must be as regular

as possible to obtain consistent fingerprint slices. This time is directly dependant on the

SCK, SPI clock and frequency. Therefore, the SPI cycle of 4 × 8 × 233 clock pulses

should be as regular as possible.

Figure 17. Regular Integration Time

Regular Integration Time

Frame n

Frame n+1

Frame n+2

Frame n+3

Clock SCK

500 us max

4 x 8 x 233 =

7456 Pulses

7456 pulses

7456 Pulses

233 = 232 + 1 Dummy Column

Note:

The 500 µs duration corresponds to the host’s computation time (slice reconstruction, finger detection…) and in the illustration is

given as an example only. Once the host detects a finger, this value remains constant, thus guaranteeing a regular integration

time.

Navigation (Slow SPI)

The sensor’s navigation function includes the processing elements necessary for pro-

viding the displacement of the finger touching the sensor in an up or down and right or

left direction. It is aimed at a screen menu navigation or simple pointing application. In

addition, a click processing function is embedded to detect a quick touch of the finger on

the sensor. It is aimed at screen text, box or object selection. A double-click function

could also be implemented in the software.

This interface has been designed to resemble the PS/2 mouse protocol.

An interrupt signal IRQ indicates to the host that an action has been detected. The host

must read the status register to obtain details on the action. The IRQ signal enables

implementation of an efficient power consumption protocol.

Note:

•

Click and navigation modes can be used together.

Two configurations are implemented for the click and navigation modes:

–

Stream mode, where the sensor sends an interrupt to the host when a

movement or a change in the button’s state is detected.

–

Remote mode, where the sensor does not interrupt the host but waits for its

registers to be read.

In these two modes, the registers are initialized after each reading from the host.

See “Appendix D” on page 35 for an example of an interrupt generated by a movement

detection.

27

5347B–BIOM–08/04

Navigation

See “Navigation Register” on page 18

The typical navigation slice frequency has been fixed to 2.9 kHz. A programmable

divider is implemented in the control registers (NAVFREQ) to reduce this frequency.

Finger displacement is provided as a number of pixels in X and Y directions. Negative

movements are possible. The register is cleared after the navigation registers are read.

These registers are incremented or decremented between two accesses.

Table 15.

Navctrl

Register

Typical Navigation

Slice Frequency

(kHz)

Typical

Integration Time

(µs)

Typical Maximum

Finger Speed

(cm/s)

(Bits b6 to b5)

00

01

10

11

5.8

2.9

1.9

1.5

172

345

526

666

30

15

9.5

7.5

Click

See “Clickctrl Register” on page 16

The sensor generates a click detection. The host must read the b7 bit of the status reg-

ister or the b1 bit of the general navigation register.

The click function is composed of an array of a few pixels and a processing unit. The

typical click slice frequency is 90 Hz. A programmable divider is implemented to modify

this frequency in the control registers (CLICKFREQ).

Double-click

This function is performed by the controller, allowing better flexibility. It detects a suc-

cession of two clicks.

Temperature Stabilization Function and Watchdog

The sensor has an embedded temperature stabilization unit that identifies a difference

in temperature between the finger and the sensor. When this difference is increased, the

images are more contrasted. This function is optional and its use depends on the quality

of the image processing software, therefore its management should be decided together

with the image processing software.

In order to limit excessive current consumption by the use of the temperature stabiliza-

tion function, a watchdog has been implanted in the sensor. The local oscillator stops

the heating of the module after a defined time. The oscillator should not be stopped as

long as watchdog is active, otherwise the clock stops automatically.

When heating of the sensor is requested '1' is written in bit 6 of the HEATCTRL

register) and the watchdog is enabled '1' is written in bit 5 of the HEATCTRL register),

the sensor is heated during ‘n’ seconds.

Due to the oscillator frequency dispersion, the value of n is:

2 seconds (minimum) < n = 4 seconds (typical) < 7 seconds (maximum).

The accuracy of n is not important since the heat register can be enabled successively.

The level of power consumption is programmable. Two pre-programmed values are set

to 50 or 100 mW.

28

AT77C104B

5347B–BIOM–08/04

AT77C104B

The dissipated die power is quasi constant over a significant supply voltage range as

shown below (mode 50 mW selected):

Figure 18.

Power = f ( Vdd )

5,40E-02

5,30E-02

5,20E-02

5,10E-02

5,00E-02

4,90E-02

4,80E-02

2

2,2

2,4

2,6

2,8

3

3,2

3,4

3,6

3,8

VDD

Power = f ( Vdd)

Note:

This function is useless for navigation and click modes.

Power Management

Sleep Mode (<10 µA)

Reset high

Standby Mode

Power consumption can be reduced in several ways:

(<10 µA Providing SPI

Bus not Accessed)

•

By switching off the FingerChip sensor.

By programming a standby mode by writing 00001xx in the MODCTRL register

(STANDBY mode set and oscillator stopped.) Bit b6 (HEAT) of the HEATCTRL

register must be turned to ‘0’ when programming standby mode.

Acquisition Mode

Current Consumption

Static Current Consumption

When the SPI bus is not used, only the analog part of the circuit consumes power at

around 4 mA.

Dynamic Current

Consumption

When the clock is running, the digital sections also consume current. With a 30 pF load

at 16 MHz, the power consumption is approximately 4.5 mA on the V_DDpins.

29

5347B–BIOM–08/04

Navigation and Click

Modes Current

Consumption

Static Current Consumption

The SPI bus’ consumption is very low in click and navigation modes, the majority of the

consumption being generated by the analog part of the circuit. Therefore, the static and

dynamic consumption is almost the same.

Dynamic Current

Consumption

With a 30 pF load at maximum clock frequency, the current consumption in click mode is

almost 300 µA on pins V_DD. With a 30 pF load at maximum clock frequency, the current

consumption in navigation mode is approximately 1.5 mA.

Note:

We advise use of the interrupt capabilities (IRQ signal or Interrupts register) so as to limit

the host’s overall current consumption. The host can, from time to time, check the IRQ or

Interrupt register. A strategy for very low power consumption is to use the click mode only

as a wake-up. The click mode is only 300 µA, and once a click is detected the host can

turn on the navigation mode as well.

Packaging Mechanical Data

Figure 19. AT77C104B-CB08V Top View

4.8 max

+0.07

1.50 - 0.01

4.6 max

A

5

0.3

23 0.3

A

0.2

11.98

4.8 0.4

1.1 min

All dimensions in mm.

Figure 20. AT77C104B-CB08V Bottom View

0.5 0.08

2.25 0.3

19

1

All dimensions in mm.

30

AT77C104B

5347B–BIOM–08/04

AT77C104B

Package Information

Electrical Disturbances

Three areas of the FingerChip device must never be in contact with the casing, or any

other component, so as to avoid electrical disturbances. These areas are shown in Fig-

ure 21:

Figure 21. Sensitive Areas

6 mm

11.5 mm

Figure 22. Epoxy Overflow

Maximum epoxy overflow width: 0.35 mm on the die edge.

Maximum epoxy overflow thickness: 0.33 mm.

0.35

AA Section

Fingerchip

Epoxy Glue Overflow

Note:

Refer to Figure 19 on page 30.

Ordering Information

Package Device

_

104B

AT77C

CBXX

V

Atmel prefix

FingerChip family

Quality Level: Standard

Device type

Package

CB08: Chip On Board (COB)

Temperature range

V: -40˚ to +85˚C

31

5347B–BIOM–08/04

Appendix A

Controller Initialization

Host Controller

Initialization

no

Controller

Initialized ?

Yes

SPI Initialization

(Phase = 0, Polarity = 1)

no

SPI

Initialized

?

Yes

RST = 1

Sensor Initialization

Pulse

no

> 10 us ?

Yes

RST = 0

32

AT77C104B

5347B–BIOM–08/04

AT77C104B

Appendix B

Example for the

MODECTRL Register

Controller

Interrupts Masked

SSS/ = 0

Sensor

MODECTRL Reading

Requested

Sending 0b11000100

Reception of the Command

Reading of MODECTRL

No

Transfer

Ended ?

Yes

Modification of MODECTRL to

Change Mode Bits

Sending of MODECTRL

No

Transfer

Ended ?

Yes

Modification of MODECTRL to

Change Mode Bits

Reception of the Command

Writing of MODECTRL

MODECTRL Writing Requested

Sending of 0b10000100

Transfer

ended ?

No

Yes

Sending of the New

MODECTRL

Reception of MODECTRL

No

Transfer

ended ?

Yes

SSS/ = 1

Interrupts enabled

33

5347B–BIOM–08/04

Appendix C

Example of Navigation

Registers

Controller

Interrupts Masked

SSS/ = 0

Sensor

NAVIGATION Reading

Requested

Sending 0b11000000

Reception of the Command

Reading of NAVIGATION

No

Transfer

Ended ?

Yes

Sending of Dummy Data

0b00000000

Reception of NAVIG1

Sending of NAVIG1

Transfer

Ended ?

Yes

Sending of Dummy Data

0b00000000

Reception of NAVIG2

Sending of NAVIG2

Transfer

Ended ?

Yes

Sending of Dummy Data

0b00000000

Reception of NAVIG3

Sending of NAVIG3

Transfer

Ended ?

Yes

SSS/ = 1

Interrupts Enabled

34

AT77C104B

5347B–BIOM–08/04

AT77C104B

Appendix D

Example of an Interrupt

Generated by a

Controller

Movement Detection

Main Program

Sensor

Interrupt Generated

IRQ/ = 0

No

Interrup ?

Interrupts Masked

SSS/ = 0

STATUS Reading Requested

Sending of 0b11000000

Reception of the Command

No

Transfer

Ended ?

Yes

Sending of Dummy Data

0b00000000

Reception of STATUS

Sending of STATUS

Interrupts Cleared

No

Transfer

Ended ?

Yes

Interrupts Control

Detection of Movement

NAVIGATION Reading

Requested

Sending of 0b11100000

Reception of the Command

Reading of NAVIGATION

Transfer

Ended ?

No

Yes

Sending of Dummy Data

0b00000000

Reception of the 3 Navigations

Sending of the 3

Navigation Registers

No

3 Registers

Values Sent ?

Yes

SSS/ = 1

Interrupts enabled

35

5347B–BIOM–08/04

Atmel Corporation

Atmel Operations

2325 Orchard Parkway

San Jose, CA 95131, USA

Tel: 1(408) 441-0311

Fax: 1(408) 487-2600

Memory

RF/Automotive

Theresienstrasse 2

Postfach 3535

74025 Heilbronn, Germany

Tel: (49) 71-31-67-0

Fax: (49) 71-31-67-2340

2325 Orchard Parkway

San Jose, CA 95131, USA

Tel: 1(408) 441-0311

Fax: 1(408) 436-4314

Regional Headquarters

Microcontrollers

2325 Orchard Parkway

San Jose, CA 95131, USA

Tel: 1(408) 441-0311

Fax: 1(408) 436-4314

1150 East Cheyenne Mtn. Blvd.

Colorado Springs, CO 80906, USA

Tel: 1(719) 576-3300

Europe

Atmel Sarl

Route des Arsenaux 41

Case Postale 80

CH-1705 Fribourg

Switzerland

Tel: (41) 26-426-5555

Fax: (41) 26-426-5500

Fax: 1(719) 540-1759

Biometrics/Imaging/Hi-Rel MPU/

High Speed Converters/RF Datacom

Avenue de Rochepleine

La Chantrerie

BP 70602

44306 Nantes Cedex 3, France

Tel: (33) 2-40-18-18-18

Fax: (33) 2-40-18-19-60

BP 123

38521 Saint-Egreve Cedex, France

Tel: (33) 4-76-58-30-00

Fax: (33) 4-76-58-34-80

Asia

Room 1219

Chinachem Golden Plaza

77 Mody Road Tsimshatsui

East Kowloon

Hong Kong

Tel: (852) 2721-9778

Fax: (852) 2722-1369

ASIC/ASSP/Smart Cards

Zone Industrielle

13106 Rousset Cedex, France

Tel: (33) 4-42-53-60-00

Fax: (33) 4-42-53-60-01

1150 East Cheyenne Mtn. Blvd.

Colorado Springs, CO 80906, USA

Tel: 1(719) 576-3300

Japan

9F, Tonetsu Shinkawa Bldg.

1-24-8 Shinkawa

Chuo-ku, Tokyo 104-0033

Japan

Tel: (81) 3-3523-3551

Fax: (81) 3-3523-7581

Fax: 1(719) 540-1759

Scottish Enterprise Technology Park

Maxwell Building

East Kilbride G75 0QR, Scotland

Tel: (44) 1355-803-000

Fax: (44) 1355-242-743

Literature Requests

www.atmel.com/literature

Disclaimer: Atmel Corporation makes no warranty for the use of its products, other than those expressly contained in the Company’s standard

warranty which is detailed in Atmel’s Terms and Conditions located on the Company’s web site. The Company assumes no responsibility for any

errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and

does not make any commitment to update the information contained herein. No licenses to patents or other intellectual property of Atmel are

granted by the Company in connection with the sale of Atmel products, expressly or by implication. Atmel’s products are not authorized for use

as critical components in life support devices or systems.

poration or its subsidiaries. Other terms and product names may be the trademarks of others.

Printed on recycled paper.

5347B–BIOM–08/04


型号：	AT77C104B
厂家：	ATMEL
描述：	FingerChip Thermal Fingerprint Sweep Sensor, Hardware Based, Navigation and Click Function, SPI Interface 的FingerChip热指纹扫描传感器，基于硬件的导航和点击功能， SPI接口传感器
文件：	总36页 (文件大小：415K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

AT77C104B [ATMEL]

相关型号：

SI9130DB

SI9135LG-T1

SI9135LG-T1-E3

SI9135_11

SI9136_11

SI9130CG-T1-E3

SI9130LG-T1-E3

SI9130_11

SI9137

SI9137DB

SI9137LG

SI9122E