PIN LIST

Name

Pin

Type

Description

XTALIN

9

I

Crystal Input

XTALOUT

10

O

Crystal Output

RESET

12

I

Reset Function to initialise the device (active low)

VBUS

5

I

Positive Voltage Regulator Input, connected to USB VBUS

GNDBUS

3

I

Regulator Ground, connected to USB Ground (0V) (see Note 1)

VREGA

6

I/O

Positive Regulated Analog Input/Output Power Supply

VREGD

4

I/O

Positive Regulated Digital Input/Output Power Supply

PSM

8

I

Power Supply Mode (Bus-powered or Self-powered)

D+

2

I/O

Positive Data Signal of Differential Data Bus conforming to USB Standard

Specification 1.0

D-

1

I/O

Negative Data Signal of Differential Data Bus conforming to USB Standard

Specification 1.0

TRxD

35

I/O

Transmit/Receive Data Led

DC

36

I/O

DC mask

BUZEN

37

I/O

Buzzer Amplifier Enable/Mute

PULSE

38

I/O

Pulse dialing

DISHS

39

I/O

Disconnect external phone

RFC

40

I/O

Refresh

LED

41

I/O

LED control

CD

42

I/O

Carrier Detect Led

CLID

43

I/O

Caller ID

HO

45

I/O

Hook Control

HSDT

46

I/O

Current sense

RI

48

I/O

Ring Indicator

HC1

27

O

Modem Codec Hardware Control mode selection

PDOWN

26

O

SSI Powerdown bit output (active low)

MCLK

29

O

SSI Master Clock Output

DAASEL

34

I

Select Silicon or Discrete DAA Configuration Mode

FS

28

I

SSI Frame Synchronisation Input

DOUT

31

O

SSI Serial Data Output

DIN

30

I

SSI Serial Data Input

FLTPLL

11

OA

PLL filter analog output. Must be connected to analog ground AGND with

33pF capacitor

DGND

32

I

Digital Ground (0V) (see Note 1)

AGND

7

I

Analog Ground (0V) (see Note 1)

RESERVED

13 to 25-33-44

-

Not connected

RESERVED

47

-

Connect to digital ground DGND

Note 1 : Analog and digital ground pins must be tied together to USB ground GNDBUS.

ST7554

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