FS5908

Rev. 1.2

18/22

15. Digital Interface

FS5908 takes I

signal that is the input pin in FS5908, and SDA is two-way serial data I/O pin. For the I/O format, please refer to

SMBus specification.

15.1 Address

Base on I2C interface rules, FS5908 has 7 bits address plus 1 bit read and write control signal (R/W). When

R/W is 0 means writing; 1 means reading. The complete address bytes are as follow:

7

6

5

4

3

2

1

0

A6

A5

A4

A3

A2

A1

A0

R/W

A6 ~ A1 can be setup via programming PROM in the chip.

When A0 is 0, it is 100100.

When A0 is 1, A6 ~ A1 ← PROM9<7:2>

External Pin

Read and Write Control

15.2 Pointer

Pointer is to select the register to read and write. Its corresponding relationship with register is as follow.

Pointer

Name

Length

Status

h’00

REG0

16 bits (2 bytes)

R

h’01

REG1

8 bits (1 byte)

R/W

h’02

16 bits (2 bytes)

R/W

h’03

16 bits (2 bytes)

R/W

h’04

REG4

8 bits (1 byte)

R/W

h’05

REG5

8 bits (1 byte)

R

h’06

REG6

8 bits (1 byte)

R

h’f2

PROM1

8 bits (1 byte)

R/W

h’f3

PROM2

8 bits (1 byte)

R/W

h’f4

PROM3

8 bits (1 byte)

R/W

h’f5

PROM4

8 bits (1 byte)

R/W

h’f6

PROM5

8 bits (1 byte)

R/W

h’f7

PROM6

8 bits (1 byte)

R

h’f8

PROM7

8 bits (1 byte)

R

h’f9

PROM8

8 bits (1 byte)

R

h’fa

PROM9

8 bits (1 byte)

R

h’ff

IDcode

8 bits (1 byte)

R

15.3 Register Writing Process

The process to write FS5908 register via I2C includes:

(1) Write address

(2) Write pointer

(3) Write data

The first byte of writing data is the highest byte of the record, and the first bit of every byte is the highest bit of

the byte.