July, 2007

V0.27P

- 8 -

F75111

6. Functional Description

6.1 General Description

Dedicate GPIO functions. That includes two sets of watchdog timer. One Set of Watchdog timer timeout unit is set to second

and range is 0 to 127 seconds. The other Watchdog timer is set to second or minute and the range is 0 to 256 seconds or minutes.

When the timeout has occurred, that will generate a status bit to indicate it and write one will be clear. All GPIO can be programmed

to logic one or zero or high pulse or low pulse.

6.2 Access Interface

The F75111 provides one serial access interface, I2C Bus, to read/write internal registers. The address of Serial Bus is

configurable by using power-on trapping of standby power VBS3V. The pin 3 (GPIO13/I2C _ADDR) is multi-function pin. During the

VSB3V power-on, this pin serves as input detection of logic high or logic low. This pin is default pull-down resistor with 100K ohms

mapping the Serial Bus address 0x9C (1001_1100). Another Serial Bus address 0x6E (0110_1110) is set when external pull-up

resistor with 10K ohms is connected in this pin.

6.3 The SMBus access timing are shown as follow:

0

Start By

Master

0

1

011

0

1

D7

D6

D5

D4

D3

D2

D1

D0

Ack

by

111

R/W

Ack

by

111

SCL

SDA

D7

D6

D5

D4

D3

D2

D1

D0

Stop

by

Master

SCL

SDA (Continued)

78

0

7

8

0

78

Frame 2

Internal Index Register Byte

(Continued)

Frame 3

Data Byte

Frame 1

Serial Bus Address Byte

Figure 1. Serial Bus Write to Internal Address Register followed by the Data Byte