Preliminary

SNC749

16-bit Voice Processor

Ver. 1.8

March 6, 2007

9

7. I/O PORT

SNC749 provides one a 24-bit I/O port for user application (P0.0~P0.15, P1.0~P1.7).

The input pull high resistor of each pin can be programmed by Port Pull-High register.

The direction of I/O port is selected by Port Direction register.

The Port0 (P0.0~P0.15) and Port1 (P1.0~P1.7) can wake the chip up from the stop

mode and watch mode. P0.15 can be modulated with a 38.5Khz carry signal to realize

IR signal transmission.

When user uses GPIO to wake up chip, the GPIO must setting to input mode and

Pull-High all I/O pin.

I/O Configuration of P0.0~P0.15

Pull-Up

Resister

Latch

PAD

to internal bus

Pull-Up

Select

In/Out

Control

In/Out

Control