SN56016

4-Channel Speech Controller

5.10. Watch Dog

This is a new function for SN56000 series. The WDT is cascade after system timer.

When user reset system timer will issue a clear signal to WDT also. It would issue a

reset signal to chip if user doesn’t reset any system timer before it reach terminate

count (1 Second) when chip is in active mode.

5.11. I/O Ports

P1/P2/P3/P6 are four 4-bit I/O ports. Any bit of P1/P2/P3/P6 can be programmed to

be input or output individually. Any valid data transition (H

L or L H) of P1, P2, P3

and P6 can reactivate the chip when it is in power-down stage.

Port Data

Port Status

To Internal Data Bus

Read Control

PAD

Weak

Pull Low enable

I/O Port Configuration (P10~P13, P20~P23, P30~P33, P60~P63)

Note: All weak N-MOS’s can serve as pull-low resistors.

5.12. Pull-Low Resister Control

This function provides user to control Pull-Low register of all I/O ports that can be

disabled by user command. With the help of this function, input floating and input pull

low is supported.

5.13. IR Function

P33 can be modulated with 38.5KHz square wave before sent out to P33 pin.

The IR signal can be achieved by this modulated signal.

Ver: 1.0

March 2,2005

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