SNC698

4-Channel Speech Controller

5.6 Auto Repetition

Auto repetition function helps SNC698 realize a “looping” sound automatically by

hardware without any software effort. Auto repetition function is a very useful

mechanism to implement “Sustain” sound in instrument synthesis. All 4 channels are

equipped with this function. Arbitrary lengths of looping sound are accepted by

SNC698.

5.7 I/O Ports

P1 to P6 are six 4-bit I/O ports. Any bit of each I/O port can be programmed to be input

or output individually. Any valid data transition (H

L or L H) of each I/O port can

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

Port Data

Port Status

To Internal Data Bus

Read Control

PAD

Weak

I/O Port Configuration

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

Ver: 1.2

August 26, 2003

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