SNC82268

12-Channel MIDI/Speech Controller

Ver: 1.6

Sep. 8, 2006

7

5.5.

IR Function

When IR is enabled, a 38.5KHz square wave is gated with P27. The 38.5KHz IR

signal is present at the pin when P27 is set to “1”.

5.6.

I/O Ports

There are three 8-bit I/O ports P0, P1, and P2.

Any I/O can be individually

programmed as either input or output.

When I/O is set to input, any valid data

transition (H

 L or LH) of each I/O port can wake-up the chip from power-down

mode.

I/O Port Configuration

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

5.7.

Sampling Rate Counters

Each voice channel of 12 is equipped with an independent sampling rate counter to

allow individual sample rate play back per channel. Channel sample rate play back

can be dynamically set from 4KHz to 64KHz. Each sampling rate counter is updated

on a period of 0.125uS. This architecture yields a high-quality music/voice synthesis

that sounds very close to its original source when played through the same amplifier

and speaker circuitry.

IR e n

38.5KHZ

P 27

P AD

"1"

P ort Da ta

P ort S ta tus

To Inte rna l Da ta Bus

Re a d Control

P AD

We a k