SNC82085
12-Channel MIDI/Speech Controller
Ver: 1.5 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 LH) 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 Sta tus
To Inte rna l Da ta Bus
Re a d Control
P AD
We a k
