SN66120B
4-Channel Speech Controller
5.5. Sampling Rate Counters
4 independent sampling rate counters are dedicated to 4 individual voice channels to
play voices with different playing rates. The playing rate is programmable from 4KHz
to 40KHz. The resolution of sampling period of each sampling rate counter is 0.25 uS.
This feature helps SN66120B play sounds with accurate pitches in the case of music
instrument synthesis.
5.6. Auto repetition
Auto repetition function helps SN66120B 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
SN66120B.
5.7. I/O Ports
P1 is a 4-bit input port, P2/P3 are two 4-bit I/O ports and P4 is a 4-bit output port. Any
bit of P2 and P3 can be programmed to be input or output individually. Any valid data
transition (HꢁL or LꢁH) of P1, P2 and P3 can reactivate the chip when it is in
power-down stage.
PAD
To Internal Data Bus
Read Control
Weak
Input Port Configuration (P10~P13)
4
Ver: 1.1
December 6, 2004
SONIX [ SONIX TECHNOLOGY COMPANY ]
