Specifications

DSP Commands 6-23

Program 16-bit DMA mode digitized sound I/O

Output bCommand, bMode, wLength.LowByte, wLength.HighByte

Remarks The bCommand byte is organized as:

D7 D6 D5 D4 D3 D2 D1 D0

1 0 1 1 A/D Auto-Init FIFO 0

0 = D/A 0 = SC 0 = off

1 = A/D 1 = AI 1 = on

where D/A stands for digital-to-analog,

A/D for analog-to-digital,

SC for single-cycle DMA mode,

AI for auto-init DMA mode.

FIFO will be re-initialized when the DSP receives any new digitized sound I/O

commands.

The bMode byte is organized as:

D7 D6 D5 D4 D3 D2 D1 D0

0 0 stereo signed 0000

0 = mono 0 = unsigned

1 = stereo 1 = signed

where the signed bit determines whether the data is signed or unsigned. For

minimum signal amplitude, the signed 16-bit value is 0000h; with unsigned data, the

equivalent value is 8000h.

wLength is a word giving the number of 16-bit samples less 1.

Refer to command

1Ch

on how to terminate auto-init DMA mode.