I. AUDIO DRIVER DESCRIPTION
DMAR0 is generated once for the stereo pair of audio samples. The first
read after from that address reads left channel, the second
read reads right channel. Similarly, The first write after DMAR0 from
that address writes left channel, the second write writes right channel.
InitA.asm sets up the audio driver as the chained sequence of DMAs
(all channel 0).
--> RxLeft --> TxLeft --> RxRight --> TxRight --
| |
------------
RxLeft is setup to read CODEC's external address (0xc0000000) into
internal memory location _ReadDataLeft.
RxRight is setup to read CODEC's external address (0xc0000000) into
internal memory location _ReadDataRight.
TxLeft is setup to write variable WriteDataLeft to CODEC's
external address (0xc0000000).
TxRight is setup to write variable WriteDataRight to CODEC's
external address (0xc0000000).
This little description is from a code example given with VisualDSP++. I
don't quite understand the two channels.....why two channels for input? why
have a left and right channel? and what data will flow in from the left and righ
channels? Once i know what data will be available i know how to handle the
interput. Anyone with indepth knowldge of how these channels work in relation to
the audio, you help would be much appreciated.
