A Tutorial for the programmation of the sound/DSP driver for real time sound processing.


This directory contains:



· 01_Intro
Documents, thing to know before getting started...

· 02_Cfunctions
Describes the classes of C functions relative to the sound and the DSP. You should know of these functions (and where to look for them) before writing anything, so that you don't write something that already exists.

· 03_Play_Dacs
Play_Dacs is a simple example of how to set-up a stream from the memory to the DACs, open a sound file, play it on the stream and control the play-back. It does not use the DSP. The example to start with.

· 04_Rec_Mike
Rec_Mike is an example showing the basic way recording can be done. This example records from the microphone, and therefore is not very useful. But the mechanism of recording remains the same whether you record from the microphone of from the DSP. It does not use the DSP.

· 05_Dig_Ears
Dig_Ears shows how to set-up a stream from the DSP to the DACs, and get samples from the SSI port. If you have MetaResearch's Digital Ears, you can plug them in the DSP port, and use this example to play a source in real time through the DSP to the DACs. It uses the DSP, shows how to set-up the streams and the DSP, and how to pass data to the DSP to control its action on the sound (e.g. the volume at which the sound is played back etc...), and how DMA functions. If you have nothing to plug in the DSP port (no Digital Ears etc...) you can make the DSP send a pure sine wave instead (see the C program.)

· 06_Play_Through_DSP
Play_Through_DSP is an example showing how to play a sound through the DSP to the DACs using non DMA transfer from the host to the DSP and DMA from the DSP to the host. It shows you how to pass data to the DSP in a non DMA way.

· 07_DMA_To_DSP
DMA_To_DSP shows you how to set-up a DMA stream from the host to the DSP then to the DACs, and play a sound on it. It involves DMA transfer in both directions. The faster rate of transmission of DMA makes it possible to reliably play sounds at 44100 stereo (provided the high water mark in the driver is high enough, see the C program.) It also illustrates a scheme for passing data to the DSP while it's playing back the sound.

· 08_PitFalls
This is a huge sack where all the hints about the driver and the DSP are grouped. This is the trouble shooting part of this tutorial. Turn to it if you have a problem!

· 09_Future
Future investigations, things to check etc...