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From: Eric.Thayer@cs.cmu.edu (Eric H. Thayer)
Newsgroups: comp.sys.next
Subject: Re: Help needed about DSP C functions...
Message-ID: <1990Nov14.163831.15377@cs.cmu.edu>
Date: 14 Nov 90 16:38:31 GMT
References: <10@homer.cs.mcgill.ca>
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Organization: Carnegie Mellon School of Comp. Sci.
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Admittedly, this stuff is a little daunting the first time out.  There are 
a number of ways to communicate to the DSP.   My suggestion is to dig into 
the example code provided in
/NextDeveloper/Examples/DSP/SoundDSPDriver/dsp_example_[1234].  This code 
works (with one change that I am aware of).  You can do timings and 
performance analysis of communcation overheads/throughput using this code. 
 From that, you can decide how much coding complexity you are willing to 
live with given the constraints of your application.

The code that needs to change is the bit where the device and owner ports 
are acquired/released.  You should look up the summaries for SNDAcquire 
and SNDRelease and replace the existing code with calls to SNDAcquire and 
SNDRelease.  If you don't do this, things you build using the example code 
don't interact well with code that uses SNDAcquire and SNDRelease (I am 
not sure why, but NeXT recommended I use SNDAcquire/SNDRelease instead of 
what is shown in the demo code).  Thankfully, this has been fixed in the 
example code in prerelease 2.0.

 Also, DEFINITELY get the DSP56000 UM/AD (User's Manual) and be thankful 
that you are working from a Rev 2 manual and not a Rev 0 manual.

 This is basically how I got bootstrapped (with some help from some 
friends). 

In article <10@homer.cs.mcgill.ca> philwzo@quiche.cs.mcgill.ca (Philippe 
WIECZOREK) writes:
>         I have trouble with understanding the organisation of the DSP
>         memory too... Is someone able to explain it to me ?

Can you be more specific?



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