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Re: Interrupt-based ADC scanning and filtering

2004-05-06 by djbrow54

I've rewritten the code to shorten the number of samples to 4.  I've
also interleaved the sampling so that IN-1 is sampled every 2 mS,
IN-2 is sampled every 4 mS, and IN-3 and 4 are sampled every 8 mS. 
This allows me to sample one input every 1 mS timer interrupt.  The
current code requires 250 uS execution time per interrupt so it's
consuming 25% of the available cylcles.  Next week I'll work on
optimizing the code.  I can make it simpler and faster for only 4
samples.

Dave


--- In SynthModules@yahoogroups.com, "grantrichter2001"
<grichter@a...> wrote:
> > Is an 8 samples average too much?
> 
> I think it is too much. Two sample averages, or four should be 
> enough to solve the problem.
> 
> > Is an update every 32 mS too slow?
> 
> Latency of under 3 milliseconds is considered good, but less is 
> better. A rule of thumb is all channels should be updated within 1 
> millisecond (for example the Buchla keyboards scanning speed 
> is 1 millisecond divided by the number of keys).

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