[Xenomai-help] Application question

[Travis Stratman <tstratman@domain.hid>]

Hello,

I have an application that I'm trying to solve. I don't have a lot of
experience programming in real-time under an OS, so I'm trying to
determine if this is possible at all and what the best method of solving
it is.

The target for this application would be an Atmel AT91SAM9260 processor
or AT91SAM9G20 (9260 at 400 MHz essentially). The main constraint is
that the ADC in the processor must be sampled at 200K samples/sec which
gives a period of about 5 us. This sampling happens in bursts of 50 to
several hundreds of samples (so at most 2 ms for this task). Once the
data is analyzed, a value is set on a DAC. Once the value has been set
10s to 100s of ms go by before the cycle starts over again with sampling
and analysis.

The timing on the sampling is pretty critical, though a little jitter
might be acceptable at times. In general there shouldn't be much else
going on in the background on the board. The ADC block is rated at a max
312K samples / second.

The 5 us sampling period is too fast to schedule the sampling as a
periodic task. But, since the actual sample burst time is under 1 ms
most of the time I was thinking that I might be able to schedule a
thread to take a certain number of samples in one task, inserting delays
between each sample to get the timing right.

Is this possible or is this an application that should be done on a much
lower level? Am I on the right track at all?

Thanks in advance,

TAS