[sdiy] Sequencer interrupt latency?

[Roman]

funny you should mention that. I'm starting a PIC based sequencer
firmware...
anyway, 40us is pretty good. That's one cycle of 25kHz. Nobody could notice
that.
With times 10 times that much you could notice something with sequences
running
at audio frequency, but still it would be very short.
Whole world depends on MIDI and it takes entire milisecond just to send a
note
message alone.

Roman

----- Original Message -----
From: "Speth, John" <John.Speth at coherentinc.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Monday, April 12, 2004 4:54 PM
Subject: [sdiy] Sequencer interrupt latency?


> Hi folks-
>
> I'm finishing up a PIC based sequencer and now I'm optimizing for
performance.  My step input feeds the interrupt input.  When a step
interrupt is serviced, the analog out is set, then the step trigger is
asserted, and finally the right LED is lit up.  My question is:
>
> From your experiences, what is the maximum acceptable latency from step
input to analog out and step input to step trigger?
>
> By "maximum acceptable latency", I mean that maximum time that it becomes
noticeable under non-audio rate applications.  Right now, I'm getting about
50 usec latency to the step trigger which means I get maybe 40 usec to
analog out.
>
> Thanks...
>
> John Speth - john.speth at coherent.com
>