> I have now downloaded the AN696, and it's now
> clear that Al was talking about high resolution
> encoders (500 counts per revolution in the AN696).
> I was thinking about those small encoders you
> use as input devices on front panels. I can see that
> these high res encoders easily can produce more
> steps/sec then the PIC could handle with ease, and
> the solution as described in the AN seems reasonable...

It all depends on shaft speed.  I've got a 16F876 at 8MHz tracking a 1000
counts/rev shaft encoder using port B change interrupts.  This is doing the
full 4x quadrature decoding, so it's actually dealing with 4000 events/rev.

The top speed of this particular system is only 3 RPM (20 seconds/rev), so
there is an event every 5mS on average.  However, even this setup could
handle significantly faster without modification, and even faster with a
20MHz crystal (which wasn't used to save power because the cycles just
weren't needed).


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