> >..or build a circuit that generates 8 pulses on each input edge - you
> >could probably do this with a 4017 CMOS counter.
>
> hmm, I had some wild idea about doing that.. but wonderd howto make
> the 8 pulses come evenly spaced and still not overlap into next 50 hz
> cycle if the pulses are too far apart it will still be dong pulse 7 or
> 8 when next 50 hz pulse comes. Tho you got me thinking.. maybe theres
> no need to have the pulses evenly spaced but just fire 8 times as fast
> as it can take it basically - should work.

There's probably no reason that your output can't lag behind the
input by one cycle. I doubt it is something that the user would
notice. That means you can time one cycle, divide the time by
eight and generate evenly spaced pulses while you time the next
incoming cycle. If the incoming frequency varies by more than 1/8
you have a theoretical problem (you haven't finished sending the
last lot before you need to start over). Again, in practical terms,
who cares as long as you are looking for a frequency output, not an
absolute number of pulses.
The times are relatively long so it would be fairly simple to
implement as a couple of software timing loops in a 12C508 and
absolute frequency isn't an issue so the internal RC oscillator
would be fine.

Steve.


======================================================
Steve Baldwin                Electronic Product Design
TLA Microsystems Ltd         Microcontroller Specialists
PO Box 15-680, New Lynn      http://www.tla.co.nz
Auckland, New Zealand        ph  +64 9 820-2221
email: steveb@tla.co.nz      fax +64 9 820-1929
======================================================

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