Henrik HolmgŒrd wrote:

> So now I got the idea to try the same approach with a 16C84, but using
> the internal prescaler in combination with a software divider to
> generate a 1Hz signal from a 5MHz crystal without external divider.

  I take it to mean you want to generate 1 Hz from a PIC16F84 with a
5 MHz crystal.  Should be dead easy.

> I have however some difficulties to get this idea to work in the real
> PIC world.

  OK, tell us your difficulties.  Difficulties getting a PIC to work, or
can't figure out the programming?  What sort of 1 Hz do you want?
Sinewave?  Squarewave with 50% duty cycle?  Pulses of what width?  What
is the acceptable jitter (in microseconds)?

  If this is the only thing you want to do with the PIC, a hardware
divider would probably be cheaper, so do you want it to do something
else at the same time?

  Among PICs, the 12C508 would be cheaper than a 16F84, though you need
slightly smarter hardware and a "JW" chip to develop on.  There's
supposed to be an even cheaper 14-pin chip, but no-one knows if the
vapour has settled yet.
-- 
  Cheers,
        Paul B.