Hello Chris,
i don't think you need 2 crystals, you just need more
creative ways of wasting time with one crystal.
for example, figure out the exact number of cycles that it
takes to process one sample compleyely, then set up a nested
set of loops that will waste cycles until the total is
1/16 second. then do that 15 more times.

you can even sleep the chip in little chunks of time, using
the option register prescaler, the little chunks would be
easier to count than a bazillion cycles.


i dont consider running an f877 at 32kHz a waste, i consider
it a lesson in humility for the mighty pic.

alice
> Dear all,
>
> I'm using a PIC16F877 for analog-digital conversion and datalogging.
>
> I sample at only 16 Hz, and because there is a limit in the number of
> subdivisions of the clock frequency, this requires a 32kHz crystal.
> However, to run the PIC at this frequency would be a waste, so I also
> have a 10MHz crystal for the main clock.
>
> Having two crystals seems to me rather messy, especially as size is
> important (I know watch crystals are quite small, but nevertheless they
> have an appreciable thickness, which I am trying to keep down to 1-2 mm)
> - also it's one more component that could fail, especially as my circuit
> is subject to cyclical loaidng.
>
> Can anyone suggest a way round this problem?
>

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