> Is it possible to specify (for lack of better words) a specific frequency
> for the PIC to output?  Can the PIC (speficially the 12F629) combine
> the frequency with PWM?

Hi Philip, putting out 50Hz is easy. What resolution (granularity) do you
need for the 30-70% ? And how is it changed ? And how quickly must
it respond ? I have a similar project using an 18F that outputs a variable
frequency (about 150-250Hz) and a variable duty cycle. Both are
adjustable with pots on the ADC. The duty cycle is in 1/64th steps ->
on mine 30 - 70% would actually be 19/64 (29.69%) -  45/64 (70.3%)
in increments of 1.5625%, which is acceptable in this application. As you're
wanting a fixed, lower frequency, you could use the same method with 128
steps, or use individual instruction cycles (eg the PWM module or timer or
loops) to get much finer resolution. There is a trade-off using the PWM
module. If you want high resolution you have to run the clock faster, and
that raises the lowest frequency that can be put out

> I figure this must either be really easy or really hard

As above, it really depends on what you want and what is acceptable
as a compromise

>... If anyone can help me out, I'd be in your debt. :)

Send money, women, to......

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist