>
> > 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 ?


Wow, that's a good question.  To be honest, the documentation doesn't
specify the resolution, and since the sensor is currently broken, I have no
way of measuring it.

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


Given that it only gets read ~every 30 seconds, and the computer allows a
large variation and adjust itself.  The sensor is apparently just at a point
that the computer can't adjust anymore.  What I actually hoped was to just
output 50Hz at 50% duty cycle and just leave it be.  Basically, the sensor
is used to measure something that isn't even important, so just making the
main computer happy is what I'd prefer. :)

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


let's see... I've got three nickels and a paper clip.  will that be enough?
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist