12f629 freq divider?

[nomad]

My output frequency will be constantly changing. but that's a good idea to remember, certainly gets around pwm limit. my whole circuit is reading time of an input pulse, displaying the frequency, adding or subtracting a variable amount (from button inputs to a counter) and outputting the new frequency. had it all done up with logic, counters, a pll, display drivers etc. just moving to a cleaner(simpler) solution with a pic. as an after thought was thinking the divide by 50 could also use internal DAC 25 steps up then down and get a dirty little sine wave out. ?

[Kamikaze47]

Using the method I suggested, you could easily change the frequency by changing the number that you subtract from the timer.

[nomad]

ok, guess i was looking for the easy way out. am a newbie and haven't dealt with the timers yet. just assumed it would be difficult to change on the fly. having it all done in the one pic would be best. i'll read up and let you know how it turns out. thanks!

[Darrel Taylor]

the easy way out ...

Slow speed Software PWM
http://www.pbpgroup.com/modules/wfse...hp?articleid=6

Set the dutycycle to 50%
Then change the frequency at will.
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[nomad]

Thanks! now to go read and understand it. Really appreciate the replies.

[talat]

the easy way out ...
Slow speed Software PWM
http://www.pbpgroup.com/modules/wfse...hp?articleid=6

Set the dutycycle to 50%
Then change the frequency at will.
<br>

Hi,
how I can use SSPWM (Slow Speed PWM) code with 12F675?

[skimask]

Hi,
how I can use SSPWM (Slow Speed PWM) code with 12F675?

You can't.
Not enough on chip register space for the variables required.

[Darrel Taylor]

Where do you come up with your answers skimask?

8-Ball?
Dart board?

Of course you can run it on a 12F675.
Just comment out the wsave1 wsave2 and wsave3 variables, since the 12F675 doesn't have GP RAM in those banks.
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