I have both the $4 board and the $10 one plus the associated software. I can find a pulse width generator but don't see any way to have either the frequency or the duty cycle modified--what am I missing? I can set it but there seems to be no way to vary it once set.

 

Two ways, instead of using clock straight into PWM use clock followed
by freq divider then into PWM. Under SW control change the divider ratio
hence the period fed to PWM clock input. Thats the example I attached
in the earlier post.

Or use the period and compare (duty cycle) APIs of the PWM directly to
change the period under software control. Right click the component, then
datasheet link, and the APIs are in there and their description. I think its
even possible using DMA in the 5LP parts to change the PWM period
using HW only.That's more involved getting the DMA setup though, there
are videos and ap notes on DMA.

Regards, Dana.

 

A PIC that has 10-bit control (e.g, enhanced mid-range ones)should give 5-bit resolution at 1 MHz with a 32 MHz clock. You can extrapolate from the charts in the datasheet (e.g., 250 KHz =7 bit), calculate manually, or cheat here (http://www.micro-examples.com/public/microex-navig/doc/097-pwm-calculator.html).

You are right. I forgot about the two extra bits. So, 32 duty cycles it is.

Bob