RNGolding@aol.com wrote:
> I'm currently using a PIC18F4423 (but that can be changed if
> unsuitable). Generating a 10bit PWM at a single frequency is pretty
> straightforward using a  suitable master clock frequency and Timer 2
> values but
> I can't see how to get other frequencies (via PR2 value) without
>  losing the 10bit resolution. i.e. setting a PR2 register value below
> 255 to set the other  frequencies reduces PWM resolution.

It sounds like the standard 16/18 PIC CCP module is not suitable for what
you are trying to do.  You probably want to use some sort of dsPIC, like a
24H.  The PWM period generation is much more flexible.  Even with the norma=
l
"output compare" modules, you get PWM period resolution down to one
instruction cycle.  At the maximum speed of 40 MIPS, you can achieve a
minimum of 10 bit resolution at 39 kHz and lower.  The duty cycle and perio=
d
registers are 16 bits, so you have 6 bits of headroom in your case.  The
lowest PWM frequency you can achieve at 40 MIPS is 610 Hz without any
prescaler.  Clearly there is lots of room for you to get 10 bit resolution
at a range of frequencies.


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