[sdiy] dsPIC PWM

rburnett at richieburnett.co.uk rburnett at richieburnett.co.uk
Fri Jul 1 17:04:27 CEST 2016


> On the subject of PWM, does anyone know how the "High-speed PWM" in
> Microchip's Motor Control dsPICs actually works?

Actually just found this explanation...

http://www.microchip.com/forums/m379794.aspx

It looks like the clock frequency is indeed multiplied up to a very high 
rate (480 MHz) and both the rising and falling edges are used for the 
PWM clock, giving an effective PWM clock rate of 960MHz (0.96GHz,) or 
1.04ns resolution!

Might be useful for DCO-type oscillator applications like this:

http://electricdruid.net/roland-juno-dcos/

It will be a lot easier to hit those high-pitched notes exactly when 
dividing down from such a high master clock frequency.  I gather that 
some of the Motor Control dsPICs can also have independent period values 
set for the different PWM output pins too, so they might make a good 
modern replacement for the humble 8253 Programmable Interval Timer!

-Richie,


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