Re: [Gumstix-users] round number robostix PWM frequency

[Dave H. <dhy...@gm...>]

Hi Chris,

> I would like to set my motor PWM frequency to be a multiple of 60 Hz.
> My controller does sampling and having the motor be a multiple of 60
> Hz would simplify the design of the IIR noise filter.  Is it possible
> to trick the Atmel into this?  Right now I have 976.5625 Hz and I'd
> like 960 Hz.

16,000,000 / 960 =3D 16,666.6667

So you can't get exactly 960 Hz.

16,000,000 / 16667 =3D 959.98 Hz.

So using the servo sample, as a base, modifying the prescalar to be
divide by 1, and setting the ICRx register to 16666 (there's a +1
according to the datasheet) will give you 959.98 Hz.

--
Dave Hylands
Vancouver, BC, Canada
http://www.DaveHylands.com/