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Date: Fri, 12 Feb 2016 17:02:12 -0500
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On 2/12/2016 4:47 PM, DJ Delorie wrote:
>> The drive for that chip is out of the audio range.
> The trace he posted says 10KHz, that's within *my* hearing range.  The
> question is, is there something that's turning that into mechanical
> noise?  Are there other variances in the PWM signal that might be
> audible?

The PWM is in the 60k range.

He is stepping the motor at 10k.

That might be the problem.

It is probably also why there is some timing glitch around 3k.

Just my two cents.

Phil