>
>
>    - you say that I still have to manually export pwm0 and pwm1. You mean
>    after mounting your cape, I will have to write a 0 and 1 into the export
>    file of the pwmchip<number> directories in /sys/class/pwm?
>
> Yes.

   - Also which Chip corresponds to which ehrpwm?

This site has a table most of the way down that explains it. However do
keep in mind that it's outdated material, and that now we only have pwm0,
and pwm 1 per module. No, pwm0, pwm1, pwm2, pwm3, etc. Also the pwm
directories will no longer show in /sys/class/pwm, but will now show in
/sys/class/pwm/pwmchipX where X is the chip number.

   - And last but not least, what is the unit of duty_cycle and period? Is
   it ns?

I'm not 100% sure, but ns sounds reasonable. However, I'm not sure the time
period matters so much, as duty_cycle is a percentage of period. So in our
circuit here, which is reverse logic. A period of 2000 with a duty_cycle of
2000 would be 100% duty_cycle. BUt I was just driving LEDs with it, not a
stepper motor or anything period critical.

Anyway, you can always hook the output up to a scope . . .

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