PWM output on Beaglebne Black 3.8.13 - bone_pwm errors

Hi,

I have tried to get PWM signals to work on my Beaglebone Black, to use it with the DRV8833 Servo Controller (Which needs 4 PWM inputs).

I actually got a tricky Problem, controlling two PWMs of the same Controller.

The Problem is, setting “run” in the pwm_test_PX_XX for multiple times leads to a wrong output.

I did:




# export SLOTS=/sys/devices/bone_capemgr.9/slots```<br># echo am33xx_pwm > $SLOTS <br>`# echo bone_pwm_P9_14 > $SLOTS
# echo bone_pwm_P9_16 > $SLOTS

to setup the Pins.

Then I controlled them by:




# cd /sys/devices/ocp.3/```<br># echo 0 > pwm_test_P9_14.15/run```
# echo 0 > pwm_test_P9_16.16/run

because they initially are turned on.

Now, if I try to
set them on and off again, it often happens, that the output does not match the run values (setting both off and one is still sending).

I encountered that Problem with both 3.8.13 bone50 and 3.8.13 bone70 kernels.

Is there any info about the PWMss I am missing? I havent found very much about that Problem on google…