RPi PWM GPIO Waveform Stability

[mawyatt]

We have a RPi 400 (and 4) that is used as a controller using Python. GPIO 18 (pin 12) is used as a variable clock source to create a 1Hz to 10KHz programmable clock. Using the standard RPi GPIO PWM method produces a clock that has quite a bit of somewhat random period variations, and doing a search for a more stable output comes up with a hardware PMW mode vs. the standard mode but without details on how to implement in the RPi 4 using Python.

Does anyone have a simple RPi 4 with Python solution?

Best,

[thm_w]

https://pypi.org/project/rpi-hardware-pwm/
https://forums.raspberrypi.com/viewtopic.php?t=194839
https://www.electronicwings.com/raspberry-pi/raspberry-pi-pwm-generation-using-python-and-c

[mawyatt]

Already having trouble with pigpiod but didn't know why, got the error message not recognized by OS. After reviewing raspberrypi forum you pointed out, the thread indicated things changed with the I/O structure in the RPi 4 and the DMA worked differently, thus effecting the pigpio. We updated and upgraded Raspbien OS, then the OS would recognize sudo pigpiod and now we can use the pi.hardware_PWM() command.

So it seems this issue has been corrected with the RPi 4 in the latest OS upgrade/update.

Thanks for the help, much appreciated

Best,