I’m playing with some hardware and also trying to look at this issue: Frequency Setting off target · Issue #5 · Pioreactor/rpi_hardware_pwm · GitHub
Is there a test point on the HAT? What ground are the PWM outputs tied to?
Also, I was wondering if the PCB design files are available anywhere. I didn’t see a repo immediately but thought I would ask. Just idle curiosity, no real plans to do anything with them.
By default, the PWM pins are tied to the same 5V rail and GND as the Raspberry Pi. The PWM outputs are controlled by PWMing a specific GPIO pin. The PWM ↔ GPIO mapping is:
"2": 13, # hardware PWM1 available
"4": 12, # hardware PWM0 available
For that issue, you could look at PWM 2 and 4, then.
Note: I haven’t given that issue much attention, because the Pioreactor (so far) hasn’t cared about specific frequencies. The pumps/fans/etc work well enough at 200 hz as they do at 200.1 hz. So I’ve back-burned that issue.
PCB design files will be coming out as we start to open-source the Pioreactor! PCB will be the last part open sourced, but I expect by EOY.