- DRV8825 Stepper Motor Driver Carrier, High Current
- Arduino Uno microcontroller
- Voltage regulator: LM2936MP (12 V in, 5 V out for Arduino)
- Power supply: S-240-24V 240w
The fault' pin (18) was checked. It seems to not be triggering, but it's been years since I used an oscilloscope. I'm not confident, and it may be triggered low:
If the die temperature exceeds safe limits, all FETs in the H-bridge will be disabled and the nFAULT pin will be driven low.
When I connect a 12 V wall outlet power supply to the driver, no ratchetting occurs. The specs say the driver can handle up to 45 V though. To confirm it is not the fault' pin (18), I will try to figure out how to set the scope to trigger on a falling edge. Besides the overcurrent protection kicking in, what could cause the ratchetting behavior?
Edit: Generic stepper motor specs
Used an off the shelf CNC driver board. It has 100 uF capacitors on each driver:
There may have been LC voltage spikes. So that may be the issue. But I will order a new PCB and populate it with 100 uF caps to truly find out.