Hi Claire,
yes! I think I’m asking the latter point. I am comfortable figuring out how to get a voltage from my microcontroller to some point on a PCB, but I don’t know what I could do to make that useful for the DRV8825 carrier.
Is it enough for me to turn the pot on the carrier board to the lowest voltage possible, and then wire in a pin on my end to try and get a voltage on Vref? I assume I would have to do more to at least disable the vRef system that it’s using right now, and possibly also a few other details. I don’t quite understand the DRV8825 board, but I’m hoping it might be relatively easy to describe how I might go about modifying the system so that I could control the current limit with my MCU.
I am comfortable with some basic SMD reworking, and like I said, the code I’m not too worried about, assuming a PWM signal would be enough for vRef. If I could get away with it, I would run a standard 1khz arduino PWM signal, but if I need to, I could modify the frequency and add passive components to smooth out the signal.
What I don’t really know is how the current control system works and whether what I’m asking is a feasible modification to your DRV8825 board.