Fair warning I’m an absolute beginner so there’s a good chance the problem isn’t actually what I’m thinking.
I’m using an AZDelivery DRV8825 Stepper Driver with a CNC Shield V3. I’m trying to adjust the max output on the driver using its little potentiometer, following these instructions. However, when I try to measure the voltage between the potentiometer and ground, I get a reading of zero.
The mysterious thing is, when I plug in the Arduino’s USB cable, then the same measurement will read a value in the range I’d expect (about 1.7V). At least, it will for a while until it overdraws the USB port on my laptop.
I’ve confirmed that the power supply for my CNC shield is yielding 12V at the screw terminals on the shield.
My stepper motor has been connected to the pins for the driver chip since before the first time I powered it on.
Does this mean there’s a problem with my CNC shield? Or is something else I’ve overlooked preventing the driver from getting wall power?