I'm having trouble getting my stepper to engage, or power up with the A4988. I copied the schematic from RAMPS for running a NEMA14 from an Arduino Micro. With my DMM I am seeing:
STEP and DIR: 5v or 0 depending on what I set it in the sketch. SLEEP and RST: Connected to each other, reading 5v Enable: 5v MS1-2: 5v or 0 depending on jumpers VDD: 5v VMOT: 12v All of the GNDs have continuity to the ground plane 100uf capacitor connected to VMOT and GND reads 12v Each of the pins of the motor connector have .8v The VREF is set to .6v
The motor is silent. No vibration, no noise, no torque. I've tried two different motors and drivers, adjusted the pot.
I set up a driver and a micro on a breadboard, and can get the motor to buzz. The only difference between the breadboard and the PCB is the breadboard didn't have a capacitor on VMOT, no resistors for EN and MS1. The breadboard used different pins on the Micro for STEP and DIR.
I know the issue isn't the Arduino, because I can set STEP and DIR high or low, or make it switch back and forth. I reused the capacitor from another board, but even if there is an issue with it, I still get 12v on VMOT. RST and EN are high. I can't think of where else to look for problems. If all of the wires to the stepper have voltage, why is the motor dead?
I'm using a simple test sketch that switches STEP from HIGH to LOW followed by a delay. pinModes are OUTPUT, and set to HIGH during setup.
If I check the voltage for each motor wire to gnd, should I see current on all of them, or only 1 or 2 of them?
There are two stepper drivers on the board, I've highlighted one of them.