A4988 get`s hot, but no reaction from Motor

I am using the a4988 to drive a Nema 17 (4V, 1,2A).
Have already adjustet the current on the Potentiometer to Vref = 1,2A*(8*0,05Ohm)*70% = 0,33A

This is my Code: (using the accelStepper library)

#include AccelStepper.h>
AccelStepper motor(1, 6, 5); // pin 6 = step, pin 5 = direction
void setup() {

void loop() {

This is my wiring diagram: (Arduino powered with usb)

I managed somehow to make to stepper move (it did not do what it was supposed too, but it moved).
But now the stepper does not do anything besides the a4988 getting really hot at the resistor above the power input…

Have i fried the a4988, wired it incorrectly, or is something else wrong?


The connections in your diagram look fine. What are you using to supply motor power? Could you post pictures of the actual setup showing the connections?

I am not that familiar with the library you are using. Could you try using the example provided in this library?

By the way, I am not totally sure what current limit you were trying to set with your equation, but. since your stepper motor is rated for 1.2A per phase, you would normally set Vref to 0.48V. However, since the continuous current rating of the board is only 1A, you should set Vref to limit the current to 1A (Vref = 0.4V) instead. If you only intend to use the motor in full-step mode, you can increase that to Vref = 0.57V, since the driver will only actually set the current to 70% of the current limit.