So, I have been following this tutorial on how to run a stepper motor with Arduino using an A4988 Stepper Driver. This is the tutorial: How To Control a Stepper Motor with A4988 Driver and Arduino. I have connected the wires according to this schematic:


I have connected the wires exactly like this and triple-checked it! The problem is the stepper motor is not turning. This is the code(it's simple):

// defines pins numbers
const int stepPin = 3; 
const int dirPin = 4; 

void setup() {
  // Sets the two pins as Outputs

void loop() {
  digitalWrithe(dirPin,HIGH); // Enables the motor to move in a particular direction
  // Makes 200 pulses for making one full cycle rotation
  for(int x = 0; x < 200; x++) {
  delay(500); // One second delay

One weird thing:

When I connect the sleep and reset pin on the A4988 board the stepper motor starts turning. Like why?

NOTE: I replaced the MEGA with a UNO because at the moment I'm just testing.

  • Have you tried pulling Sleep and Reset to HIGH, like shown on page 1 and 7 of the A4988 datasheet?
    – chrisl
    Commented Apr 11, 2020 at 11:55
  • I have NOT. Because I didn't see it. Wait I'll try it out. Thanks! Commented Apr 11, 2020 at 11:57
  • I have the same problem. My motor is vibrating but not realy moveing. Can you help me?
    – PurpleOwl
    Commented Apr 1, 2021 at 23:44
  • @PurpleOwl See the answer below, that's what I tried and it worked for me. You essentially need to connect the sleep and reset pin together. If they still don't work, see the debugging options below. Commented Apr 3, 2021 at 7:19

1 Answer 1


You have to connect the sleep and reset pin together. I assume that you took this schema on how to mechatronics. In his video you see that the sleep and reset pins are connected. I don't know why but it has to be like that.

Then, if the motor vibrates or click, it may be one of these problems:

  • You didn't connect the motor properly
  • The current is set too low on the board (screw on the motor driver)
  • The battery (Vmot) isn't powerful enough

If it's not one of those problems, the A4988 chip might have an issue. I have a similar problem where it turn in one direction and only when the pwm signal goes throught the direction pin instead of the step pin.

  • Thanks! The question is from about two years ago. So, I figured it out myself then. But appreciate your effort and am accepting it as an answer. Thanks again :) Commented Dec 17, 2020 at 18:21

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