Problem with A4988 driver

I am having problems with testing my A4988 drivers.
I have wired the drivers to a mega2560 as per

I added several LEDs to verify state of several of the pins and ran the following sketch.
stepper-drive-real-test_v2.ino (2.7 KB)

  • All inputs test OK.
  • the stepper motor produces light when LED
    connected across coils.
  • It is locked when the sketch is running.

How do I test motor output at the A4988 with multimeter or LED?


Hello, Bob.

From your picture, it looks like you are not using one of our A4988 driver carriers. Since the boards can be configured differently, we cannot offer much advice and you should check with the manufacturer of your board for troubleshooting advice.

Typically, you could test the outputs of the driver to the motor coils to see if you see if the voltage is changing as you expect when you step the driver, so that might be a good place to start.


Just a follow up for any who view this problem.
an LED circuit which can be used to test driver carriers.