Pololu Robotics & Electronics
My account Comments or questions? About Pololu Contact Ordering information Distributors

Am I missing a reset or something on a4988?


Hi guys,

I’m working on getting a nema 17 stepper to work and am kinda lost.

I already fried one controller (it caught on fire and everything)

I bought two just in case I did something bone-headed, so now I’m really cautious because I don’t want to blow up my backup.

I quite carefully followed the tutorial that decrdude posted (thanks) with the step / dir and enable pins all tied to ground. Plugged it in and was able to set the current to 1 amp ( motor rated at 1.5)

After that, I loaded the test sketch on my arduino and ran it. It ran, but was pretty clacky , so I unplugged the motor voltage, and started jumping the MS1/2/3 high per the chart to decrease the stepping mode, looking for a smoother operating mode.

I disconnected the motor voltage, but not the logic as I was doing this. And now when I plug the thing in, I get nothing. I have confirmed that I have voltage where it is needed. I moved all the control pins back to ground to confirm that it is not software-related, and still… When I plug in the motor voltage the coils do not energize.

Is there a order of plugging in that I have missed, or do I need to reset it somehow… Advice is appreciated. Thanks

4988 Sleep Reset


The stepper motor driver does not have the kind of reset you are describing. If it is indeed damaged, there is no way to fix it short of replacing the damaged component. What did you do that caused your first driver to catch fire? What do you mean when you say that the second driver was “pretty clacky”? Can you tell me exactly how you set the current limit to 1 A?

Setting all of the control inputs to ground will result in a disabled driver. The SLEEP and RESET pins must be high in order for the driver to run. Can you tell me specifically how you have your inputs set? I can’t say for sure what might have gone wrong if the driver is damaged, but changing your connections while a device like this is powered is bad practice. If you ever inadvertently brush the wrong net, you can destroy the board.

- Ben


Hello, Ucdwino.

Are you referring to the A4983 and A4988 Getting Started Guide by decrDude? When asking for help and referring to a web page, please provide a link so that the people trying to help you don’t have to go hunting around to figure out what you are talking about. It’s very easy to copy and paste a URL into a forum post, like this: