Pololu High-Power Motor Driver 18v25 Direction issue

Hello,

This is my first post here so please bear with me. I have a Pololu High-Power Motor Driver 18v25 758 which was passed down to me. I am trying to control the speed and direction of a 18V RYOBI drill using this driver and an arduino. I have no issues controlling the speed using PWM but direction is what I am stuck on. The motor will only turn with the DIR pin is set low (GND or 0V) once I set the DIR pin high 5V the motor comes to an immediate stop. According to the truth table the direction is controlled by H or L signal to the DIR pin.

Has anyone else had this issue, maybe the driver is broken since it has been passed down, or maybe my concept is just wrong?

https://www.pololu.com/catalog/product/758

Hello.

Do you have an oscilloscope or multimeter? Can you check if DIR is shorted to GND by doing a continuity test? Can you verify that DIR is actually high when you set it to high? Have you tried starting your motor with DIR high? It is possible that when you are changing directions your motor is drawing more current than your power supply can handle. Looking at the V+ line with an oscilloscope while changing DIR would be interesting.

If the above doesn’t help, can you please describe all of your wiring connections, and the details of your power supply? Also, an in-focus picture of your setup would help a lot.

- Ryan