36v20 Motor Driver - Direction does not change


I am using the “Pololu High-Power Motor Driver 36v20 CS” with Arduino. I have only connected the GND, DIR and PWMH pins to Arduino, and with this configuration I can successfully run the motor at different speeds. However I can not change the direction. I am simply sending HIGH or LOW signal to the DIR pin, but the direction does not change, always CWW or CW depending on the wiring. In order to confirm that Arduino is actually sending HIGH and LOW signal; I have used a volt meter when the motor driver was off, and I get 5V for HIGH and 0V for LOW.

A few weeks ago when I tried it, I could change the direction. Now I am wondering if I have damaged the board? But I doubt this possibility because I can control the speed of the motor.

I would appreciate any help, thank you.


It is possible that the pin was damaged, or there could be a bad connection to that pin. If you post pictures of your board, I can examine the board and connections to see if anything looks like it might be causing the problem.

- Grant

Grant, thanks for your reply.

I have attached the pictures of the board, back, front and with Arduino connected. As I have mentioned earlier, only three pins are connected from arduino, GND, PWMH and DIR(HIGH or LOW).

There is a remote chance that the pin burned out; however, you should first reflow the solder to make better contact between the pin and the pad. We have some suggestions and links about soldering in the General troubleshooting advice section of our support page that you might find helpful. While you are resoldering your connections, you might consider increasing the wire gauge for the motor and power connections and soldering them directly to the board to better accommodate the current going through those wires. (Breadboards are typically only intended for low current applications.)

Once you have cleaned up the solder for the connections, you could check your connection to the DIR pin by using the continuity setting on a multimeter and touching one probe to a wire connected to the DIR pin and the other probe to the resistor pad circled in red on the following picture.

- Grant