POLOLU ITEM 2133 DRV8825 Driver Module

Support Motor controllers/drivers and motors
1

Hello: I am having this DRV8825 module (#2133) not outputting stepper motor drive signals (A1-A2, B1-B2)… it appears all the inputs are wired correctly:

  1. I am driving the module with 12VDC, 4A Pwr Adapter. Signal states are as follows:

JP2 - Pin 1 DIR Low
Pin 2 STEP Pulsing - square wave, 1Hz (to 2 Hz)
PIN 3 SLEEP High (INVERTED SIGNAL FROM PIN 8 below)
PIN 4 RESET HIGH (INVERTED SIGNAL FROM PIN 8 below)
PIN 5 M2 HIGH
PIN 6 M1 HIGH
PIN 7 M0 HIGH
PIN 8 ENABLE LOW (INVERTED SIGNAL FROM PIN 3-4 ABOVE)

JP1 PIN 1 VMM 12VDC
PIN 2 GND
PIN 3 B2 RIPPLE ( ~ 0 vdc)
PIN 4 B1 RIPPLE ( ~ 0 vdc)
PIN 5 A1 RIPPLE ( ~ 0 vdc)
PIN 6 A2 RIPPLE ( ~ 0 vdc)
PIN 7 FLT An LED (current limited) is attached to this output
PIN 8 GND GND

  1. To keep things simple, I have not connected the Stepper motor to the module yet, hoping to see some activity on the output pins first.
  2. The unit is not getting hot
  3. The LED on the FAULT line turns ON when RESET / SLEEP are activated (driven low). This is strange, as you would expect Fault to go true when the DRV8825 is active, not when it goes to sleep. The Faul LED turns off when RESET and SLEEP are deactivated.
2

Hello.

Can you post some pictures of your setup that show all of your connections, including close-up pictures of both sides of your board? More details about what device you are using to send signals to the driver might be helpful too.

- Patrick

3

Hello Patrick:

Thank you for following up on the issue I had raised in the forum.

It turns out to be a false alarm: Apparently, the DRV8825 Module, with its 0.025" Dia header pins were not making good connection to the 0.600" wide IC socket I had installed. After juggling a bit, it made good contacts, and I believe that was resolved the issue.

Regarding the FAULT line LED being lit, it has to do with a bit of leakage current. To illuminate the FAULT LED, it was current limited by 270 Ohm resistor connected to VDD. A slightly higher value resistor eliminates the problem.

Again, Thank You for your help.

Kirit PAtel

4

I’m glad to hear that you resolved the issues! Thank you for updating us with your solutions.

- Patrick