How to check A4988 with no microcontroller

Hello, i have tried using the A4988 with a raspberry pi but that resulted with a fried raspberry pi and nothing working. Right now i’m trying to manually step the motor by having a pullup resistor in the step pin but that is not working because the output pins only give 12v @ 0.4A.

My configuration is vmot and gnd to 12v and gnd with a 100uF capacitor in parallel. A1,A2,B1,B2 to appropriate stepper motor pins. Vdd and ground to 5v and gnd. Enable, ms1, ms2 and m3 left floating. Reset and sleep connected to each other. Step with a pullup resistor to vdd and dir connected to gnd. But nothing is working when i tap the step pin with gnd.

And please could i get a refund for the raspberry pi. Everything was wired up according to your diagrams but it broke the raspberry pi. No pins were floating, both were logic 0. For me it makes no sense that the board is not functioning correctly.


I am sorry to hear that your Raspberry Pi is damaged and that you are having trouble using the A4988. Although it is not entirely clear how the RPi was damaged, it seems unlikely that an A4988 would damage a Raspberry Pi if they were connected correctly. Can you post a schematic that shows how you had the RPi connected to the A4988 and the rest of your system when the RPi was damaged? Can you also post pictures that show your RPi and the A4988, including any soldered joints? (If there is visible damage on your RPi, can you make sure to focus on that for the pictures?) What stepper motor and power supply are you using (if you can, please link to a product page or datasheet for them)?