DRV8825 vref voltage same as motor power supply

Hi all.

So I am using a polulu driver for the first time to controll a desktop CNC, I was lucky enough to get 3 DRV8825 drivers from someone at my uni, apparently they had not yet been used.

Do I attached and tested the drivers according to however the voltage that I get on my voltmeter is exactly the same as the input voltage, What am I doing wrong it is wired up exactly the same as on the polulu website with the minimum wiring configuration. Also the pot turns indefinitely, is this normal_ I was under the impression that they stopped at max and min values. So thanks in advance guys any help with this will be greatły appreciated.



The potentiometer does have stops and you should feel them at the extremes of the pot movement. However, they are not particularly robust and you could turn past them without too much force. Are all the DRV8825 carriers reading the same? Can you post some pictures of your setup? Also, can you tell me more about your power supply’s ratings?


Hi Derrill,

I gave the drivers back this morning did not take photo’s while the were still hooked up, he says they may have been abused by other students, which is a bit of a change from what he told me when I bought them lol thought they were brand new. Anyway I am going to order 3 new ones and hope for the best. Thanks for the help.

PS my power supply is a 12v up to 35A old PC power supply. This should be fine right?

That power supply sounds like it should work, though, I recommend measuring the output to be sure it is what you expect.


Thanks Derrill! Appreciate the advice.