Adding differential stepper signaling to Marlin

Hello! I'm hoping someone with more Marlin expertise than me can point me in the right direction...

I'm building a 3D printer using DM542T stepper drivers, and they require differential signals. I.e., a step+ and step-, etc. I had originally hoped the drivers would work with the inverse signals tied to GND, but after testing it seems they really do need both signals to operate. In theory, I should be able to simply add this feature to Marlin and setup the extra pins, but I'm not sure where I would implement it and digging through Marlin is quite daunting. Could someone give me an idea of what the implementation would look like and what files I would need to modify? Thanks!

Driver like this do work that way. you can either tie - to gnd or + to a logic high

but note 5V/24V logic

This will not work on 3.3v systems, you require a voltage level shifter

Edited 2 time(s). Last edit at 02/08/2024 10:52PM by Dust.

Thank you! I never quite figured out why it wouldn't work, but it seemed like I couldn't tie (-) to common AND use 3.3V input, even though 3.3V worked with the full +/- signaling. I ended up using a Teensy to generate the differential lol.