I assume your stepper drivers are good, you mentioned they worked at some point, it would be highly unlikely they all burned out at the same time.
Since you have temperature reading and host communication, your microcontroller should also be fine.
Is it possible that while you were working on the firmware you accidentally modified the pin assignments? Can you try marlin just to see if it works?
Since you have temperature reading and host communication, your microcontroller should also be fine.
Is it possible that while you were working on the firmware you accidentally modified the pin assignments? Can you try marlin just to see if it works?