The datasheet says "This motor driver is driven by high power MOSFET, with the control signals opto-coupler isolated to protect any delicate circuitry and ground loop issues."I did connect to 3.3V and not 5V of Pi 5 and my original code (first post) worked, what happened?Actually, I wonder if you need to supply 3.3V instead of 5V.
Presumably they have connected the opto-isolator between the pin labelled 5V and the GPIO. If the GPIO only gets up to 3.3V when high, then it'll still have 1.7V across it which may still be registered by the phototransistor.
Connect to 3.3V instead of 5V and the opto-isolator has 0V across it when high, so it definitely won't be registered by the phototransistor.
(That does make me wonder why they need a ground connection at all there. Possibly only to illuminate the "Control Logic Power" indicator).
Statistics: Posted by 6by9 — Wed Dec 10, 2025 11:42 am