So at a high level, I have a raspberry pi and an arduino mega that I'm using to drive some speed controllers, and they are connected via serial (and via ISCP for firmware loading onto the arduino). When I piece this all together on my breadboards using breakout boards to handle the 5v->3.3v conversion. But when I take those same circuits, and place them all on a minimal arduino single board that plugs into the raspberry pi, I don't get the same results.
I assume I'm missing something fundamental here, but I cant figure it out. Schematic is attached. What am I missing?
I assume I'm missing something fundamental here, but I cant figure it out. Schematic is attached. What am I missing?