I know there are many threads about 7segment displays and the Max7219.
But non of those seem to address what I’m currently seeing and I’m hoping to get some input on how to go on from here.
The setup is the following:
2 max7219 daisy chained on a PCB.
Power is coming from an external source which has a common GND.
Now the challenge is that this does work if I connect it to an Arduino Mega 2560.
But if I connect the same PCB to an Arduino Mega 2560 Pro board, only the first 8 digits work. the second set is always blank.
I also did try it with 2 different Mega Pro’s and it’s exactly the same behavior.
Now I do get that those are not the original ones. But except for some pins which do not work at times I didn’t have big problems before and it works with everything else I have connected.
Anyone knows what could explain this wired issue? I have a hard time to understand what could cause this difference as we are talking about having 3 pins here which don’t really have any load.
(Btw, nothing else is connected while I try this.)