After wrapping up a 40-year career in mainframe programming, I'm just learning how to use micro processors. I've had pretty good success so far with Arduino, but I've run into a brick wall on the current project. I would surely appreciate any help you experts could give me!
I've got a Nano Mega328 feeding SPI commands to a MAX7219 mux LED driver. The setup runs a small 4-digit display perfectly, (COTCO LD2-BW30GU-C11).
My problem is trying to drive a larger 5" display (MAXX MXA002) which needs 12 volt. I have the 5-to-12V converter board (MXA008) made by the same company.
While the COTCO display is scrolling numbers just fine, at the same time, the MAXX segments are all on at full brightness. There are some very slight intensity changes, as digits change on the COTCO display. (I'm only using one MXA002 digit to test.)
[Schematic below updated to show two caps and a resistor.]
Any suggestions? The manufacturer in Thailand was unable to help me.
The data sheets are pretty sketchy for the MAXX components:
If it helps, here's a short clip from a week ago when the COTCO display first went live