The 5V system that I have with open-collectors (a commodore 64) does not have a fixed 5V on the specific port (IEC) that I am going to connect to my 3.3V system (Raspberry Pi).
The Pi however, DOES have both 3.3v and 5v fixed. Would it be possible to use the fixed 5V from the Pi on the HV pin on this board, as long as I connect both grounds from the Pi?
See, I’d rather not take the 5V from a different port on the 5V system, since it would be a little messy with the wiring.