jojocaster:
I'm afraid the displays might be CA ...
MAX7219 can be used with CA. Its not as convenient...
- You have to switch digit decoding off and have digit patterns in your code
- You cannot reduce the "scan limit" to maximise the brightness of the displays, because you need the chip to scan all 8 "digits" to light all your segments
- You have to update all 8 digit registers in the chip to change one digit on the display
- You have to do some tricky bit-manipulation in the code...but it can be done.