Thanks for your quick reply and clear video: appreciated! Afterwards I was able to see the 'device' and 'output' section with reference to XPDR_CODE in the generated 'data.cfg'.
Unfortunately that did not light up anything.
So back to your question first: yes it is a common cathode display. I think the MAX7219 can only handle that type, and the pure Arduino code seemed to work just fine.
That leaves me to the wiring specific to SimVim:
- CLK to PIN 37
- CS to PIN 28
- DIN to PIN 27
Can you confirm?
To avoid as many mistakes from my side, I also tried the same with a 8 digit 7 segment pre-build setup, but the outcome was the same. Nothing lights up.
Other buttons I add seem to interface as expected (so there is definitely traffic going back and forth).