BKM129X clone firmware.
Based on https://github.com/skumlos/bkm-129x-mcu Adds RGB status LED output.
Red - card has power, but was never initialized by the PVM.
Yellow - card ok, but not selected as input.
Green - card ok, selected, sync on.
Blue - card ok, selected, sync off.
I have used SK6812 5050 LEDs, but you can use any you want.