JTAG - Joint Test Action Group
JTAG is a standardised interface for debugging integrated circuits which you can use to debug your LubanCat.
There are two separate JTAG interfaces available on the Pi:
- Alt5 on GPIOs 4, 5, 6, 12 and 13
- Alt4 on GPIOs 22, 23, 24, 25, 26 and 27