Raspberry Pi IO header to JTAG IDC-20P connector, plus optional UART connectors and power indicators.
Note that JTAG pins are shared with GPIO, which you will need to re-configure in order to enable JTAG. I use my minipi bootloader to do this, which gives me access to JTAG early in the boot. But you can also do this manually from the u-boot prompt:
mw.l 0x3F200000 0x00002000 mw.l 0x3F200008 0x0061B0C0
CERN OHL v1.2, because lets face it, this is rocket science ;)
see LICENSE for details