PPC-IOP UART
The PPC-IOP UART RX and TX are accessible through an unpopulated connector footprint located on the B side (underside) of the motherboard (together with the EE UART and some other signals). This connector footprint seems to be consistent across all 75K and later models. The PPC-IOP UART signals use 3.5V logic levels and the baud rate is 57600 bps. When powered on or reset the following message is sent:
D E C K A R D compiled $date
UART location on SCHP-75K (GH-040-??):
UART location on SCHP-75K (GH-037-12):
Photo credit: El Isra