NVIDIA MCPX (MCP-X)
About this component
The MCPX is the Xbox's I/O hub, derived from NVIDIA's nForce MCP and linked to the NV2A over HyperTransport. It runs the four USB 1.1 controller ports, IDE for the hard drive and DVD drive, 10/100 Ethernet (with a separate PHY), the SMBus that talks to the PIC system controller, temperature sensor, EEPROM and video encoder, and the LPC bus to the flash BIOS. It also contains the audio processor (APU) and a hidden 512-byte boot ROM that starts the secure boot chain, which is why modchips and the MCPX revision matter when flashing or modding. It is a BGA part and is not normally replaced. Part variants: Revision 1.0 boards carry the B2 silicon with a USB bug (worked around with a USB daughterboard); 1.1 and later use a revised MCPX with a changed secret boot ROM. Development kits used a different MCPX-2.
Southbridge handling USB, audio and I/O.
Pinout & readings
No pinout or reference readings yet — these show what each pin does and what a healthy part should measure.