USB

The PS3 contains two USB 2.0 host controllers (EHCI, with OHCI companion controllers), each with a two port root hub. These ports are connected to on-board peripherals according to the following diagram:

Note that the external USB ports are not connected directly to the root ports, but to a separate USB 2.0 hub. Because of this, only USB 2.0 units will be connected to the root port, and a driver implementation using the EHCI interface will not need to implement OHCI as well.

The first port of the first USB host controller does not seem to be connected to anything. Possibly it is used as a debug port or something.

The memory card reader is only present on the 60 GB model of the PS3. Presumably the corresponding port is just left unconnected on the 20 GB model.