The Wii U has a standard AHCI 1.2 SATA controller onboard. It identifies as having two ports (0 and 1) running at 3Gbps. In retail systems, the disc drive is connected to port 0; while port 1 is disconnected. Unused code in IOS-BSP indicates that port 7 may be present on non-retail units.
In terms of hardware registers; the controller lines up with the specification starting at address 0x0D160400; that is; the first Generic Host Control register (Host Capabilities) resides at 0x0D160400. On a retail console, this register reads out 0x7720FF81.
* The generic host control registers start at 0x0D160400.
* The port registers start at 0x0D160500.
== ATAPI commands ==