Extensible Host Controller Interface (xHCI) Specification for USB 3.0

The Extensible Host Controller Interface (xHCI) specification describes the register-level host controller interface for Universal Serial Bus (USB) Revision 2.0 and above. The specification includes a description of the hardware/software interface between system software and the host controller hardware. This specification is intended for hardware component designers, system builders and device driver (software) developers. The reader is expected to be familiar with the current Universal Serial Bus Specification revisions. Note: In case of conflicts between the xHCI and the USB specifications, the USB specifications take precedence and must be followed.

The specification is primarily targeted to host controller developers and system OEMs, but provides valuable information for platform operating system and BIOS device driver developers, adapter IHVs/ISVs, and platform/adapter controller vendors. This specification can be used for developing new products and associated software.

Implementation of the Extensible Host Controller Interface specification requires a license from Intel. Adopters of the Extensible Host Controller Interface specification for USB have signed the Extensible Host Controller Interface specification for USB 3.0—Adopters Agreement in order to be licensed to use and implement this specification. This Adopters Agreement provides adopters with a reciprocal, royalty-free license to certain intellectual property rights from Intel and other Adopters and Contributors for their products that are compliant with the Extensible Host Controller Interface specification for USB 3.0.

The latest revision of the specification is Revision 1.0. This revision is an editorial update from 0.96. Revision 1.0 can be downloaded from the link below. All current development should be targeting this revision of the specification.

Adopters can demonstrate compliance of their product(s) with the specification through the xHCI compliance testing program provided by Intel. For details on the xHCI compliance testing program, please send email to xhcisupport@intel.com.