Universal Host Controller Interface (UHCI) Design Guide

This document describes a Universal Host Controller Interface (UHCI) for a device that implements a Universal Serial Bus (USB) Host Controller. The document is intended for hardware vendors. The UHCI description covers the hardware/software interface between the Host Controller Software Driver and the Host Controller hardware (shaded area in Figure 1). It describes the register-level hardware interface to the USB Host Controller. Hardware developers may take advantage of the standard software drivers written to be compatible with this Universal Host Controller Interface by conforming to the register level interface and memory data structures described in this document.

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OpenHCI -- Open Host Controller Interface Specification for USB

Preliminary Publication Date:	September 1995
Version 1.0 Publication Date:	December 1995
Revision 1.0a Date:	October 1996

New OpenHCI and USB information coming soon to this page!

This document is the latest preliminary revision of the OpenHCI (Open Host Controller Interface) Specification, Rev. 1.0a released to the public in October 1996. This version replaces Rev. 1.0 released in December 1995.

This revision of the specification, Rev. 1.0a, is provided "as is" with no warranties whatsoever including any warranty of merchantability, fitness for any particular purpose, or any other warranty otherwise arising out of any proposal, specification, or example.

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Universal Serial Bus (USB*) EHCI Specification

The Enhanced Host Controller Interface (EHCI) specification describes the register-level interface for a Host Controller for the Universal Serial Bus (USB) Revision 2.0. 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.

Implementation of the Enhanced Host Controller Interface specification requires a license from Intel. Adopters of the Enhanced Host Controller Interface specification for USB have signed the Enhanced Host Controller Interface specification for USB—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 Enhanced Host Controller Interface specification for USB.

Licensing of Revision 1.0 of the EHCI Specification allows the implementation of both discrete and integrated compliant EHCI host controllers. All versions of the specification prior to the Revision 1.0 level (0.95 and 0.96) are licensed to allow the implementation of compliant, discrete EHCI host controllers only.

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. The complete Revision 1.0 download includes two files: the specification and a summary of the changes between revision 0.96 and 1.0. All current development should be targeting this revision of the specification.

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Adopters can demonstrate compliance of their product(s) with the specification through the EHCI Compliance testing program provided by Intel. For details on the EHCI Compliance testing program, please visit . Please refer any questions about the specification or licensing program to EHCI Support by clicking on one of the following links:

Previous versions of the EHCI specification

(PDF 995KB)

(PDF 1.38MB)

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