Intel Releases USB 2.0 Enhanced Host Controller Interface 1.0 Specification, EHCI Compliance-Testing Program

Spec Licensed Royalty-Free to Improve Compatibility

INTEL DEVELOPER FORUM, TOKYO, April 17, 2002 - In an effort to improve compatibility of the interface between USB 2.0 host controllers and software drivers, Intel has released the final version of its USB 2.0 Enhanced Host Controller Interface (EHCI) 1.0 specification. Intel is licensing the specification on a royalty-free basis.

Intel developed the EHCI specification with contributions from Agere Systems, Compaq Computer Corporation, Microsoft Corporation, NEC Corporation and Philips Semiconductors.

Complementing the EHCI specification is a compliance-testing program also announced today that measures implementation for spec conformance. EHCI compliance testing is conducted at no charge by Intel Labs, which will continue to provide the service until test software is released and a self-testing process is established. The first public Alpha release intended for a self-test program is expected in the second half of 2002.

During the development of USB 1.0, the existence of two versions of host controller interface specifications (UHCI and OHCI) made it more difficult for OS vendors to develop software support for multiple implementations of host controllers in the industry, according to Jason Ziller, Intel technology initiatives manager. For USB 2.0, Intel's goal was to develop one specification that the entire industry would use, increasing compatibility of the various implementations and making it easier to develop software support for all.

The specification defines an architecture that is fully compatible with USB 1.1 and 2.0 devices and hubs. It can even run USB 1.1 devices with existing USB 1.1 software drivers. The architecture is also highly optimized and therefore consumes minimum CPU overhead - less than the amount that a USB 1.1 UHCI host controller. In addition, existing USB 1.1 devices connect to USB 1.1 "companion" controllers, and therefore leave all of the high-speed bandwidth for USB 2.0 high-speed devices.

Licensing of the specification has been widespread, with more than 30 companies signed up to date. Licensees include major vendors of software and discrete and integrated host controllers.

"As one of the first implementers of Intel's EHCI specification, NEC has realized the tremendous benefit if offers to both the industry and consumers," said Hidetoshi Kosaka, general manager of NEC's Network System LSI Development Division. "The spec should help accelerate the adoption of USB 2.0, and lead to a better, more consistent consumer experience."

The first public version of the EHCI spec, designated revision 0.95, was released earlier, enabling NEC and other manufacturers to begin shipping discrete USB 2.0 host controllers.

The EHCI 1.0 specification, license agreement and information on the compliance-testing program can be found at http://developer.intel.com/technology/usb.

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