Intel has released a draft specification for an interface that allows a Super-Speed USB host controller, which could be an expansion card or built into a PC, to communicate with the operating system.

The Extensible Host Controller Interface draft specification revision 0.9 was released Wednesday for Super-Speed USB, officially called USB 3.0. USB connectors are used to attach peripherals, such as printers and external hard drives, to a PC. USB 3.0, which has a data rate of 600 MB per second, is the fastest USB technology to date.

The Intel specification describes the registers and data structures used in communications between the system software and hardware. The specification is available under royalty free licensing terms to all members and contributors of the USB 3.0 Promoter Group, which is responsible for the development of the specification.

Intel is a member of the Promoter Group,along with partners Microsoft, Hewlett-Packard, NEC, and Texas Instruments. Non-member contributors include rival Advanced Micro Devices and graphics chipmaker Nvidia.

Intel in June tried to quell what it called "speculation" on tech sites that it was creating the USB 3.0 specification itself and that the standard uses technology from another industry technology group. The chipmaker said in its company blog that the misconceptions stemmed from Intel's development of the host controller specification, which Intel said is a separate effort by Intel.

"Think of the host controller spec as a 'Dummies Guide' to building a USB 3.0 compatible piece of silicon; it is not the USB 3.0 specification itself," Intel spokesman Nick Knupffer said.

Intel also said USB 3.0 does not borrow heavily from technology developed by the PCI Special Interests Group, which developed the PCI Express architecture used in attaching graphics cards and other components to motherboards. Intel contributed to both the USB and PCI Express specifications, but has not taken technology from the latter for the former, Knupffer said.

This article was edited on Aug. 14 to clarify the speed of USB 3.0.