The browser version you are using is not recommended for this site.
Please consider upgrading to the latest version of your browser by clicking one of the following links.

We are sorry, This PDF is available in download format only

Enhanced Host Controller Interface Specification: Addendum

Enhanced Host Controller Interface Specification: Addendum

The document defines energy-efficiency extensions for the USB 2.0 host controller based on the enhanced host controller interface (EHCI) specification.

● Hardware prefetching: The ability for host controller hardware to safely prefetch information from the asynchronous and periodic schedules beyond what was defined in previous EHCI implementations to improve system memory access behavior.
● Link power management: Defines the mechanisms by which software can discover and use link power management support offered in EHCI host controllers and USB devices.
● Per-port change events: Addresses an issue where system software is required to read and parse the port status registers for all enabled root ports upon every port change event (interrupt).
● Shorter periodic frame list: The ability for system software to convey and use a much shorter periodic frame list (32 frames) to better facilitate hardware prefetching.

Read the full Enhanced Host Controller Interface Specification Addendum.

Related Videos