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EHCI(4)                  BSD Kernel Interfaces Manual                  EHCI(4)

NAME
     ehci -- USB Enhanced Host Controller driver

SYNOPSIS
     device ehci

DESCRIPTION
     The ehci driver provides support for the USB Enhanced Host Controller
     Interface, which is used by USB 2.0 controllers.

     EHCI controllers are peculiar in that they can only handle the USB 2.0
     protocol.  This means that they normally have one or more companion con-
     trollers (i.e., ohci(4) or uhci(4)) handling USB 1.x devices.  Conse-
     quently each USB connector is electrically connected to two USB con-
     trollers.  The handling of this is totally automatic, but can be noticed
     since USB 1.x and USB 2.0 devices plugged in to the same connector appear
     to connect to different USB busses.

SEE ALSO
     ohci(4), uhci(4), usb(4)

HISTORY
     The ehci device driver first appeared in FreeBSD 5.1.

BUGS
     The driver is not finished and is quite buggy.

     There is currently no support for isochronous transfers.

BSD                             March 20, 2005                             BSD