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EHCI(4) 		     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 In-
     terface, which is used by USB 2.0 controllers.

     EHCI controllers are peculiar in that they can only handle the USB 2.0 pro-
     tocol.  This means that they normally  have  one  or  more  companion  con-
     trollers (i.e., ohci(4) or uhci(4)) handling USB 1.x devices.  Consequently
     each  USB	connector is electrically connected to two USB controllers.  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  dif-
     ferent 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.

FreeBSD 6.3			 March 20, 2005 			 EHCI(4)

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