NAME    [Toc]    [Back]

     ehci - USB Enhanced Host Controller driver

SYNOPSIS    [Toc]    [Back]

     ehci* at pci? dev ? function ?
     usb*  at ehci?

DESCRIPTION    [Toc]    [Back]

     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 controllers
  (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 different USB busses.

SEE ALSO    [Toc]    [Back]

     cardbus(4), ohci(4), pci(4), uhci(4), usb(4)

BUGS    [Toc]    [Back]

     The driver is not finished and is quite buggy.

     There  is  no support (yet) for hubs that are connected with
high speed upstream
 and low or full speed downstream (i.e., for  transaction translators).


     There  is  no  support  (yet)  for  interrupt or isochronous
transfers.

OpenBSD     3.6                        November      5,      2001