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 controllers (i.e., ohci(4) or uhci(4)) handling USB 1.x de

vices. 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

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