123 lines
4.5 KiB
Groff
123 lines
4.5 KiB
Groff
.\" $NetBSD: usb.4,v 1.2 1998/07/12 20:56:23 augustss Exp $
|
|
.\" Copyright (c) 1998 The NetBSD Foundation, Inc.
|
|
.\" All rights reserved.
|
|
.\"
|
|
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the NetBSD
|
|
.\" Foundation, Inc. and its contributors.
|
|
.\" 4. Neither the name of The NetBSD Foundation nor the names of its
|
|
.\" contributors may be used to endorse or promote products derived
|
|
.\" from this software without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
|
|
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
|
|
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
|
|
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
.\" POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.Dd July 12, 1998
|
|
.Dt USB 4
|
|
.Os
|
|
.Sh NAME
|
|
.Nm usb
|
|
.Nd introduction to USB support
|
|
.Sh SYNOPSIS
|
|
.Cd "uhci* at pci? function?"
|
|
.Cd "ohci* at pci? function?"
|
|
.Cd "usb* at uhci?"
|
|
.Cd "usb* at ohci?"
|
|
.Cd "uhub* at usb?"
|
|
.Cd "uhub* at uhub? port ?"
|
|
.Cd "XX* at uhub? port ?"
|
|
.Pp
|
|
.Sh INTRODUCTION
|
|
.Nx
|
|
provides machine-independent bus support and
|
|
drivers for USB devices.
|
|
.Pp
|
|
The
|
|
.Nx
|
|
driver has three layers (like
|
|
.Xr scsi 4
|
|
and
|
|
.Xr pcmcia 4 ):
|
|
the controller, the bus, and the device layer.
|
|
The controller attaches to a physical bus (like
|
|
.Xr pci 4 ).
|
|
The USB bus attaches to the controller and the root hub attaches
|
|
to the controller. Further devices, which includes further hubs,
|
|
attach to other hubs. The attachment forms the same tree structure
|
|
as the physical USB device tree.
|
|
For each USB device there may be further drivers attached to it.
|
|
.Pp
|
|
The
|
|
.Cm uhub
|
|
device controls USB hubs and must always be present (since there
|
|
is at least a root hub in any USB system).
|
|
.Pp
|
|
.Sh INTRODUCTION TO USB
|
|
The USB is a 12Mb/s serial bus (1.5 Mb/s for low speed devices).
|
|
Each USB bus has a host controller that is the master of the bus;
|
|
all other devices on the bus only speak when spoken to.
|
|
.Pp
|
|
There can be up to 127 devices (apart from the host controller)
|
|
on a bus each with its own address. The addresses are assigned
|
|
dynamically by the host when the device is attached to the bus.
|
|
.Pp
|
|
Within each device there can be up to 16 endpoints. Each endpoint
|
|
is individually addressed and the addresses are static.
|
|
Each of these endpoints will communicate in one of four different modes:
|
|
control, isochronous, bulk, or interrupt. A device always has
|
|
at least one endpoint. This endpoint has address 0 and is a control
|
|
endpoint and is used to give commands to and extract basic data
|
|
such as descriptors from the device.
|
|
Each endpoint, except control endpoints, is unidirectional.
|
|
.Pp
|
|
The endpoints in a device are grouped into interfaces. An interface
|
|
is a logical unit within a device. E.g., a compound device with
|
|
both a keyboard and a trackball would present one interface for
|
|
each. An interface can sometimes be set into different modes,
|
|
called alternate settings, which affects how it operates.
|
|
Different alternate settings can have different endpoints
|
|
within it.
|
|
.Pp
|
|
A device may operate in different configurations. Depending on the
|
|
configuration the device may present different sets of endpoints
|
|
and interfaces.
|
|
.Pp
|
|
.\" The USB controller has a device that supports
|
|
.\" .Xr ioctl 2
|
|
.\" to manipulate it.
|
|
.Sh SEE ALSO
|
|
.Xr pci 4 ,
|
|
.Xr uaudio 4 ,
|
|
.Xr ugen 4 ,
|
|
.Xr uhid 4 ,
|
|
.Xr ukbd 4 ,
|
|
.Xr ulpt 4 ,
|
|
.Xr ums 4 ,
|
|
.Xr usbd 8 ,
|
|
.Xr usbdevs 8
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
driver
|
|
appeared in
|
|
.Nx 1.4 .
|