1998-07-13 00:56:23 +04:00
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.\" $NetBSD: usb.4,v 1.2 1998/07/12 20:56:23 augustss Exp $
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1998-07-12 23:51:55 +04:00
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.\" Copyright (c) 1998 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the NetBSD
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.\" Foundation, Inc. and its contributors.
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.\" 4. Neither the name of The NetBSD Foundation nor the names of its
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.\" contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd July 12, 1998
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.Dt USB 4
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.Os
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.Sh NAME
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.Nm usb
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.Nd introduction to USB support
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.Sh SYNOPSIS
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.Cd "uhci* at pci? function?"
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.Cd "ohci* at pci? function?"
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.Cd "usb* at uhci?"
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.Cd "usb* at ohci?"
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.Cd "uhub* at usb?"
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.Cd "uhub* at uhub? port ?"
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.Cd "XX* at uhub? port ?"
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.Pp
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.Sh INTRODUCTION
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.Nx
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provides machine-independent bus support and
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drivers for USB devices.
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.Pp
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The
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.Nx
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driver has three layers (like
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.Xr scsi 4
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and
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.Xr pcmcia 4 ):
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the controller, the bus, and the device layer.
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The controller attaches to a physical bus (like
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.Xr pci 4 ).
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The USB bus attaches to the controller and the root hub attaches
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to the controller. Further devices, which includes further hubs,
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attach to other hubs. The attachment forms the same tree structure
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as the physical USB device tree.
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For each USB device there may be further drivers attached to it.
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.Pp
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The
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.Cm uhub
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device controls USB hubs and must always be present (since there
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is at least a root hub in any USB system).
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.Pp
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.Sh INTRODUCTION TO USB
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The USB is a 12Mb/s serial bus (1.5 Mb/s for low speed devices).
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Each USB bus has a host controller that is the master of the bus;
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all other devices on the bus only speak when spoken to.
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.Pp
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There can be up to 127 devices (apart from the host controller)
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on a bus each with its own address. The addresses are assigned
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dynamically by the host when the device is attached to the bus.
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.Pp
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Within each device there can be up to 16 endpoints. Each endpoint
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is individually addressed and the addresses are static.
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Each of these endpoints will communicate in one of four different modes:
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control, isochronous, bulk, or interrupt. A device always has
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at least one endpoint. This endpoint has address 0 and is a control
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endpoint and is used to give commands to and extract basic data
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such as descriptors from the device.
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Each endpoint, except control endpoints, is unidirectional.
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.Pp
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The endpoints in a device are grouped into interfaces. An interface
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is a logical unit within a device. E.g., a compound device with
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both a keyboard and a trackball would present one interface for
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each. An interface can sometimes be set into different modes,
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called alternate settings, which affects how it operates.
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Different alternate settings can have different endpoints
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within it.
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.Pp
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A device may operate in different configurations. Depending on the
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configuration the device may present different sets of endpoints
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and interfaces.
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.Pp
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.\" The USB controller has a device that supports
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.\" .Xr ioctl 2
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.\" to manipulate it.
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.Sh SEE ALSO
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.Xr pci 4 ,
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.Xr uaudio 4 ,
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.Xr ugen 4 ,
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.Xr uhid 4 ,
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.Xr ukbd 4 ,
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.Xr ulpt 4 ,
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.Xr ums 4 ,
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1998-07-13 00:56:23 +04:00
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.Xr usbd 8 ,
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.Xr usbdevs 8
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1998-07-12 23:51:55 +04:00
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.Sh HISTORY
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The
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.Nm
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driver
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appeared in
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.Nx 1.4 .
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