This document is an early draft of a guide to using <em>USB</em> Human Interface Devices with the
GNU/Linux operating system. It describes how Human Interface Device (HID) class <em>dev</em>ices
are handled, and how to program them, primarily focussing on user-space interfaces.
This document is matched to Linux kernel revision 2.4.19-pre7. Some of this information may
not work in exactly the same way on earlier or kernel revisions. Known differences to the 2.5.
series kernels are also included where appropriate.
Bus Hound is a powerful software product for capturing low level I/O from
-Supports IDE, SCSI, <em>USB</em>, 1394 and other <em>bus</em>es
-Supports all <em>dev</em>ices such as hard drives, DVD, mice, scanners, web cams
-Capture megabytes of I/O at a time
-View I/O in real time
-Supports every release of Windows 95, 98, Millennium, NT 4.0, 2000 and XP
-Run on an unlimited number of machines at the same time
-Capture any number of <em>dev</em>ices in parallel, regardless of <em>bus</em> type
-Fits on a diskette for easy installation and transportability
-Saves captured data on the PC for easy archival and e-mail access
-Simple <em>dev</em>ice selection from a graphical tree of <em>dev</em>ices and controllers
connected to the system
-Capture the system startup process
-Arrange captured data to user preferences such as the byte width per line
-View low level protocol including SCSI sense data and <em>USB</em> setup packets
-View microsecond resolution timing of each phase
-Drag and drop captured data to other products
-Pure software solution--no extra hardware or cables are needed
-View <em>dev</em>ice performance
<em>USB</em> in a Nutshell(<em>USB</em>概述)Making Sense of the <em>USB</em> StandardStarting out new with <em>USB</em> can be quite daunting. With the <em>USB</em> 2.0 specification at 650 pages one could easily beput off just by the sheer size of the standard. This is only the beginning of a long list of associated standards for<em>USB</em>. There are <em>USB</em> Class Standards such as the HID Class Specification which details the common operation of<em>dev</em>ices (keyboards, mice etc) falling under the HID (Human Interface Devices) Class - only another 97 pages. Ifyou are designing a <em>USB</em> Host, then you have three Host Controller Interface Standards to choose from. None ofthese are detailed in the <em>USB</em> 2.0 Spec.The good news is you don’t even need to bother reading the entire <em>USB</em> standard. Some chapters were churnedout by marketing, others aimed at the lower link layer normally taken care off by your <em>USB</em> controller IC and acouple aimed at host and hub <em>dev</em>elopers. Lets take a little journey through the various chapters of the <em>USB</em> 2.0specification and briefly introduce the key points.