总线技术|接口技术
400万+工程师在用
华为|鸿蒙开发者日
直播报名
400万+工程师在用
华为|鸿蒙开发者日
直播报名

toread

12年用户 698经验值
私信 关注
[资料]

USB集线器规范

2008-6-17 10:37

本帖最后由 eehome 于 2013-1-5 10:06 编辑

<h2 class="r">USB<font color="#cc0033">集线器规范</font><br/></h2>
<p class="r">  </p>
<p class="MsoNormal" style="TEXT-INDENT: 21pt"><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">集线器规范包括两大基本部分:集线器转发中继器</span><span lang="EN-US">(Hub repeater)</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">和集线器控制器</span><span lang="EN-US">(Hub Controller)</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">。同时也描述了集线器的错误恢复,重启和挂起</span><span lang="EN-US">/</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">唤醒操作。最后简述集线器请求行为和集线器描述子。</span></p>
<p class="MsoNormal" style="TEXT-INDENT: 21pt"><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">集线器提供了</span><span lang="EN-US">USB</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">设备和主机之间的电子接口。集线器支持的主要的</span><span lang="EN-US">USB</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">功能有:</span></p>
<p class="MsoNormal" style="MARGIN-LEFT: 42.5pt; TEXT-INDENT: -21.25pt; tab-stops: list="list"  42.5pt; mso-list: l0="l0"  level1="level1"  lfo1"><span lang="EN-US" style="FONT-FAMILY: Wingdings; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings"><span style="mso-list: Ignore">?<span style="FONT: 7pt="7pt"  'Times New="New"  Roman'">            </span></span></span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">连接行为</span></p>
<p class="MsoNormal" style="MARGIN-LEFT: 42.25pt; TEXT-INDENT: -21.25pt; tab-stops: list="list"  42.25pt; mso-list: l0="l0"  level1="level1"  lfo1"><span lang="EN-US" style="FONT-FAMILY: Wingdings; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings"><span style="mso-list: Ignore">?<span style="FONT: 7pt="7pt"  'Times New="New"  Roman'">           </span></span></span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">电源管理</span></p>
<p class="MsoNormal" style="MARGIN-LEFT: 42.25pt; TEXT-INDENT: -21.25pt; tab-stops: list="list"  42.25pt; mso-list: l0="l0"  level1="level1"  lfo1"><span lang="EN-US" style="FONT-FAMILY: Wingdings; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings"><span style="mso-list: Ignore">?<span style="FONT: 7pt="7pt"  'Times New="New"  Roman'">           </span></span></span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">设备连接和未连接检测</span></p>
<p class="MsoNormal" style="MARGIN-LEFT: 42.25pt; TEXT-INDENT: -21.25pt; tab-stops: list="list"  42.25pt; mso-list: l0="l0"  level1="level1"  lfo1"><span lang="EN-US" style="FONT-FAMILY: Wingdings; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings"><span style="mso-list: Ignore">?<span style="FONT: 7pt="7pt"  'Times New="New"  Roman'">           </span></span></span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">总线错误检测和恢复</span></p>
<p class="MsoNormal" style="MARGIN-LEFT: 42.25pt; TEXT-INDENT: -21.25pt; tab-stops: list="list"  42.25pt; mso-list: l0="l0"  level1="level1"  lfo1"><span lang="EN-US" style="FONT-FAMILY: Wingdings; mso-fareast-font-family: Wingdings; mso-bidi-font-family: Wingdings"><span style="mso-list: Ignore">?<span style="FONT: 7pt="7pt"  'Times New="New"  Roman'">           </span></span></span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">高速和低速设备的支持。</span></p>
<p class="MsoBodyTextIndent"><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">集线器由集线器转发中继器和集线器控制器组成。集线器转发中继器负责连接方面的工作。它也支持像总线错误检测和恢复,连接和未连接检测这样的异常处理。集线器控制器提供主机到集线器的通讯机制。集线器特定的状态和控制命令允许主机配置集线器和监视与控制它的每个下行端口。</span></p>
<p class="MsoNormal" style="TEXT-INDENT: 21pt"><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">集线器根据它们是在传输包、唤醒信号或者是在空闲状态而表现出不同的连接行为。一、包信号连接。包信号连接分为上行连接和下行连接两种。上行连接是面向主机的。当某个使能的下行端口检测到</span><span lang="EN-US">SOP</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">时,就建立了仅到上行端口而不是任何其它下行端口的上行连接。下行连接是面向设备的。当集线器在上行端口上检测到</span><span lang="EN-US">SOP</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">时就建立到所有使能下行端口的连接。未处在使能状态的端口不能向下行方向传送。集线器还有没有任何连接的空闲状态。在空闲态时集线器所有端口都处在接收模式,等待下一个包的开始。二、唤醒连接。挂起的集线器将上行端口接收到的唤醒信号送到所有使能的下行端口。当挂起的集线器检测到来使局部挂起或使能下行端口的唤醒信号时,将反射唤醒信号到上行端口和包括自己在内的所有使能下行端口。唤醒信号不被反射到未使能的或挂起的下行端口。后面将有更详细的讨论。</span></p>
<p class="MsoNormal" style="TEXT-INDENT: 21pt"><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">集线器是主机和设备之间建立连接的极为重要的</span><span lang="EN-US">USB</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">部件。检测和防止任何连错误,尤其是能导致死锁的连接就显得非常重要。集线器必须在转发模式下处理连接错误。集线器必须也能检测和恢复发往集线器控制器的包。</span></p>
<p class="MsoNormal" style="TEXT-INDENT: 21pt"><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">每个集线器都有一个帧计时器。它的时间来自集线器的本地时钟,并通过主机发来的</span><span lang="EN-US">SOF</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">与主机同步。它提供被用来检测闲置</span><span lang="EN-US">(babbling)</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">设备和防止集线器被上行集线器设为无效的时间参考。集线器必须跟踪主机帧周期并能在即使丢失两个连续</span><span lang="EN-US">SOF</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">令牌的情况下仍然保持同步。在重启或唤醒后,帧计时器未同步。只要接收到两个连续的</span><span lang="EN-US">SOF</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">包,它就必须同步。</span></p>
<p class="MsoNormal" style="TEXT-INDENT: 21.25pt"><span lang="EN-US">EOF1</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">和</span><span lang="EN-US">EOF2</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">是由帧计时器产生的时刻。这些时刻用来确保设备和集线器不干扰来自主机的</span><span lang="EN-US">SOF</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">包的正确传输。这些时刻仅当帧计时器与</span><span lang="EN-US">SOF</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">同步时才有意义。图</span><span lang="EN-US">10-1</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">给出了严格的</span><span lang="EN-US">EOP</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">时刻。表</span><span lang="EN-US">10-1</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">总结了主机和集线器</span><span lang="EN-US">EOF</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">时刻。在</span><span lang="EN-US">EOF2</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">时刻,任何有上行连接的端口将被置为无效。集线器通过在上行集线器</span><span lang="EN-US">EOF2</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">之前发出</span><span lang="EN-US">EOP</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">来防止被设为未使能。</span><span lang="EN-US">(</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">如在</span><span lang="EN-US">EOF1</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">时刻</span><span lang="EN-US">)</span><span style="FONT-FAMILY: 宋体; mso-hansi-font-family: 'Times New="New"  Roman'; mso-ascii-font-family: 'Times New="New"  Roman'">。</span></p>
2AnbySSA.doc (470 KB)
(下载次数: 9, 2008-6-17 10:37 上传)
<br/>






回帖(3)

N Kan

2012-9-20 12:03:49
{:soso_e101:}

张工

2015-6-15 20:21:47
谢谢分享                                                         

王建航

2015-6-25 08:37:02
学习学习,谢谢分享!

更多回帖

打开APP