Visual C++串口编程_C++_其他

<html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta charset="utf-8"> <meta name="generator" content="pdf2htmlEX"> <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"> <link rel="stylesheet" href="https://static.pudn.com/base/css/base.min.css"> <link rel="stylesheet" href="https://static.pudn.com/base/css/fancy.min.css"> <link rel="stylesheet" href="https://static.pudn.com/prod/directory_preview_static/62574f3fbd8c6f2306bf6044/raw.css"> <script src="https://static.pudn.com/base/js/compatibility.min.js"></script> <script src="https://static.pudn.com/base/js/pdf2htmlEX.min.js"></script> <script> try{ pdf2htmlEX.defaultViewer = new pdf2htmlEX.Viewer({}); }catch(e){} </script> <title></title> </head> <body> <div id="sidebar" style="display: none"> <div id="outline"> </div> </div> <div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62574f3fbd8c6f2306bf6044/bg1.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls0 ws0">引言<span class="ff2 sc1 ls1"> </span></div><div class="t m0 x2 h3 y2 ff3 fs1 fc0 sc1 ls1 ws0">·<span class="ff1">串口通信是<span class="_ _0"> </span></span><span class="ls2">Windows<span class="_"> </span></span><span class="ff1">应用软件开发的重要环节，除了普通的通信软件外，还在工业控制领域有广泛的用</span></div><div class="t m0 x2 h3 y3 ff1 fs1 fc0 sc1 ls1 ws0">途，因此掌握串口编程是每个程序员的必备技巧。<span class="ff3"> </span></div><div class="t m0 x2 h3 y4 ff3 fs1 fc0 sc1 ls1 ws0">·<span class="ff1">无庸讳言，<span class="_ _1"></span>目前网上有不少介绍串口通信的文章和代码，<span class="_ _1"></span>但对广大读者而言，<span class="_ _1"></span>缺少入门的、<span class="_ _1"></span>系统的介绍串</span></div><div class="t m0 x2 h3 y5 ff1 fs1 fc0 sc1 ls1 ws0">口编程的教程，因此小编组织了这个教程，它将填补这方面的空白。<span class="ff3"> </span></div><div class="t m0 x2 h4 y6 ff4 fs1 fc1 sc1 ls1 ws0"> </div><div class="t m0 x2 h4 y7 ff1 fs1 fc1 sc2 ls3 ws0">深入浅出<span class="_ _0"> </span><span class="ff4 sc1 ls4 ws1">Visual C++</span><span class="ls1">串口编程<span class="ff4 sc1"> <span class="_ _0"> </span><span class="ff3 fc0"> </span></span></span></div><div class="t m0 x2 h3 y8 ff1 fs1 fc0 sc1 ls5 ws0"> <span class="ff3 ls6">RS-232C<span class="_"> </span></span><span class="ls1">接口，<span class="ff3 ls2">1970<span class="_ _0"> </span></span>年由美国电子工业协会联合贝尔系统、调制解调器厂家及计算机终端生产厂家</span></div><div class="t m0 x2 h3 y9 ff1 fs1 fc0 sc1 ls1 ws0">共同制定，<span class="_ _2"></span>全名是<span class="ff3">"</span>数据终端设备<span class="_ _2"></span>（<span class="ff3 ls7">DTE</span>）<span class="_ _2"></span>和数据通讯设备<span class="_ _2"></span>（<span class="ff3 ls7">DCE</span>）<span class="_ _2"></span>之间串行二进制数据交换接口技术标准</div><div class="t m0 x2 h3 ya ff3 fs1 fc0 sc1 ls1 ws0">"<span class="ff1">。<span class="_ _3"></span>本期教程将对<span class="_ _0"> </span><span class="ff3">DOS<span class="_ _0"> </span></span>平台的串口编程，<span class="_ _3"></span>及<span class="_ _0"> </span><span class="ff3 ls2">Windo<span class="_ _4"></span>ws<span class="_ _0"> </span></span>平台下基于<span class="_ _0"> </span><span class="ff3 ls8">API</span>、<span class="_ _3"></span>控件和第三方类的串口编程进行介</span></div><div class="t m0 x2 h3 yb ff1 fs1 fc0 sc1 ls1 ws0">绍。<span class="ff3"> </span></div><div class="t m0 x3 h2 yc ff1 fs0 fc0 sc0 ls0 ws0">深入浅出<span class="_ _5"> </span><span class="ff2 sc1 ls9">VC++</span>串口编程之基本概念<span class="ff2 sc1 ls1"> </span></div><div class="t m0 x4 h3 yd ff1 fs1 fc0 sc1 ls5 ws0"> 在<span class="_ _6"></span><span class="ff3 ls8">PC<span class="_ _0"> </span><span class="ff1 ls1">机的主板上，有一种类型的接口可能为我们所忽视，那就是<span class="_ _0"> </span></span><span class="ls6">RS-232C<span class="_"> </span><span class="ff1 ls1">串行接口，在微软的</span></span></span></div><div class="t m0 x5 h3 ye ff3 fs1 fc0 sc1 ls2 ws0">Windows<span class="_"> </span><span class="ff1 ls1">系统中称其为<span class="_ _0"> </span><span class="ff3">COM</span>。我们可以通过设备管理器来查看<span class="_ _0"> </span><span class="ff3">COM<span class="_ _0"> </span></span>的硬件参数设置，如图<span class="_ _0"> </span><span class="ff3">1</span>。<span class="ff3"> </span></span></div><div class="t m0 x6 h5 yf ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x7 h3 y10 ff1 fs1 fc0 sc1 ls1 ws0">图<span class="_ _0"> </span><span class="ff3 ls2">1 <span class="_ _0"> </span></span>在<span class="_ _7"> </span><span class="ff3 lsa">Windows<span class="_ _7"> </span></span>上查看<span class="_ _0"> </span><span class="ff3 lsb">PC<span class="_ _0"> </span></span>串口设置<span class="ff3"> </span></div><div class="t m0 x2 h5 y11 ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x2 h3 y12 ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>迄今为止，几乎每一台<span class="_ _8"> </span><span class="ff3 ls8">PC<span class="_"> </span></span>都包含<span class="_ _8"> </span><span class="ff3">COM</span>。本质而言，<span class="ff3">COM<span class="_"> </span></span>是<span class="_ _8"> </span><span class="ff3 ls8">PC<span class="_"> </span></span>为和外界通信所提供的一种串行数</div><div class="t m0 x2 h3 y13 ff1 fs1 fc0 sc1 ls1 ws0">据传输的接口。<span class="_ _3"></span>作为一种物理通信的途径和设备，<span class="_ _2"></span>它和目前风靡的另一种串行接口<span class="ff5">――<span class="ff3 ls6">USB<span class="_"> </span></span></span>所提供的功能</div><div class="t m0 x2 h3 y14 ff1 fs1 fc0 sc1 ls1 ws0">是一致的。不过<span class="_"> </span><span class="ff3 ls6">RS-232C<span class="_ _9"> </span></span>显然已经开始被后起之秀<span class="_"> </span><span class="ff3 ls6">USB<span class="_ _9"> </span></span>赶超，因为<span class="_"> </span><span class="ff3 ls6">USB<span class="_ _9"> </span></span>的传输速率已经远远超过了</div><div class="t m0 x2 h3 y15 ff3 fs1 fc0 sc1 ls6 ws0">RS-232C<span class="ff1 ls1">。<span class="ff3"> </span></span></div><div class="t m0 x2 h3 y16 ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>尽管如此，<span class="ff3 ls6">RS-232C<span class="_ _a"> </span></span>仍然具有非常广泛的应用，在相对长的一段时间里，难以被<span class="_ _a"> </span><span class="ff3 ls6">USB<span class="_ _a"> </span></span>等接口取代。</div><div class="t m0 x2 h3 y17 ff3 fs1 fc0 sc1 ls6 ws0">RS-232C<span class="_ _a"> </span><span class="ff1 ls1">接口（又称<span class="_ _a"> </span></span><span class="ls8 ws2">EIA RS-232C</span><span class="ff1 ls1">），</span><span class="ls2">1970<span class="_ _a"> </span><span class="ff1 ls1">年由美国电子工业协会（</span><span class="ls9">EIA<span class="ff1 ls1">）联合贝尔系统、调制解调器</span></span></span></div></div><div class="pi" data-data='{"ctm":[1.611639,0.000000,0.000000,1.611639,0.000000,0.000000]}'></div></div> </body> </html>

<div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62574f3fbd8c6f2306bf6044/bg2.jpg"><div class="t m0 x2 h3 y18 ff1 fs1 fc0 sc1 ls1 ws0">厂家及计算机终端生产厂家共同制定，<span class="_ _2"></span>全名是<span class="ff3">"</span>数据终端设备<span class="_ _2"></span>（<span class="ff3 ls7">DTE</span>）<span class="_ _2"></span>和数据通讯设备<span class="_ _2"></span>（<span class="ff3 ls7">DCE</span>）<span class="_ _2"></span>之间串行二</div><div class="t m0 x2 h3 y19 ff1 fs1 fc0 sc1 ls1 ws0">进制数据交换接口技术标准<span class="ff3">"</span>。<span class="ff3"> </span></div><div class="t m0 x2 h3 y1a ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>本文将对这一接口进行硬件原理的介绍，<span class="_ _2"></span>随后我们将逐章学习<span class="_ _0"> </span><span class="ff3">DOS<span class="_"> </span></span>平台的串口编程，<span class="_ _2"></span>及<span class="_ _0"> </span><span class="ff3 lsc">Windo<span class="_ _4"></span>ws<span class="_ _7"> </span></span>平</div><div class="t m0 x2 h3 y1b ff1 fs1 fc0 sc1 ls1 ws0">台下基于<span class="_ _7"> </span><span class="ff3 ls8">API<span class="_ _4"></span></span>、控件和第三方类的串口编程，最后本文将给出一个综合实例。<span class="ff3"> </span></div><div class="t m0 x2 h3 y1c ff1 fs1 fc0 sc1 ls5 ws0"> <span class="ff3 ls1"> </span></div><div class="t m0 x2 h3 y1d ff1 fs1 fc0 sc0 ls3 ws0">硬件原理<span class="ff3 sc1 ls1"> </span></div><div class="t m0 x2 h3 y1e ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>众所周知，<span class="ff3 ls6">CPU<span class="_ _a"> </span></span>与存储芯片和<span class="_ _a"> </span><span class="ff3 lsd">I/<span class="_ _1"></span>O<span class="_ _a"> </span><span class="ff1 ls1">芯片的通信是并行的（并行传输的最大位数依赖于<span class="_ _8"> </span></span><span class="ls6">CPU<span class="_ _a"> </span><span class="ff1 ls1">的字长、</span></span></span></div><div class="t m0 x2 h3 y1f ff1 fs1 fc0 sc1 ls1 ws0">数据总线的宽度），一种叫做<span class="_ _7"> </span><span class="ff3 lse">UART<span class="_ _4"></span></span>（通用异步收发器，<span class="ff3 lsf ws3">Universal Async<span class="_ _4"></span>hronous Receiver/Transmitter</span>）</div><div class="t m0 x2 h3 y20 ff1 fs1 fc0 sc1 ls1 ws0">的芯片提供了并行数据传输和<span class="_ _b"> </span><span class="ff3 ls10">RS-232C<span class="_ _a"> </span></span>串行数据传输方式的转换。这样的设备通常有如图<span class="_ _b"> </span><span class="ff3">2<span class="_ _b"> </span></span>所<span class="_ _4"></span>示的管脚</div><div class="t m0 x2 h3 y21 ff1 fs1 fc0 sc1 ls1 ws0">分布，<span class="_ _2"></span>当其向外传输数据时，<span class="_ _2"></span><span class="ff3 ls6">CPU<span class="_"> </span><span class="ff1 ls1">并行的将数据写入这类芯片的寄存器，<span class="_ _2"></span><span class="ff3 lse">UART<span class="_"> </span><span class="ff1 ls1">再<span class="_ _1"></span>将寄存器中的数据一位</span></span></span></span></div><div class="t m0 x2 h3 y22 ff1 fs1 fc0 sc1 ls1 ws0">一位地移动并向外传输；当外界向其传输数据时，<span class="ff3 ls6">UART<span class="_ _5"> </span></span>一位一位地接收数据，并将其移位组合为并行数</div><div class="t m0 x2 h3 y23 ff1 fs1 fc0 sc1 ls1 ws0">据，<span class="_ _2"></span><span class="ff3 ls6">CPU<span class="_"> </span><span class="ff1 ls1">再并行地读取这些数据。<span class="_ _2"></span>实际上，<span class="_ _2"></span>由于<span class="_ _0"> </span><span class="ff3 lse">UART<span class="_"> </span></span>芯片一般以<span class="_ _7"> </span><span class="ff3 ls11">TTL/CMOS<span class="_"> </span></span>电平工作，<span class="_ _2"></span>在<span class="_ _0"> </span><span class="ff3 ls6">UART<span class="_"> </span></span>连接</span></span></div><div class="t m0 x2 h3 y24 ff1 fs1 fc0 sc1 ls1 ws0">接口之前，<span class="_ _3"></span>还要经过一个<span class="_ _7"> </span><span class="ff3 ls11">TTL/CMOS<span class="_ _7"> </span></span>和<span class="_ _0"> </span><span class="ff3 ls12">RS-232<span class="_ _4"></span>C<span class="_"> </span></span>电平的转换。<span class="_ _c"></span><span class="ff3 ls13">RS-232C<span class="_"> </span><span class="ff1 ls1">规定了其标准的电气特性，<span class="_ _c"></span>逻辑</span></span></div><div class="t m0 x2 h3 y25 ff3 fs1 fc0 sc1 ls1 ws0">1<span class="_ _7"> </span><span class="ff1">对应的电压必<span class="_ _4"></span>须在</span><span class="lsc">-5</span><span class="ff1">～</span><span class="ls14">-15V<span class="_ _7"> </span></span><span class="ff1">之间；逻辑<span class="_ _0"> </span></span>0<span class="_"> </span><span class="ff1">对应的的电压必须在</span><span class="ls15">+5</span><span class="ff1">～</span><span class="ls2">+15V<span class="_"> </span></span><span class="ff1">之间。</span> </div><div class="t m0 x8 h5 y26 ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x9 h3 y27 ff1 fs1 fc0 sc1 ls1 ws0">图<span class="_ _7"> </span><span class="ff3 ls12 ws4">2 UART<span class="_"> </span></span>并<span class="ff3">/</span>串转换<span class="ff3"> </span></div><div class="t m0 xa h5 y28 ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 xb h3 y29 ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>一个常见的<span class="_ _7"> </span><span class="ff3 ls14">TT<span class="_ _4"></span>L/CMOS<span class="_ _7"> </span></span>和<span class="_ _0"> </span><span class="ff3 ls6">RS-232C<span class="_"> </span></span>电平转换芯片如图<span class="_ _0"> </span><span class="ff3">3</span>。<span class="ff3"> </span></div><div class="t m0 xc h5 y2a ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 xa h5 y2b ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 xa h5 y2c ff3 fs1 fc0 sc1 ls1 ws0"> </div></div><div class="pi" data-data='{"ctm":[1.611639,0.000000,0.000000,1.611639,0.000000,0.000000]}'></div></div>

<div id="pf3" class="pf w0 h0" data-page-no="3"><div class="pc pc3 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62574f3fbd8c6f2306bf6044/bg3.jpg"><div class="t m0 xd h3 y18 ff1 fs1 fc0 sc1 ls5 ws0"> <span class="ff3 ls6">RS-232C<span class="_"> </span></span><span class="ls1">通常以两类接插件与外界相连，分别称为<span class="_ _7"> </span><span class="ff3 ls6">DB9<span class="_"> </span></span>和<span class="_ _7"> </span><span class="ff3 ls16">DB25</span>，如图<span class="_ _0"> </span><span class="ff3">4<span class="_"> </span></span>所示。<span class="ff3"> </span></span></div><div class="t m0 xe h5 y2d ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 xf h3 y2e ff1 fs1 fc0 sc1 ls1 ws0">图<span class="_ _7"> </span><span class="ff3 ls16 ws5">4 DB<span class="_ _4"></span>9<span class="_"> </span></span>和<span class="_ _7"> </span><span class="ff3 ls2">DB25 </span></div><div class="t m0 xa h5 y2f ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x10 h3 y30 ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>而接插件中各个针的定义则如表<span class="_ _7"> </span><span class="ff3">1</span>：<span class="ff3"> </span></div><div class="t m0 x11 h3 y31 ff1 fs1 fc0 sc1 ls5 ws0"> 表<span class="_ _6"></span><span class="ff3 ls16 ws5">1 DB9<span class="_"> </span><span class="ff1 ls1 ws0">和<span class="_ _7"> </span><span class="ff3 ls6">DB25<span class="_"> </span></span>引脚定义<span class="ff3"> </span></span></span></div><div class="t m0 x12 h5 y32 ff3 fs1 fc0 sc1 ls12 ws6">DB9 <span class="_ _d"> </span>DB25 </div><div class="t m0 x13 h3 y33 ff1 fs1 fc0 sc1 ls1 ws0">针号<span class="ff3 ls17"> <span class="_ _e"> </span></span>功能说明<span class="ff3 ls17"> <span class="_ _f"> </span></span>缩写<span class="ff3"> <span class="_ _10"> </span></span>针号<span class="ff3"> <span class="_ _11"> </span></span>功能说明<span class="ff3 ls17"> <span class="_ _12"> </span></span>缩写<span class="ff3"> </span></div><div class="t m0 x14 h5 y34 ff3 fs1 fc0 sc1 ls2 ws7">1 </div><div class="t m0 x15 h3 y35 ff1 fs1 fc0 sc1 ls1 ws0">数据载波检测<span class="ff3"> </span></div><div class="t m0 x16 h5 y34 ff3 fs1 fc0 sc1 ls18 ws8">DCD 8 <span class="_ _13"></span> </div><div class="t m0 x17 h3 y35 ff1 fs1 fc0 sc1 ls1 ws0">数据载波检测<span class="ff3 ls17"> </span></div><div class="t m0 x18 h5 y34 ff3 fs1 fc0 sc1 ls7 ws0">DCD </div><div class="t m0 x14 h5 y36 ff3 fs1 fc0 sc1 ls2 ws7">2 </div><div class="t m0 x19 h3 y37 ff1 fs1 fc0 sc1 ls1 ws0">接收数据<span class="ff3 ls17"> </span></div><div class="t m0 x16 h5 y36 ff3 fs1 fc0 sc1 ls12 ws9">RXD 3 <span class="_ _13"></span> </div><div class="t m0 x1a h3 y37 ff1 fs1 fc0 sc1 ls1 ws0">接收数据<span class="ff3"> </span></div><div class="t m0 x18 h5 y36 ff3 fs1 fc0 sc1 lse ws0">RXD </div><div class="t m0 x14 h5 y38 ff3 fs1 fc0 sc1 ls2 ws7">3 </div><div class="t m0 x19 h3 y39 ff1 fs1 fc0 sc1 ls1 ws0">发送数据<span class="ff3"> </span></div><div class="t m0 x1b h5 y38 ff3 fs1 fc0 sc1 ls19 wsa">TXD 2<span class="_ _2"></span> <span class="_ _14"></span> </div><div class="t m0 x1a h3 y39 ff1 fs1 fc0 sc1 ls1 ws0">发送数据<span class="ff3 ls17"> </span></div><div class="t m0 x1c h5 y38 ff3 fs1 fc0 sc1 ls19 ws0">TXD </div><div class="t m0 x14 h5 y3a ff3 fs1 fc0 sc1 ls2 ws7">4 </div><div class="t m0 x15 h3 y3b ff1 fs1 fc0 sc1 ls1 ws0">数据终端准备<span class="ff3 ls17"> </span></div><div class="t m0 x16 h5 y3a ff3 fs1 fc0 sc1 ls16 wsb">DTR 20 </div><div class="t m0 x17 h3 y3b ff1 fs1 fc0 sc1 ls1 ws0">数据终端准备<span class="ff3 ls17"> </span></div><div class="t m0 x18 h5 y3a ff3 fs1 fc0 sc1 ls7 ws0">DTR </div><div class="t m0 x14 h5 y3c ff3 fs1 fc0 sc1 ls2 ws7">5 </div><div class="t m0 x1d h3 y3d ff1 fs1 fc0 sc1 ls1 ws0">信号地<span class="ff3 ls17"> </span></div><div class="t m0 x16 h5 y3c ff3 fs1 fc0 sc1 lse wsc">GND 7 <span class="_ _15"></span> </div><div class="t m0 x1e h3 y3d ff1 fs1 fc0 sc1 ls1 ws0">信号地<span class="ff3 ls17"> </span></div><div class="t m0 x18 h5 y3c ff3 fs1 fc0 sc1 lsf ws0">GND </div><div class="t m0 x14 h5 y3e ff3 fs1 fc0 sc1 ls2 ws7">6 </div><div class="t m0 xb h3 y3f ff1 fs1 fc0 sc1 ls1 ws0">数据设备准备好<span class="ff3"> </span></div><div class="t m0 x16 h5 y3e ff3 fs1 fc0 sc1 ls12 ws9">DSR 6 <span class="_ _14"></span> </div><div class="t m0 x1f h3 y3f ff1 fs1 fc0 sc1 ls1 ws0">数据准备好<span class="ff3"> </span></div><div class="t m0 x18 h5 y3e ff3 fs1 fc0 sc1 lse ws0">DSR </div><div class="t m0 x14 h5 y40 ff3 fs1 fc0 sc1 ls2 ws7">7 </div><div class="t m0 x19 h3 y41 ff1 fs1 fc0 sc1 ls1 ws0">请求发送<span class="ff3"> </span></div><div class="t m0 x1b h5 y40 ff3 fs1 fc0 sc1 ls13 wsd">RTS 4 <span class="_ _14"></span> </div><div class="t m0 x1a h3 y41 ff1 fs1 fc0 sc1 ls1 ws0">请求发送<span class="ff3 ls17"> </span></div><div class="t m0 x1c h5 y40 ff3 fs1 fc0 sc1 ls6 ws0">RTS </div><div class="t m0 x14 h5 y42 ff3 fs1 fc0 sc1 ls2 ws7">8 </div><div class="t m0 x19 h3 y43 ff1 fs1 fc0 sc1 ls1 ws0">清除发送<span class="ff3 ls17"> </span></div><div class="t m0 x1b h5 y42 ff3 fs1 fc0 sc1 ls13 wsd">CTS 5 <span class="_ _14"></span> </div><div class="t m0 x1a h3 y43 ff1 fs1 fc0 sc1 ls1 ws0">清除发送<span class="ff3"> </span></div><div class="t m0 x1c h5 y42 ff3 fs1 fc0 sc1 ls6 ws0">CTS </div><div class="t m0 x14 h5 y44 ff3 fs1 fc0 sc1 ls2 ws7">9 </div><div class="t m0 x19 h3 y45 ff1 fs1 fc0 sc1 ls1 ws0">振铃指示<span class="ff3"> </span></div><div class="t m0 x20 h5 y44 ff3 fs1 fc0 sc1 ls18 wse">DELL 22 </div><div class="t m0 x1a h3 y45 ff1 fs1 fc0 sc1 ls1 ws0">振铃指示<span class="ff3"> </span></div><div class="t m0 x21 h5 y44 ff3 fs1 fc0 sc1 ls7 ws0">DELL </div><div class="t m0 x2 h3 y46 ff1 fs1 fc0 sc1 ls5 ws0"> <span class="ff3 ls6">RS-232C<span class="_"> </span></span><span class="ls1">定义为数据通信设备（<span class="ff3 ls7">DCE</span>）和数据终端设备（<span class="ff3 ls7">DTE</span>）之间的互连，实现上，到现在为止，</span></div><div class="t m0 x2 h3 y47 ff1 fs1 fc0 sc1 ls1 ws0">究竟一个设备属于<span class="_ _7"> </span><span class="ff3 ls7">DC<span class="_ _4"></span>E<span class="_"> </span></span>还是属于<span class="_ _7"> </span><span class="ff3 ls7">DTE<span class="_"> </span></span>已经没有明显的界限，<span class="_ _3"></span><span class="ff3 ls8">PC<span class="_"> </span><span class="ff1 ls1">即可作为<span class="_ _7"> </span></span><span class="ls7">DCE<span class="ff1 ls1a">，又<span class="_ _16"></span>可<span class="_ _16"></span>作<span class="_ _4"></span>为<span class="_ _a"> </span></span>DT<span class="_ _4"></span>E<span class="ff1 ls1">。<span class="_ _2"></span>两串口</span></span></span></div><div class="t m0 x2 h3 y48 ff1 fs1 fc0 sc1 ls1 ws0">互连，连接方法主要有二：<span class="ff3"> </span></div><div class="t m0 x2 h3 y49 ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>一种方法是，数据的发送和接收由软件控制，<span class="_ _2"></span>不进行硬件握手，其连接方法如图<span class="_ _7"> </span><span class="ff3">5</span>（最常用<span class="_ _7"> </span><span class="ff3 ls1b">DB9<span class="_"> </span></span>连接</div><div class="t m0 x2 h3 y4a ff1 fs1 fc0 sc1 ls1 ws0">示意）和表<span class="_ _7"> </span><span class="ff3">2</span>（<span class="_ _4"></span><span class="ff3 ls6">DB9</span>、<span class="ff3 ls16">DB25<span class="_"> </span></span>三线连接表），真正需要互相连接的是<span class="_ _7"> </span><span class="ff3 ls1c">RXD</span>、<span class="ff3 ls19">TXD<span class="_ _7"> </span></span>和<span class="_ _7"> </span><span class="ff3">GND<span class="_ _4"></span></span>；<span class="ff3"> </span></div><div class="t m0 x22 h5 y4b ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x23 h3 y4c ff1 fs1 fc0 sc1 ls1 ws0">图<span class="_ _7"> </span><span class="ff3 ls2">5 <span class="_"> </span></span>无硬件握手时两串口连接<span class="ff3"> </span></div><div class="t m0 xa h5 y4d ff3 fs1 fc0 sc1 ls1 ws0"> </div></div><div class="pi" data-data='{"ctm":[1.611639,0.000000,0.000000,1.611639,0.000000,0.000000]}'></div></div>

<div id="pf4" class="pf w0 h0" data-page-no="4"><div class="pc pc4 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62574f3fbd8c6f2306bf6044/bg4.jpg"><div class="t m0 x24 h3 y18 ff1 fs1 fc0 sc1 ls5 ws0"> 表<span class="_ _6"></span><span class="ff3 ls1d wsf">2 DB9<span class="ff1 ls1 ws0">、<span class="ff3 ls6">DB25<span class="_"> </span></span>三线连接<span class="ff3"> </span></span></span></div><div class="t m0 x25 h3 y4e ff3 fs1 fc0 sc1 ls1 ws0">9<span class="_ _7"> </span><span class="ff1">针－<span class="_ _4"></span></span>9<span class="_ _7"> </span><span class="ff1">针</span><span class="ls1e"> 5<span class="_ _17"></span><span class="ff1 ls1">针－<span class="ff3 ls1f">25<span class="_ _7"> </span></span>针<span class="ff3 ls2 ws10"> 2 <span class="_ _18"></span>9<span class="_ _7"> </span><span class="ff1 ls1 ws0">针－<span class="ff3 ls1f">25<span class="_"> </span></span>针<span class="ff3"> </span></span></span></span></span></div><div class="t m0 x26 h5 y4f ff3 fs1 fc0 sc1 ls2 ws7">2 <span class="_ _19"> </span>3 <span class="_ _1a"> </span>3 <span class="_ _1b"> </span>2 <span class="_ _1c"> </span>2 <span class="_ _1d"> </span>2 </div><div class="t m0 x26 h5 y50 ff3 fs1 fc0 sc1 ls2 ws7">3 <span class="_ _19"> </span>2 <span class="_ _1a"> </span>2 <span class="_ _1b"> </span>3 <span class="_ _1c"> </span>3 <span class="_ _1d"> </span>3 </div><div class="t m0 x26 h5 y51 ff3 fs1 fc0 sc1 ls2 ws7">5 <span class="_ _19"> </span>5 <span class="_ _1a"> </span>7 <span class="_ _1b"> </span>7 <span class="_ _1c"> </span>5 <span class="_ _1d"> </span>7 </div><div class="t m0 x2 h5 y52 ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x2 h3 y53 ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>软件握手又称为<span class="_ _0"> </span><span class="ff3 ls20">XON/XO<span class="_ _4"></span>FF</span>，通常以<span class="_ _0"> </span><span class="ff3 ls21">CTRL-S</span>（<span class="ff3 ls12">0x13</span>）和<span class="_ _0"> </span><span class="ff3 ls21">CT<span class="_ _4"></span>RL-Q</span>（<span class="ff3 ls12">0x11</span>）两个字符来实现流控制。</div><div class="t m0 x2 h3 y54 ff1 fs1 fc0 sc1 ls1 ws0">前者用于请求对方暂停发送，后者用于清除暂停传送的请求，继续发送数据。<span class="ff3"> </span></div><div class="t m0 x2 h3 y55 ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>另一种方法是，数据的发送和接收由硬件控制，<span class="_ _2"></span>进行硬件握手，其连接方法如图<span class="_ _7"> </span><span class="ff3">6</span>（最常用<span class="_ _7"> </span><span class="ff3 ls1b">DB9<span class="_"> </span></span>连接</div><div class="t m0 x2 h3 y56 ff1 fs1 fc0 sc1 ls1 ws0">示意），需要连接的信号除<span class="_ _7"> </span><span class="ff3 ls6">RXD</span>、<span class="ff3 ls19">TXD<span class="_ _0"> </span></span>和<span class="_ _0"> </span><span class="ff3">GND<span class="_"> </span></span>外，还包括<span class="_ _7"> </span><span class="ff3 ls7">DTR</span>、<span class="ff3 ls6">DSR</span>、<span class="ff3 ls7">RT<span class="_ _4"></span>S<span class="_"> </span></span>和<span class="_ _7"> </span><span class="ff3 ls7">CTS</span>。<span class="ff3"> </span></div><div class="t m0 x2 h3 y57 ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>硬件握手依赖于<span class="_ _7"> </span><span class="ff3 ls7">RT<span class="_ _4"></span>S<span class="_"> </span></span>和<span class="_ _7"> </span><span class="ff3 ls7">CTS<span class="_"> </span></span>信号，当发送设备欲发送数据时，将<span class="_ _7"> </span><span class="ff3 ls7">RTS<span class="_"> </span></span>信号置为有效表示请求发送，</div><div class="t m0 x2 h3 y58 ff1 fs1 fc0 sc1 ls1 ws0">接收设备准备好后，置<span class="_ _7"> </span><span class="ff3 ls7">CT<span class="_ _4"></span>S<span class="_"> </span></span>信号有效，接着发送设备通过信号线<span class="_ _7"> </span><span class="ff3 ls19">TXD<span class="_ _7"> </span></span>开始发送串行数据。<span class="ff3"> </span></div><div class="t m0 x2 h3 y59 ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>这里我们联想开来，<span class="_ _6"></span><span class="ff3 ls22">RT<span class="_ _4"></span>S/CTS<span class="_"> </span><span class="ff1 ls1">模式在许多领域里都出现过。<span class="_ _6"></span>回忆一下<span class="_ _7"> </span><span class="ff3 ls23 ws11">IEEE 802.1<span class="_ _4"></span>1<span class="_"> </span></span>无线局域网协议标</span></span></div><div class="t m0 x2 h3 y5a ff1 fs1 fc0 sc1 ls1 ws0">准，在其<span class="_ _0"> </span><span class="ff3">MAC<span class="_"> </span></span>协议中就使用了<span class="_ _8"> </span><span class="ff3 ls22">RTS/CTS<span class="_ _4"></span></span>，<span class="ff3 ls23">RTS/CTS<span class="_"> </span></span>抽象开来就是一种请求<span class="ff3">/</span>应答。笔者曾经在拙作中多</div><div class="t m0 x2 h3 y5b ff1 fs1 fc0 sc1 ls1 ws0">次以实例论证计算机领域里许多知识的相通性，这又是一个明证。<span class="ff3"> </span></div><div class="t m0 x22 h5 y5c ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x23 h3 y5d ff1 fs1 fc0 sc1 ls1 ws0">图<span class="_ _7"> </span><span class="ff3 ls2">6 <span class="_"> </span></span>有硬件握手时两串口连接<span class="ff3"> </span></div><div class="t m0 xa h5 y5e ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x2 h3 y5f ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>实际上，目前我们经常使用的是方法一，即只连接<span class="_ _7"> </span><span class="ff3 ls6">RXD</span>、<span class="ff3 ls19">TXD<span class="_ _0"> </span></span>和<span class="_ _0"> </span><span class="ff3">GND</span>，简单灵活。另外，串口之间</div><div class="t m0 x27 h3 y60 ff1 fs1 fc0 sc1 ls1 ws0">互连还有诸多途径，如图<span class="_ _7"> </span><span class="ff3">7<span class="_"> </span></span>所示。<span class="ff3"> </span></div><div class="t m0 x28 h5 y61 ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 xa h5 y62 ff3 fs1 fc0 sc1 ls1 ws0"> </div></div><div class="pi" data-data='{"ctm":[1.611639,0.000000,0.000000,1.611639,0.000000,0.000000]}'></div></div>

<div id="pf5" class="pf w0 h0" data-page-no="5"><div class="pc pc5 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62574f3fbd8c6f2306bf6044/bg5.jpg"><div class="t m0 x22 h5 y63 ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 xa h5 y64 ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x22 h5 y65 ff3 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x29 h3 y66 ff1 fs1 fc0 sc1 ls1 ws0">图<span class="_ _7"> </span><span class="ff3 ls2">7 <span class="_"> </span></span>其它互连方式<span class="ff3"> </span></div><div class="t m0 x2a h3 y67 ff1 fs1 fc0 sc0 ls3 ws0">调试工具<span class="ff6 sc1 ls1"> </span></div><div class="t m0 xa h6 y68 ff6 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x2b h3 y69 ff1 fs1 fc0 sc1 ls5 ws0"> 在<span class="_ _6"></span><span class="ff6 ls24">MS-DOS<span class="_"> </span><span class="ff1 ls1">下使用的编程环境是<span class="_ _0"> </span></span><span class="ls25 ws12">TC 2.0</span><span class="ff1 ls1">；<span class="ff6"> </span></span></span></div><div class="t m0 xa h6 y6a ff6 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x12 h3 y6b ff1 fs1 fc0 sc1 ls5 ws0"> 在<span class="_ _6"></span><span class="ff6 ls26 ws13">Windows 2000<span class="_"> </span><span class="ff1 ls1 ws0">下的编程环境是<span class="_ _7"> </span></span><span class="ls14 ws14">VC++ 6.0<span class="ff1 ls1 ws0">；<span class="ff6"> </span></span></span></span></div><div class="t m0 xa h6 y6c ff6 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x2c h3 y6d ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>借助工具：串口调试助手<span class="_ _7"> </span><span class="ff6 ls27">2.1</span>（图<span class="_ _0"> </span><span class="ff6">8</span>）。<span class="ff6"> </span></div><div class="t m0 x2d h6 y6e ff6 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x29 h3 y6f ff1 fs1 fc0 sc1 ls1 ws0">图<span class="_ _7"> </span><span class="ff6">8 <span class="_"> </span></span>串口调试助手<span class="ff6"> </span></div><div class="t m0 x2 h6 y70 ff6 fs1 fc0 sc1 ls1 ws0"> </div><div class="t m0 x2 h3 y71 ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>串口调试助手是由<span class="_ _c"></span>《<span class="ff6 ls28 ws15">Visual C++/Turbo C<span class="_"> </span></span>串口通信编程实践》<span class="_ _c"></span>一书作者龚建伟编写的共享软件，<span class="_ _c"></span>可以方</div><div class="t m0 x2 h3 y72 ff1 fs1 fc0 sc1 ls1 ws0">便地进行串口上的数据收发、<span class="_ _2"></span>显示<span class="_ _2"></span>（<span class="ff6">16<span class="_"> </span></span>进制和<span class="_ _0"> </span><span class="ff6 ls29">ASCI<span class="_ _4"></span>I<span class="_"> </span></span>码方式）<span class="_ _2"></span>和串口参数的设置，<span class="_ _1"></span>在串口调试领域应用广</div><div class="t m0 x2 h3 y73 ff1 fs1 fc0 sc1 ls1 ws0">泛。<span class="ff6"> </span></div><div class="t m0 x2 h3 y74 ff1 fs1 fc0 sc1 ls2a ws0"> <span class="ff6 ls1">"<span class="_ _4"></span></span><span class="ls2b">串口调试助手<span class="ff6 ls1">"<span class="_ _4"></span></span>的开发原<span class="_ _4"></span>理很简单（相信读者<span class="_ _4"></span>看完本文后在相当<span class="_ _4"></span>短的时间之内就<span class="_ _4"></span>能开发出这样的软</span></div><div class="t m0 x2 h3 y75 ff1 fs1 fc0 sc1 ls1 ws0">件），但是作者龚建伟敏<span class="_ _4"></span>锐地抓住了串口<span class="_ _4"></span>调试在业界的需求，<span class="_ _4"></span>使得自身随这一软<span class="_ _4"></span>件而成名。这一<span class="_ _4"></span>事件或多</div><div class="t m0 x2 h3 y76 ff1 fs1 fc0 sc1 ls1 ws0">或少会给程序员们一定的<span class="_ _4"></span>启发。优秀的共<span class="_ _4"></span>享软件不一定要技术<span class="_ _4"></span>含量高，只要有需<span class="_ _4"></span>求，哪怕是开发<span class="_ _4"></span>原理再简</div><div class="t m0 x2 h3 y77 ff1 fs1 fc0 sc1 ls1 ws0">单，都能拥有广泛的使用者。<span class="ff6"> </span></div><div class="t m0 x2 h3 y78 ff1 fs1 fc0 sc1 ls1 ws0"> <span class="_"> </span> <span class="_"> </span>为了在一台<span class="_ _8"> </span><span class="ff6 ls2">PC<span class="_ _a"> </span></span>上同时搭建<span class="_ _8"> </span><span class="ff6 ls7">DOS<span class="_ _a"> </span></span>和<span class="_ _8"> </span><span class="ff6 ls23">Windows<span class="_ _a"> </span></span>平台，我们应该在<span class="_ _8"> </span><span class="ff6 ls23">Windows<span class="_ _a"> </span></span>平台上安装虚拟<span class="_ _8"> </span><span class="ff6 ls1f">PC<span class="_ _8"> </span></span>的软<span class="_ _4"></span>件</div></div><div class="pi" data-data='{"ctm":[1.611639,0.000000,0.000000,1.611639,0.000000,0.000000]}'></div></div>