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<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/62f1c1015425817ffc225dfd/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/62f1c1015425817ffc225dfd/bg1.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x1 h3 y2 ff1 fs0 fc0 sc0 ls0 ws0">LED<span class="_ _0"> </span><span class="ff2">数码有共阳和共阴两种，把这些<span class="_ _1"> </span></span>LED<span class="_ _0"> </span><span class="ff2">发光二极管的正极接到一块（一</span></div><div class="t m0 x2 h3 y3 ff2 fs0 fc0 sc0 ls0 ws0">般是<span class="_ _2"></span>拼成<span class="_ _2"></span>一个<span class="_ _1"> </span><span class="ff1">8<span class="_ _0"> </span></span>字<span class="_ _2"></span>加一<span class="_ _2"></span>个小<span class="_ _2"></span>数点<span class="_ _2"></span>）而<span class="_ _2"></span>作为<span class="_ _2"></span>一个<span class="_ _2"></span>引脚<span class="_ _2"></span>，就<span class="_ _2"></span>叫共<span class="_ _2"></span>阳<span class="_ _2"></span>机<span class="_ _2"></span>极数<span class="_ _2"></span>码管<span class="_ _2"></span>；相</div><div class="t m0 x2 h3 y4 ff2 fs0 fc0 sc0 ls0 ws0">反<span class="_ _3"></span>的<span class="_ _3"></span>，<span class="_ _3"></span>就<span class="_ _3"></span>叫<span class="_ _3"></span>共<span class="_ _4"></span>阴<span class="_ _3"></span>的<span class="_ _5"> </span>（<span class="_ _4"></span>如<span class="_ _3"></span>下<span class="_ _3"></span>图<span class="_ _3"></span>所<span class="_ _3"></span>示<span class="_ _3"></span>）<span class="_ _5"> </span>那<span class="_ _4"></span>么<span class="_ _3"></span>应<span class="_ _3"></span>用<span class="_ _3"></span>时<span class="_ _3"></span>这<span class="_ _4"></span>个<span class="_ _3"></span>脚<span class="_ _3"></span>就<span class="_ _3"></span>分<span class="_ _3"></span>别<span class="_ _3"></span>的<span class="_ _4"></span>接<span class="_ _6"> </span><span class="ff1">VCC<span class="_"> </span></span>和</div><div class="t m0 x2 h3 y5 ff1 fs0 fc0 sc0 ls0 ws0">GND<span class="ff2">。再把多个这样的<span class="_ _0"> </span></span>8<span class="_ _0"> </span><span class="ff2">字装在一起就成了多位的数码管了。</span></div><div class="t m0 x3 h4 y6 ff1 fs0 fc0 sc0 ls0 ws0"> </div><div class="t m0 x1 h3 y7 ff2 fs0 fc0 sc0 ls0 ws0">基于单片机<span class="_ _2"></span>的热水控制器采用<span class="_ _1"> </span><span class="ff1">7<span class="_ _0"> </span></span>段数<span class="_ _0"> </span><span class="ff1">LED<span class="_ _0"> </span></span>码管<span class="_ _2"></span>显示，这里采用<span class="_ _1"> </span><span class="ff1">6<span class="_ _0"> </span></span>个数码管</div><div class="t m0 x2 h3 y8 ff2 fs0 fc0 sc0 ls0 ws0">显示<span class="_ _2"></span>温度<span class="_ _2"></span>，两<span class="_ _2"></span>位显<span class="_ _2"></span>示设<span class="_ _2"></span>定的<span class="_ _2"></span>最高<span class="_ _2"></span>温度<span class="_ _2"></span>、两<span class="_ _2"></span>位显<span class="_ _2"></span>示设<span class="_ _2"></span>定的<span class="_ _2"></span>最低<span class="_ _2"></span>温度<span class="_ _2"></span>、两<span class="_ _2"></span>位显<span class="_ _2"></span>示热</div><div class="t m0 x2 h3 y9 ff2 fs0 fc0 sc0 ls0 ws0">水的当前温度。 </div><div class="t m0 x1 h3 ya ff1 fs0 fc0 sc0 ls0 ws0">6<span class="_ _7"> </span><span class="ff2">位<span class="_ _2"></span>共阳<span class="_ _2"></span>极数<span class="_ _2"></span>码<span class="_ _2"></span>管采<span class="_ _2"></span>用<span class="_ _2"></span>扫描<span class="_ _2"></span>形式<span class="_ _2"></span>工<span class="_ _2"></span>作，<span class="_ _2"></span>其<span class="_"> </span></span>8<span class="_ _0"> </span><span class="ff2">个<span class="_ _2"></span>数据<span class="_ _2"></span>为接<span class="_ _2"></span>在<span class="_ _2"></span>单片<span class="_ _2"></span>机<span class="_ _2"></span>灌电<span class="_ _2"></span>流驱</span></div><div class="t m0 x2 h3 yb ff2 fs0 fc0 sc0 ls0 ws0">动<span class="_ _2"></span>能力<span class="_ _2"></span>最大<span class="_ _2"></span>的<span class="_ _1"> </span><span class="ff1">PO<span class="_ _7"> </span></span>口<span class="_ _2"></span>，<span class="ff1">A<span class="_ _8"></span>T89C51<span class="_ _0"> </span><span class="ff2">单<span class="_ _2"></span>片<span class="_ _2"></span>机的<span class="_ _1"> </span></span>P0<span class="_ _0"> </span><span class="ff2">口<span class="_ _2"></span>的<span class="_ _2"></span>每一<span class="_ _2"></span>个<span class="_ _7"> </span></span>I<span class="_ _2"></span>/O<span class="_ _0"> </span><span class="ff2">都<span class="_ _2"></span>能能<span class="_ _2"></span>吸<span class="_ _2"></span>收<span class="_ _7"> </span></span>8<span class="_ _7"> </span><span class="ff2">个</span></span></div><div class="t m0 x2 h3 yc ff1 fs0 fc0 sc0 ls0 ws0">TTL<span class="_ _0"> </span><span class="ff2">逻辑器<span class="_ _2"></span>件的<span class="_ _2"></span>输入漏<span class="_ _2"></span>电流，<span class="_ _2"></span>算下<span class="_ _2"></span>来能驱<span class="_ _2"></span>动约<span class="_"> </span></span>10mA<span class="ff2">。能<span class="_ _2"></span>驱动<span class="_ _2"></span>数码管<span class="_ _2"></span>的<span class="_ _7"> </span></span>8<span class="_ _7"> </span><span class="ff2">个数</span></div><div class="t m0 x2 h3 yd ff2 fs0 fc0 sc0 ls0 ws0">据阴极。</div><div class="t m0 x1 h3 ye ff1 fs0 fc0 sc0 ls0 ws0">6<span class="_ _1"> </span><span class="ff2">位<span class="_ _9"></span>共<span class="_ _2"></span>阳<span class="_ _9"></span>极<span class="_ _9"></span>数<span class="_ _9"></span>码<span class="_ _2"></span>的<span class="_"> </span></span>6<span class="_ _7"> </span><span class="ff2">个<span class="_ _9"></span>阳<span class="_ _9"></span>极<span class="_ _9"></span>采<span class="_ _2"></span>用<span class="_ _a"> </span></span>6<span class="_ _1"> </span><span class="ff2">个<span class="_ _1"> </span></span>PNP<span class="_ _1"> </span><span class="ff2">三<span class="_ _2"></span>极<span class="_ _9"></span>管<span class="_ _1"> </span></span>9012<span class="_ _a"> </span><span class="ff2">驱<span class="_ _2"></span>动<span class="_ _9"></span>。<span class="_ _9"></span>用<span class="_ _2"></span>单<span class="_ _9"></span>片<span class="_ _9"></span>机</span></div><div class="t m0 x2 h3 yf ff1 fs0 fc0 sc0 ls0 ws0">P2.0-P2.5 6<span class="_ _0"> </span><span class="ff2">个<span class="_ _0"> </span></span>I/O<span class="_ _0"> </span><span class="ff2">口控制。</span></div><div class="t m0 x4 h3 y10 ff1 fs0 fc0 sc0 ls0 ws0">LED<span class="_ _0"> </span><span class="ff2">数码管显示电路如图<span class="_ _0"> </span></span>4.4<span class="_ _0"> </span><span class="ff2">所示。</span></div><div class="t m0 x5 h5 y11 ff2 fs1 fc0 sc0 ls0 ws0">图<span class="_ _b"> </span><span class="ff1">4.4 </span>数码管显示电路</div></div><div class="t m0 x6 h3 y12 ff2 fs0 fc0 sc0 ls0 ws0">图<span class="_ _0"> </span><span class="ff3">4.3 <span class="fs1"> </span></span>共阴极和共阳极数码管内部电路</div><div class="c x7 y13 w3 h6"><div class="t m1 x8 h7 y14 ff3 fs2 fc1 sc0 ls0 ws0">R3</div><div class="t m1 x8 h7 y15 ff3 fs2 fc1 sc0 ls0 ws0">R4</div><div class="t m1 x8 h7 y16 ff3 fs2 fc1 sc0 ls0 ws0">R5</div><div class="t m1 x8 h7 y17 ff3 fs2 fc1 sc0 ls0 ws0">R6</div><div class="t m1 x9 h7 y18 ff3 fs2 fc1 sc0 ls0 ws0">R10</div><div class="t m1 x9 h7 y19 ff3 fs2 fc1 sc0 ls0 ws0">R11</div><div class="t m1 x9 h7 y1a ff3 fs2 fc1 sc0 ls0 ws0">R12</div><div class="t m1 xa h7 y14 ff3 fs2 fc2 sc0 ls0 ws0">L1</div><div class="t m1 xa h7 y15 ff3 fs2 fc2 sc0 ls0 ws0">L2</div><div class="t m1 xa h7 y16 ff3 fs2 fc2 sc0 ls0 ws0">L3</div><div class="t m1 xa h7 y17 ff3 fs2 fc2 sc0 ls0 ws0">L4</div><div class="t m1 xa h7 y18 ff3 fs2 fc2 sc0 ls0 ws0">L5</div><div class="t m1 xa h7 y19 ff3 fs2 fc2 sc0 ls0 ws0">L6</div><div class="t m1 xa h7 y1a ff3 fs2 fc2 sc0 ls0 ws0">L7</div><div class="t m1 xa h7 y1b ff3 fs2 fc2 sc0 ls0 ws0">L8</div><div class="t m1 xb h7 y14 ff3 fs2 fc2 sc0 ls0 ws0">L1</div><div class="t m1 xb h7 y15 ff3 fs2 fc2 sc0 ls0 ws0">L2</div><div class="t m1 xb h7 y16 ff3 fs2 fc2 sc0 ls0 ws0">L3</div><div class="t m1 xb h7 y17 ff3 fs2 fc2 sc0 ls0 ws0">L4</div><div class="t m1 xb h7 y18 ff3 fs2 fc2 sc0 ls0 ws0">L5</div><div class="t m1 xb h7 y19 ff3 fs2 fc2 sc0 ls0 ws0">L6</div><div class="t m1 xb h7 y1a ff3 fs2 fc2 sc0 ls0 ws0">L7</div><div class="t m1 xc h7 y1c ff3 fs2 fc1 sc0 ls0 ws0">1k</div><div class="t m1 xc h7 y1d ff3 fs2 fc1 sc0 ls0 ws0">R13</div><div class="t m1 xd h7 y1c ff3 fs2 fc1 sc0 ls0 ws0">1k</div><div class="t m1 xd h7 y1d ff3 fs2 fc1 sc0 ls0 ws0">R15</div><div class="t m1 xe h7 y1c ff3 fs2 fc1 sc0 ls0 ws0">1k</div><div class="t m1 xe h7 y1d ff3 fs2 fc1 sc0 ls0 ws0">R16</div><div class="t m1 xf h7 y1e ff3 fs2 fc1 sc0 ls0 ws0">Q5</div><div class="t m1 xf h7 y1f ff3 fs2 fc1 sc0 ls0 ws0">9012</div><div class="t m1 x10 h7 y1e ff3 fs2 fc1 sc0 ls0 ws0">Q6</div><div class="t m1 x10 h7 y1f ff3 fs2 fc1 sc0 ls0 ws0">9012</div><div class="t m1 x11 h7 y1e ff3 fs2 fc1 sc0 ls0 ws0">Q7</div><div class="t m1 x11 h7 y1f ff3 fs2 fc1 sc0 ls0 ws0">9012</div><div class="t m1 x12 h7 y20 ff3 fs2 fc0 sc0 ls0 ws0">f</div><div class="t m1 x13 h7 y19 ff3 fs2 fc0 sc0 ls0 ws0">9</div><div class="t m1 x12 h7 y21 ff3 fs2 fc0 sc0 ls0 ws0">g</div><div class="t m1 x14 h7 y1a ff3 fs2 fc0 sc0 ls0 ws0">10</div><div class="t m1 x12 h7 y22 ff3 fs2 fc0 sc0 ls0 ws0">e</div><div class="t m1 x13 h7 y18 ff3 fs2 fc0 sc0 ls0 ws0">1</div><div class="t m1 x12 h7 y23 ff3 fs2 fc0 sc0 ls0 ws0">d</div><div class="t m1 x13 h7 y17 ff3 fs2 fc0 sc0 ls0 ws0">2</div><div class="t m1 x15 h7 y24 ff3 fs2 fc0 sc0 ls0 ws0">+</div><div class="t m1 x16 h7 y14 ff3 fs2 fc0 sc0 ls0 ws0">3</div><div class="t m1 x12 h7 y25 ff3 fs2 fc0 sc0 ls0 ws0">c</div><div class="t m1 x13 h7 y16 ff3 fs2 fc0 sc0 ls0 ws0">4</div><div class="t m1 x12 h7 y26 ff3 fs2 fc0 sc0 ls0 ws0">DP</div><div class="t m1 x13 h7 y1b ff3 fs2 fc0 sc0 ls0 ws0">5</div><div class="t m1 x12 h7 y27 ff3 fs2 fc0 sc0 ls0 ws0">b</div><div class="t m1 x13 h7 y15 ff3 fs2 fc0 sc0 ls0 ws0">6</div><div class="t m1 x12 h7 y24 ff3 fs2 fc0 sc0 ls0 ws0">a</div><div class="t m1 x13 h7 y14 ff3 fs2 fc0 sc0 ls0 ws0">7</div><div class="t m1 x15 h7 y27 ff3 fs2 fc0 sc0 ls0 ws0">+</div><div class="t m1 x16 h7 y15 ff3 fs2 fc0 sc0 ls0 ws0">8</div><div class="t m1 x17 h7 y28 ff3 fs2 fc1 sc0 ls0 ws0">DS1</div><div class="t m1 x18 h7 y20 ff3 fs2 fc0 sc0 ls0 ws0">f</div><div class="t m1 x19 h7 y19 ff3 fs2 fc0 sc0 ls0 ws0">9</div><div class="t m1 x18 h7 y21 ff3 fs2 fc0 sc0 ls0 ws0">g</div><div class="t m1 x1a h7 y1a ff3 fs2 fc0 sc0 ls0 ws0">10</div><div class="t m1 x18 h7 y22 ff3 fs2 fc0 sc0 ls0 ws0">e</div><div class="t m1 x19 h7 y18 ff3 fs2 fc0 sc0 ls0 ws0">1</div><div class="t m1 x18 h7 y23 ff3 fs2 fc0 sc0 ls0 ws0">d</div><div class="t m1 x19 h7 y17 ff3 fs2 fc0 sc0 ls0 ws0">2</div><div class="t m1 x1b h7 y24 ff3 fs2 fc0 sc0 ls0 ws0">+</div><div class="t m1 x1c h7 y14 ff3 fs2 fc0 sc0 ls0 ws0">3</div><div class="t m1 x18 h7 y25 ff3 fs2 fc0 sc0 ls0 ws0">c</div><div class="t m1 x19 h7 y16 ff3 fs2 fc0 sc0 ls0 ws0">4</div><div class="t m1 x18 h7 y26 ff3 fs2 fc0 sc0 ls0 ws0">DP</div><div class="t m1 x19 h7 y1b ff3 fs2 fc0 sc0 ls0 ws0">5</div><div class="t m1 x18 h7 y27 ff3 fs2 fc0 sc0 ls0 ws0">b</div><div class="t m1 x19 h7 y15 ff3 fs2 fc0 sc0 ls0 ws0">6</div><div class="t m1 x18 h7 y24 ff3 fs2 fc0 sc0 ls0 ws0">a</div><div class="t m1 x19 h7 y14 ff3 fs2 fc0 sc0 ls0 ws0">7</div><div class="t m1 x1b h7 y27 ff3 fs2 fc0 sc0 ls0 ws0">+</div><div class="t m1 x1c h7 y15 ff3 fs2 fc0 sc0 ls0 ws0">8</div><div class="t m1 x1d h7 y28 ff3 fs2 fc1 sc0 ls0 ws0">DS2</div><div class="t m1 x1e h7 y20 ff3 fs2 fc0 sc0 ls0 ws0">f</div><div class="t m1 x1f h7 y19 ff3 fs2 fc0 sc0 ls0 ws0">9</div><div class="t m1 x1e h7 y21 ff3 fs2 fc0 sc0 ls0 ws0">g</div><div class="t m1 x20 h7 y1a ff3 fs2 fc0 sc0 ls0 ws0">10</div><div class="t m1 x1e h7 y22 ff3 fs2 fc0 sc0 ls0 ws0">e</div><div class="t m1 x1f h7 y18 ff3 fs2 fc0 sc0 ls0 ws0">1</div><div class="t m1 x1e h7 y23 ff3 fs2 fc0 sc0 ls0 ws0">d</div><div class="t m1 x1f h7 y17 ff3 fs2 fc0 sc0 ls0 ws0">2</div><div class="t m1 x21 h7 y24 ff3 fs2 fc0 sc0 ls0 ws0">+</div><div class="t m1 x22 h7 y14 ff3 fs2 fc0 sc0 ls0 ws0">3</div><div class="t m1 x1e h7 y25 ff3 fs2 fc0 sc0 ls0 ws0">c</div><div class="t m1 x1f h7 y16 ff3 fs2 fc0 sc0 ls0 ws0">4</div><div class="t m1 x1e h7 y26 ff3 fs2 fc0 sc0 ls0 ws0">DP</div><div class="t m1 x1f h7 y1b ff3 fs2 fc0 sc0 ls0 ws0">5</div><div class="t m1 x1e h7 y27 ff3 fs2 fc0 sc0 ls0 ws0">b</div><div class="t m1 x1f h7 y15 ff3 fs2 fc0 sc0 ls0 ws0">6</div><div class="t m1 x1e h7 y24 ff3 fs2 fc0 sc0 ls0 ws0">a</div><div class="t m1 x1f h7 y14 ff3 fs2 fc0 sc0 ls0 ws0">7</div><div class="t m1 x21 h7 y27 ff3 fs2 fc0 sc0 ls0 ws0">+</div><div class="t m1 x22 h7 y15 ff3 fs2 fc0 sc0 ls0 ws0">8</div><div class="t m1 x23 h7 y28 ff3 fs2 fc1 sc0 ls0 ws0">DS3</div><div class="t m1 x9 h7 y1b ff3 fs2 fc1 sc0 ls0 ws0">R32</div><div class="t m1 x24 h7 y29 ff3 fs2 fc1 sc0 ls0 ws0">300X8</div><div class="t m1 x25 h7 y14 ff3 fs2 fc2 sc0 ls0 ws0">L1</div><div class="t m1 x25 h7 y15 ff3 fs2 fc2 sc0 ls0 ws0">L2</div><div class="t m1 x25 h7 y16 ff3 fs2 fc2 sc0 ls0 ws0">L3</div><div class="t m1 x25 h7 y17 ff3 fs2 fc2 sc0 ls0 ws0">L4</div><div class="t m1 x25 h7 y18 ff3 fs2 fc2 sc0 ls0 ws0">L5</div><div class="t m1 x25 h7 y19 ff3 fs2 fc2 sc0 ls0 ws0">L6</div><div class="t m1 x25 h7 y1a ff3 fs2 fc2 sc0 ls0 ws0">L7</div><div class="t m1 x25 h7 y1b ff3 fs2 fc2 sc0 ls0 ws0">L8</div><div class="t m1 x26 h7 y2a ff3 fs2 fc2 sc0 ls0 ws0">VCC</div><div class="t m1 xb h7 y1b ff3 fs2 fc2 sc0 ls0 ws0">L8</div><div class="t m1 x27 h7 y14 ff3 fs2 fc2 sc0 ls0 ws0">D0</div><div class="t m1 x27 h7 y15 ff3 fs2 fc2 sc0 ls0 ws0">D1</div><div class="t m1 x27 h7 y16 ff3 fs2 fc2 sc0 ls0 ws0">D2</div><div class="t m1 x27 h7 y17 ff3 fs2 fc2 sc0 ls0 ws0">D3</div><div class="t m1 x27 h7 y18 ff3 fs2 fc2 sc0 ls0 ws0">D4</div><div class="t m1 x27 h7 y19 ff3 fs2 fc2 sc0 ls0 ws0">D5</div><div class="t m1 x27 h7 y1a ff3 fs2 fc2 sc0 ls0 ws0">D6</div><div class="t m1 x27 h7 y1b ff3 fs2 fc2 sc0 ls0 ws0">D7</div><div class="t m1 x28 h8 y29 ff2 fs2 fc1 sc0 ls0 ws0">至单片<span class="_ _c"></span>机数据<span class="_ _c"></span>总线</div><div class="t m1 x29 h8 y2b ff3 fs2 fc1 sc0 ls0 ws0">I/0<span class="_ _d"></span><span class="ff2">至单<span class="_ _c"></span>片机<span class="_ _6"> </span>口</span></div><div class="t m1 x2a h7 y14 ff3 fs2 fc2 sc0 ls0 ws0">L1</div><div class="t m1 x2a h7 y15 ff3 fs2 fc2 sc0 ls0 ws0">L2</div><div class="t m1 x2a h7 y16 ff3 fs2 fc2 sc0 ls0 ws0">L3</div><div class="t m1 x2a h7 y17 ff3 fs2 fc2 sc0 ls0 ws0">L4</div><div class="t m1 x2a h7 y18 ff3 fs2 fc2 sc0 ls0 ws0">L5</div><div class="t m1 x2a h7 y19 ff3 fs2 fc2 sc0 ls0 ws0">L6</div><div class="t m1 x2a h7 y1a ff3 fs2 fc2 sc0 ls0 ws0">L7</div><div class="t m1 x2a h7 y1b ff3 fs2 fc2 sc0 ls0 ws0">L8</div><div class="t m1 x2b h7 y14 ff3 fs2 fc2 sc0 ls0 ws0">L1</div><div class="t m1 x2b h7 y15 ff3 fs2 fc2 sc0 ls0 ws0">L2</div><div class="t m1 x2b h7 y16 ff3 fs2 fc2 sc0 ls0 ws0">L3</div><div class="t m1 x2b h7 y17 ff3 fs2 fc2 sc0 ls0 ws0">L4</div><div class="t m1 x2b h7 y18 ff3 fs2 fc2 sc0 ls0 ws0">L5</div><div class="t m1 x2b h7 y19 ff3 fs2 fc2 sc0 ls0 ws0">L6</div><div class="t m1 x2b h7 y1a ff3 fs2 fc2 sc0 ls0 ws0">L7</div><div class="t m1 x2c h7 y1c ff3 fs2 fc1 sc0 ls0 ws0">1k</div><div class="t m1 x2c h7 y1d ff3 fs2 fc1 sc0 ls0 ws0">R17</div><div class="t m1 x2d h7 y1c ff3 fs2 fc1 sc0 ls0 ws0">1k</div><div class="t m1 x2d h7 y1d ff3 fs2 fc1 sc0 ls0 ws0">R18</div><div class="t m1 x2e h7 y1c ff3 fs2 fc1 sc0 ls0 ws0">1k</div><div class="t m1 x2e h7 y1d ff3 fs2 fc1 sc0 ls0 ws0">R19</div><div class="t m1 x2f h7 y2c ff3 fs2 fc1 sc0 ls0 ws0">Q8</div><div class="t m1 x30 h7 y1f ff3 fs2 fc1 sc0 ls0 ws0">9012</div><div class="t m1 x31 h7 y1e ff3 fs2 fc1 sc0 ls0 ws0">Q9</div><div class="t m1 x31 h7 y1f ff3 fs2 fc1 sc0 ls0 ws0">9012</div><div class="t m1 x32 h7 y1e ff3 fs2 fc1 sc0 ls0 ws0">Q10</div><div class="t m1 x32 h7 y1f ff3 fs2 fc1 sc0 ls0 ws0">9012</div><div class="t m1 x33 h7 y20 ff3 fs2 fc0 sc0 ls0 ws0">f</div><div class="t m1 x34 h7 y19 ff3 fs2 fc0 sc0 ls0 ws0">9</div><div class="t m1 x33 h7 y21 ff3 fs2 fc0 sc0 ls0 ws0">g</div><div class="t m1 x35 h7 y1a ff3 fs2 fc0 sc0 ls0 ws0">10</div><div class="t m1 x33 h7 y22 ff3 fs2 fc0 sc0 ls0 ws0">e</div><div class="t m1 x34 h7 y18 ff3 fs2 fc0 sc0 ls0 ws0">1</div><div class="t m1 x33 h7 y23 ff3 fs2 fc0 sc0 ls0 ws0">d</div><div class="t m1 x34 h7 y17 ff3 fs2 fc0 sc0 ls0 ws0">2</div><div class="t m1 x36 h7 y24 ff3 fs2 fc0 sc0 ls0 ws0">+</div><div class="t m1 x37 h7 y14 ff3 fs2 fc0 sc0 ls0 ws0">3</div><div class="t m1 x33 h7 y25 ff3 fs2 fc0 sc0 ls0 ws0">c</div><div class="t m1 x34 h7 y16 ff3 fs2 fc0 sc0 ls0 ws0">4</div><div class="t m1 x33 h7 y26 ff3 fs2 fc0 sc0 ls0 ws0">DP</div><div class="t m1 x34 h7 y1b ff3 fs2 fc0 sc0 ls0 ws0">5</div><div class="t m1 x33 h7 y27 ff3 fs2 fc0 sc0 ls0 ws0">b</div><div class="t m1 x34 h7 y15 ff3 fs2 fc0 sc0 ls0 ws0">6</div><div class="t m1 x33 h7 y24 ff3 fs2 fc0 sc0 ls0 ws0">a</div><div class="t m1 x34 h7 y14 ff3 fs2 fc0 sc0 ls0 ws0">7</div><div class="t m1 x36 h7 y27 ff3 fs2 fc0 sc0 ls0 ws0">+</div><div class="t m1 x37 h7 y15 ff3 fs2 fc0 sc0 ls0 ws0">8</div><div class="t m1 x38 h7 y28 ff3 fs2 fc1 sc0 ls0 ws0">DS4</div><div class="t m1 x39 h7 y20 ff3 fs2 fc0 sc0 ls0 ws0">f</div><div class="t m1 x3a h7 y19 ff3 fs2 fc0 sc0 ls0 ws0">9</div><div class="t m1 x39 h7 y21 ff3 fs2 fc0 sc0 ls0 ws0">g</div><div class="t m1 x3b h7 y1a ff3 fs2 fc0 sc0 ls0 ws0">10</div><div class="t m1 x39 h7 y22 ff3 fs2 fc0 sc0 ls0 ws0">e</div><div class="t m1 x3a h7 y18 ff3 fs2 fc0 sc0 ls0 ws0">1</div><div class="t m1 x39 h7 y23 ff3 fs2 fc0 sc0 ls0 ws0">d</div><div class="t m1 x3a h7 y17 ff3 fs2 fc0 sc0 ls0 ws0">2</div><div class="t m1 x3c h7 y24 ff3 fs2 fc0 sc0 ls0 ws0">+</div><div class="t m1 x3d h7 y14 ff3 fs2 fc0 sc0 ls0 ws0">3</div><div class="t m1 x39 h7 y25 ff3 fs2 fc0 sc0 ls0 ws0">c</div><div class="t m1 x3a h7 y16 ff3 fs2 fc0 sc0 ls0 ws0">4</div><div class="t m1 x39 h7 y26 ff3 fs2 fc0 sc0 ls0 ws0">DP</div><div class="t m1 x3a h7 y1b ff3 fs2 fc0 sc0 ls0 ws0">5</div><div class="t m1 x39 h7 y27 ff3 fs2 fc0 sc0 ls0 ws0">b</div><div class="t m1 x3a h7 y15 ff3 fs2 fc0 sc0 ls0 ws0">6</div><div class="t m1 x39 h7 y24 ff3 fs2 fc0 sc0 ls0 ws0">a</div><div class="t m1 x3a h7 y14 ff3 fs2 fc0 sc0 ls0 ws0">7</div><div class="t m1 x3c h7 y27 ff3 fs2 fc0 sc0 ls0 ws0">+</div><div class="t m1 x3d h7 y15 ff3 fs2 fc0 sc0 ls0 ws0">8</div><div class="t m1 x3e h7 y28 ff3 fs2 fc1 sc0 ls0 ws0">DS5</div><div class="t m1 x3f h7 y20 ff3 fs2 fc0 sc0 ls0 ws0">f</div><div class="t m1 x40 h7 y19 ff3 fs2 fc0 sc0 ls0 ws0">9</div><div class="t m1 x3f h7 y21 ff3 fs2 fc0 sc0 ls0 ws0">g</div><div class="t m1 x41 h7 y1a ff3 fs2 fc0 sc0 ls0 ws0">10</div><div class="t m1 x3f h7 y22 ff3 fs2 fc0 sc0 ls0 ws0">e</div><div class="t m1 x40 h7 y18 ff3 fs2 fc0 sc0 ls0 ws0">1</div><div class="t m1 x3f h7 y23 ff3 fs2 fc0 sc0 ls0 ws0">d</div><div class="t m1 x40 h7 y17 ff3 fs2 fc0 sc0 ls0 ws0">2</div><div class="t m1 x42 h7 y24 ff3 fs2 fc0 sc0 ls0 ws0">+</div><div class="t m1 x43 h7 y14 ff3 fs2 fc0 sc0 ls0 ws0">3</div><div class="t m1 x3f h7 y25 ff3 fs2 fc0 sc0 ls0 ws0">c</div><div class="t m1 x40 h7 y16 ff3 fs2 fc0 sc0 ls0 ws0">4</div><div class="t m1 x3f h7 y26 ff3 fs2 fc0 sc0 ls0 ws0">DP</div><div class="t m1 x40 h7 y1b ff3 fs2 fc0 sc0 ls0 ws0">5</div><div class="t m1 x3f h7 y27 ff3 fs2 fc0 sc0 ls0 ws0">b</div><div class="t m1 x40 h7 y15 ff3 fs2 fc0 sc0 ls0 ws0">6</div><div class="t m1 x3f h7 y24 ff3 fs2 fc0 sc0 ls0 ws0">a</div><div class="t m1 x40 h7 y14 ff3 fs2 fc0 sc0 ls0 ws0">7</div><div class="t m1 x42 h7 y27 ff3 fs2 fc0 sc0 ls0 ws0">+</div><div class="t m1 x43 h7 y15 ff3 fs2 fc0 sc0 ls0 ws0">8</div><div class="t m1 x44 h7 y28 ff3 fs2 fc1 sc0 ls0 ws0">DS6</div><div class="t m1 x45 h7 y14 ff3 fs2 fc2 sc0 ls0 ws0">L1</div><div class="t m1 x45 h7 y15 ff3 fs2 fc2 sc0 ls0 ws0">L2</div><div class="t m1 x45 h7 y16 ff3 fs2 fc2 sc0 ls0 ws0">L3</div><div class="t m1 x45 h7 y17 ff3 fs2 fc2 sc0 ls0 ws0">L4</div><div class="t m1 x45 h7 y18 ff3 fs2 fc2 sc0 ls0 ws0">L5</div><div class="t m1 x45 h7 y19 ff3 fs2 fc2 sc0 ls0 ws0">L6</div><div class="t m1 x45 h7 y1a ff3 fs2 fc2 sc0 ls0 ws0">L7</div><div class="t m1 x45 h7 y1b ff3 fs2 fc2 sc0 ls0 ws0">L8<span class="_ _e"></span>L8</div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></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/62f1c1015425817ffc225dfd/bg2.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x2 h3 y2d ff4 fs0 fc0 sc0 ls0 ws0">4.1.3 <span class="ff2 sc1">报警及控制输出部分</span></div><div class="t m0 x1 h3 y2e ff2 fs0 fc0 sc0 ls0 ws0">当<span class="_ _2"></span>水<span class="_ _2"></span>温<span class="_ _2"></span>超过<span class="_ _2"></span>最<span class="_ _2"></span>高<span class="_ _2"></span>温<span class="_ _2"></span>度<span class="_ _9"></span><span class="ff1">+3<span class="_ _7"> </span></span>度<span class="_ _2"></span>时<span class="_ _2"></span>，<span class="_ _2"></span>热<span class="_ _2"></span>水<span class="_ _2"></span>控制<span class="_ _2"></span>器<span class="_ _2"></span>需<span class="_ _2"></span>停<span class="_ _2"></span>止<span class="_ _2"></span>加<span class="_ _2"></span>热<span class="_ _2"></span>并报<span class="_ _2"></span>警<span class="_ _2"></span>；<span class="_ _2"></span>当<span class="_ _2"></span>水<span class="_ _2"></span>位<span class="_ _2"></span>低</div><div class="t m0 x2 h3 y2f ff2 fs0 fc0 sc0 ls0 ws0">于最低温度<span class="ff1">-3<span class="_ _0"> </span></span>度时，需开始加热，这就需要报警电路及输出模块。</div><div class="t m0 x1 h3 y30 ff2 fs0 fc0 sc0 ls0 ws0">声<span class="_ _2"></span>音<span class="_ _2"></span>报<span class="_ _2"></span>警电<span class="_ _2"></span>路<span class="_ _2"></span>通<span class="_ _2"></span>过<span class="_ _2"></span>驱<span class="_ _2"></span>动<span class="_ _2"></span>蜂<span class="_ _2"></span>鸣器<span class="_ _2"></span>发<span class="_ _2"></span>声<span class="_ _2"></span>实<span class="_ _2"></span>现<span class="_ _2"></span>，<span class="_ _2"></span>当<span class="_ _2"></span>其接<span class="_ _2"></span>通<span class="_ _a"> </span><span class="ff1">5V<span class="_ _7"> </span></span>的<span class="_ _2"></span>电<span class="_ _2"></span>压<span class="_ _2"></span>会发<span class="_ _2"></span>出<span class="_ _2"></span>蜂<span class="_ _2"></span>鸣</div><div class="t m0 x2 h3 y31 ff2 fs0 fc0 sc0 ls0 ws0">叫<span class="_ _2"></span>声。<span class="_ _2"></span>原<span class="_ _2"></span>理<span class="_ _2"></span>图如<span class="_ _2"></span>图<span class="_ _1"> </span><span class="ff1">4.5<span class="_ _2"></span></span>，<span class="_ _2"></span><span class="ff1">NPN<span class="_ _7"> </span></span>型<span class="_ _2"></span>三极<span class="_ _2"></span>管<span class="_ _7"> </span><span class="ff1">8050<span class="_ _1"> </span></span>驱动<span class="_ _2"></span>蜂<span class="_ _2"></span>鸣<span class="_ _2"></span>器，<span class="_ _2"></span>当<span class="_ _2"></span>单<span class="_ _2"></span>片机<span class="_ _1"> </span><span class="ff1">I/<span class="_ _2"></span>O<span class="_ _0"> </span></span>口<span class="_ _2"></span>输</div><div class="t m0 x2 h3 y32 ff2 fs0 fc0 sc0 ls0 ws0">出高电平时蜂鸣器发声</div><div class="t m0 x1 h3 y33 ff2 fs0 fc0 sc0 ls0 ws0">此<span class="_ _2"></span>外，<span class="_ _2"></span>控<span class="_ _2"></span>制<span class="_ _2"></span>加热<span class="_ _2"></span>棒<span class="_ _2"></span>的<span class="_ _2"></span>控制<span class="_ _2"></span>信<span class="_ _2"></span>号<span class="_ _2"></span>同样<span class="_ _2"></span>由<span class="_ _2"></span>单<span class="_ _2"></span>片机<span class="_ _2"></span>输<span class="_ _2"></span>出<span class="_ _2"></span>，经<span class="_ _2"></span>过<span class="_ _2"></span>三<span class="_ _2"></span>极管<span class="_"> </span><span class="ff1">Q3<span class="_ _7"> </span></span>驱<span class="_ _2"></span>动<span class="_ _2"></span>继</div><div class="t m0 x2 h3 y34 ff2 fs0 fc0 sc0 ls0 ws0">电<span class="_ _2"></span>器<span class="_ _7"> </span><span class="ff1">J1<span class="_ _2"></span></span>，<span class="_ _2"></span> <span class="ff1">J<span class="_ _2"></span>1 <span class="_ _2"></span></span>具<span class="_ _2"></span>有<span class="_ _2"></span>两<span class="_ _2"></span>对常<span class="_ _2"></span>开<span class="_ _2"></span>和<span class="_ _2"></span>常闭<span class="_ _2"></span>接<span class="_ _2"></span>点<span class="_ _2"></span>，利<span class="_ _2"></span>用<span class="_ _2"></span>其<span class="_ _2"></span>常开<span class="_ _2"></span>接<span class="_ _2"></span>点<span class="_ _2"></span>串到<span class="_ _2"></span>加<span class="_ _2"></span>热<span class="_ _2"></span>棒的<span class="_ _2"></span>控<span class="_ _2"></span>制<span class="_ _2"></span>回</div><div class="t m0 x2 h3 y35 ff2 fs0 fc0 sc0 ls0 ws0">路中<span class="_ _2"></span>，可以<span class="_ _2"></span>实现<span class="_ _2"></span>加热棒的<span class="_ _2"></span>控制<span class="_ _2"></span>。电路<span class="_ _2"></span>中二极<span class="_ _2"></span>管<span class="_"> </span><span class="ff1">D1<span class="_ _0"> </span></span>为续流<span class="_ _2"></span>二极<span class="_ _2"></span>管， <span class="_ _2"></span>继电器<span class="_ _9"></span>线<span class="_ _2"></span>圈</div><div class="t m0 x2 h3 y36 ff2 fs0 fc0 sc0 ls0 ws0">在通<span class="_ _2"></span>过电<span class="_ _2"></span>流时<span class="_ _2"></span>，会<span class="_ _2"></span>在其<span class="_ _2"></span>两端<span class="_ _2"></span>产生<span class="_ _2"></span>感应<span class="_ _2"></span>电动<span class="_ _2"></span>势。<span class="_ _2"></span>当电<span class="_ _2"></span>流消<span class="_ _2"></span>失时<span class="_ _2"></span>，其<span class="_ _2"></span>感应<span class="_ _2"></span>电动<span class="_ _2"></span>势会</div><div class="t m0 x2 h3 y37 ff2 fs0 fc0 sc0 ls0 ws0">对<span class="_ _2"></span>电路<span class="_ _2"></span>中<span class="_ _2"></span>的<span class="_ _2"></span>三<span class="_ _2"></span>极管<span class="_ _7"> </span><span class="ff1">Q<span class="_ _2"></span>3<span class="_ _0"> </span></span>产<span class="_ _2"></span>生<span class="_ _2"></span>反向<span class="_ _2"></span>电<span class="_ _2"></span>压<span class="_ _2"></span>。当<span class="_ _2"></span>反<span class="_ _2"></span>向<span class="_ _2"></span>电压<span class="_ _2"></span>高<span class="_ _2"></span>于<span class="_ _1"> </span><span class="ff1">Q3<span class="_ _2"></span> </span>的<span class="_ _2"></span>反<span class="_ _2"></span>向<span class="_ _2"></span>击穿<span class="_ _2"></span>电<span class="_ _2"></span>压<span class="_ _2"></span>时<span class="_ _2"></span>，</div><div class="t m0 x2 h3 y38 ff2 fs0 fc0 sc0 ls0 ws0">会把<span class="_ _2"></span>三极<span class="_ _2"></span>管成<span class="_ _2"></span>损坏<span class="_ _2"></span>。续<span class="_ _2"></span>流二<span class="_ _2"></span>极管<span class="_ _2"></span>并联<span class="_ _2"></span>在线<span class="_ _9"></span>圈<span class="_ _2"></span>两端<span class="_ _2"></span>，当<span class="_ _2"></span>流过<span class="_ _2"></span>线圈<span class="_ _2"></span>中的<span class="_ _2"></span>电流<span class="_ _2"></span>消失<span class="_ _2"></span>时<span class="_ _2"></span>，</div><div class="t m0 x2 h3 y39 ff2 fs0 fc0 sc0 ls0 ws0">线圈<span class="_ _2"></span>产生<span class="_ _2"></span>的感<span class="_ _2"></span>应电<span class="_ _2"></span>动势<span class="_ _2"></span>通过<span class="_ _2"></span>二极<span class="_ _2"></span>管和<span class="_ _2"></span>线圈<span class="_ _2"></span>构成<span class="_ _2"></span>的回<span class="_ _2"></span>路做<span class="_ _2"></span>功而<span class="_ _2"></span>消耗<span class="_ _2"></span>掉。<span class="_ _3"></span>从而<span class="_ _2"></span>保护</div><div class="t m0 x2 h3 y3a ff2 fs0 fc0 sc0 ls0 ws0">了电路中的三极管的安全。</div></div><div class="c x16 y3b w4 h9"><div class="t m0 x46 ha y3c ff2 fs3 fc1 sc0 ls0 ws0">蜂鸣<span class="_ _c"></span>器</div><div class="t m0 x47 hb y3d ff3 fs3 fc1 sc0 ls0 ws0">Q4</div><div class="t m0 x47 hb y3e ff3 fs3 fc1 sc0 ls0 ws0">8050</div><div class="t m0 x48 hb y3f ff3 fs3 fc1 sc0 ls0 ws0">1k</div><div class="t m0 x48 hb y40 ff3 fs3 fc1 sc0 ls0 ws0">R27</div><div class="t m0 x49 hb y41 ff3 fs3 fc2 sc0 ls0 ws0">VCC</div><div class="t m0 x4a hb y42 ff3 fs3 fc1 sc0 ls0 ws0">J1</div><div class="t m0 x6 hb y43 ff3 fs3 fc1 sc0 ls0 ws0">DC 5<span class="_ _c"></span>V</div><div class="t m0 x4b hb y3d ff3 fs3 fc1 sc0 ls0 ws0">Q3</div><div class="t m0 x4b hb y3e ff3 fs3 fc1 sc0 ls0 ws0">8050</div><div class="t m0 x4c hb y44 ff3 fs3 fc2 sc0 ls0 ws0">VCC</div><div class="t m0 x4d hb y3c ff3 fs3 fc1 sc0 ls0 ws0">D1</div><div class="t m0 x4e hb y45 ff3 fs3 fc1 sc0 ls0 ws0">1N41<span class="_ _c"></span>48</div><div class="t m0 x4f hb y3f ff3 fs3 fc1 sc0 ls0 ws0">1k</div><div class="t m0 x4f hb y40 ff3 fs3 fc1 sc0 ls0 ws0">R28</div><div class="t m0 x50 ha y46 ff2 fs3 fc1 sc0 ls0 ws0">至电<span class="_ _c"></span>加热棒</div><div class="t m0 x51 ha y47 ff3 fs3 fc1 sc0 ls0 ws0">I/0<span class="_ _f"></span><span class="ff2">至单<span class="_ _c"></span>片机<span class="_ _10"> </span>口</span></div><div class="t m0 x4a hb y48 ff3 fs3 fc2 sc0 ls0 ws0">AC2<span class="_ _c"></span>20V N</div><div class="t m0 xe hb y49 ff3 fs3 fc2 sc0 ls0 ws0">AC2<span class="_ _c"></span>20V N</div><div class="t m0 x52 hb y4a ff3 fs3 fc0 sc0 ls0 ws0">1</div><div class="t m0 x52 hb y4b ff3 fs3 fc0 sc0 ls0 ws0">2</div><div class="t m0 x52 hb y4c ff3 fs3 fc0 sc0 ls0 ws0">3</div><div class="t m0 x50 hb y4d ff3 fs3 fc1 sc0 ls0 ws0">P1</div></div><div class="c x0 y1 w2 h2"><div class="t m0 x53 h5 y4e ff2 fs1 fc0 sc0 ls0 ws0">图<span class="_ _b"> </span><span class="ff1">4.5 </span>声音报警电路</div><div class="t m0 x2 h3 y4f ff4 fs0 fc0 sc0 ls0 ws0">4.1.4 <span class="ff2 sc1">单片机及按键电路设计</span></div><div class="t m0 x1 h3 y50 ff2 fs0 fc0 sc0 ls0 ws0">图<span class="_ _7"> </span><span class="ff1">4.6<span class="_ _7"> </span></span>为<span class="_ _2"></span>单<span class="_ _2"></span>片<span class="_ _2"></span>机<span class="_ _2"></span>及<span class="_ _2"></span>键<span class="_ _2"></span>盘<span class="_ _2"></span>电路<span class="_ _2"></span>的<span class="_ _2"></span>电<span class="_ _2"></span>路<span class="_ _2"></span>图<span class="_ _2"></span>，<span class="_ _2"></span>单<span class="_ _2"></span>片机<span class="_"> </span><span class="ff1">A<span class="_ _8"></span>T89S52<span class="_ _7"> </span><span class="ff2">的<span class="_ _2"></span>时<span class="_ _2"></span>钟引<span class="_ _2"></span>脚<span class="_ _2"></span>外<span class="_ _2"></span>接</span></span></div><div class="t m0 x2 h3 y51 ff1 fs0 fc0 sc0 ls0 ws0">12M<span class="_ _7"> </span><span class="ff2">晶振<span class="_ _2"></span>，<span class="_ _2"></span>作为<span class="_ _2"></span>单<span class="_ _2"></span>片机<span class="_ _2"></span>工作<span class="_ _2"></span>的<span class="_ _2"></span>时钟<span class="_ _2"></span>，<span class="_ _4"></span></span>EA<span class="_ _7"> </span><span class="ff2">端<span class="_ _2"></span>接高<span class="_ _2"></span>电平<span class="_ _2"></span>，<span class="_ _2"></span>表示<span class="_ _2"></span>使<span class="_ _2"></span>用片<span class="_ _2"></span>内程<span class="_ _2"></span>序<span class="_ _2"></span>存储</span></div><div class="t m0 x2 h3 y52 ff2 fs0 fc0 sc0 ls0 ws0">器。<span class="_ _2"></span><span class="ff1">RST<span class="_ _0"> </span></span>引<span class="_ _2"></span>脚接了<span class="_ _2"></span>上电复<span class="_ _2"></span>位电<span class="_ _2"></span>路，当<span class="_ _2"></span>系统上<span class="_ _2"></span>电时<span class="_ _2"></span>，上电复<span class="_ _2"></span>位电<span class="_ _2"></span>路会产<span class="_ _2"></span>生一个<span class="_ _2"></span>高</div><div class="t m0 x2 h3 y53 ff2 fs0 fc0 sc0 ls0 ws0">电平脉冲信号，使系统复位。</div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></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/62f1c1015425817ffc225dfd/bg3.jpg"><div class="c x4f y54 w5 hc"><div class="t m0 x54 hd y55 ff3 fs4 fc1 sc0 ls0 ws0">Y1</div><div class="t m0 x54 hd y56 ff3 fs4 fc1 sc0 ls0 ws0">12M</div><div class="t m0 x55 hd y57 ff3 fs4 fc1 sc0 ls0 ws0">C4</div><div class="t m0 x55 hd y58 ff3 fs4 fc1 sc0 ls0 ws0">22P</div><div class="t m0 x55 hd y59 ff3 fs4 fc1 sc0 ls0 ws0">C5</div><div class="t m0 x55 hd y5a ff3 fs4 fc1 sc0 ls0 ws0">22P</div><div class="t m0 x55 hd y5b ff3 fs4 fc1 sc0 ls0 ws0">C3</div><div class="t m0 x55 hd y5c ff3 fs4 fc1 sc0 ls0 ws0">10u<span class="_ _c"></span>F</div><div class="t m0 x56 hd y5d ff3 fs4 fc1 sc0 ls0 ws0">R7</div><div class="t m0 x56 hd y5e ff3 fs4 fc1 sc0 ls0 ws0">10K</div><div class="t m0 x57 hd y5f ff3 fs4 fc1 sc0 ls0 ws0">S1</div><div class="t m0 x57 hd y60 ff3 fs4 fc1 sc0 ls0 ws0">1</div><div class="t m0 x57 hd y61 ff3 fs4 fc1 sc0 ls0 ws0">S2</div><div class="t m0 x57 hd y62 ff3 fs4 fc1 sc0 ls0 ws0">1</div><div class="t m0 x57 hd y63 ff3 fs4 fc1 sc0 ls0 ws0">S3</div><div class="t m0 x57 hd y64 ff3 fs4 fc1 sc0 ls0 ws0">1</div><div class="t m0 x57 hd y65 ff3 fs4 fc1 sc0 ls0 ws0">S4</div><div class="t m0 x57 hd y66 ff3 fs4 fc1 sc0 ls0 ws0">1</div><div class="t m0 x58 hd y67 ff3 fs4 fc1 sc0 ls0 ws0">10K</div><div class="t m0 x58 hd y68 ff3 fs4 fc1 sc0 ls0 ws0">R8</div><div class="t m0 x58 hd y69 ff3 fs4 fc1 sc0 ls0 ws0">10K</div><div class="t m0 x58 hd y6a ff3 fs4 fc1 sc0 ls0 ws0">R9</div><div class="t m0 x59 hd y6b ff3 fs4 fc3 sc0 ls0 ws0">VCC</div><div class="t m0 x58 hd y6c ff3 fs4 fc1 sc0 ls0 ws0">10K</div><div class="t m0 x58 hd y6d ff3 fs4 fc1 sc0 ls0 ws0">R18</div><div class="t m0 x58 hd y6e ff3 fs4 fc1 sc0 ls0 ws0">10K</div><div class="t m0 x58 hd y6f ff3 fs4 fc1 sc0 ls0 ws0">R17</div><div class="t m0 x5a hd y70 ff3 fs4 fc2 sc0 ls0 ws0">VCC</div><div class="t m0 x5b hd y71 ff3 fs4 fc2 sc0 ls0 ws0">VCC</div><div class="t m0 x5c hd y72 ff3 fs4 fc2 sc0 ls0 ws0">VCC</div><div class="t m0 x5d hd y70 ff3 fs4 fc0 sc0 ls0 ws0">P1.0<span class="_ _c"></span>/T2</div><div class="t m0 x1 hd y72 ff3 fs4 fc0 sc0 ls0 ws0">1</div><div class="t m0 x5e hd y73 ff3 fs4 fc0 sc0 ls0 ws0">P1.1<span class="_ _c"></span>/T2E<span class="_ _c"></span>X</div><div class="t m0 x1 hd y74 ff3 fs4 fc0 sc0 ls0 ws0">2</div><div class="t m0 x47 hd y75 ff3 fs4 fc0 sc0 ls0 ws0">P1.2</div><div class="t m0 x1 hd y76 ff3 fs4 fc0 sc0 ls0 ws0">3</div><div class="t m0 x47 hd y77 ff3 fs4 fc0 sc0 ls0 ws0">P1.3</div><div class="t m0 x1 hd y78 ff3 fs4 fc0 sc0 ls0 ws0">4</div><div class="t m0 x47 hd y79 ff3 fs4 fc0 sc0 ls0 ws0">P1.4</div><div class="t m0 x1 hd y7a ff3 fs4 fc0 sc0 ls0 ws0">5</div><div class="t m0 x47 hd y7b ff3 fs4 fc0 sc0 ls0 ws0">P1.5</div><div class="t m0 x1 hd y4c ff3 fs4 fc0 sc0 ls0 ws0">6</div><div class="t m0 x47 hd y7c ff3 fs4 fc0 sc0 ls0 ws0">P1.6</div><div class="t m0 x1 hd y7d ff3 fs4 fc0 sc0 ls0 ws0">7</div><div class="t m0 x47 hd y7e ff3 fs4 fc0 sc0 ls0 ws0">P1.7</div><div class="t m0 x1 hd y7f ff3 fs4 fc0 sc0 ls0 ws0">8</div><div class="t m0 x5f hd y80 ff3 fs4 fc0 sc0 ls0 ws0">RST</div><div class="t m0 x60 hd y81 ff3 fs4 fc0 sc0 ls0 ws0">9</div><div class="t m0 x5f hd y7b ff3 fs4 fc0 sc0 ls0 ws0">P3.0<span class="_ _c"></span>/RxD</div><div class="t m0 x61 hd y4c ff3 fs4 fc0 sc0 ls0 ws0">10</div><div class="t m0 x5f hd y7c ff3 fs4 fc0 sc0 ls0 ws0">P3.1<span class="_ _c"></span>/TxD</div><div class="t m0 x61 hd y7d ff3 fs4 fc0 sc0 ls0 ws0">11</div><div class="t m0 x5f hd y7e ff3 fs4 fc0 sc0 ls0 ws0">P3.2<span class="_ _c"></span>/IN<span class="_ _c"></span>T0</div><div class="t m0 x61 hd y7f ff3 fs4 fc0 sc0 ls0 ws0">12</div><div class="t m0 x5f hd y82 ff3 fs4 fc0 sc0 ls0 ws0">P3.3<span class="_ _c"></span>/IN<span class="_ _c"></span>T1</div><div class="t m0 x61 hd y83 ff3 fs4 fc0 sc0 ls0 ws0">13</div><div class="t m0 x5f hd y84 ff3 fs4 fc0 sc0 ls0 ws0">P3.4<span class="_ _c"></span>/T0</div><div class="t m0 x61 hd y85 ff3 fs4 fc0 sc0 ls0 ws0">14</div><div class="t m0 x5f hd y86 ff3 fs4 fc0 sc0 ls0 ws0">P3.5<span class="_ _c"></span>/T1</div><div class="t m0 x61 hd y87 ff3 fs4 fc0 sc0 ls0 ws0">15</div><div class="t m0 x5f hd y23 ff3 fs4 fc0 sc0 ls0 ws0">P3.6<span class="_ _c"></span>/WR</div><div class="t m0 x61 hd y88 ff3 fs4 fc0 sc0 ls0 ws0">16</div><div class="t m0 x5f hd y89 ff3 fs4 fc0 sc0 ls0 ws0">P3.7<span class="_ _c"></span>/RD</div><div class="t m0 x61 hd y8a ff3 fs4 fc0 sc0 ls0 ws0">17</div><div class="t m0 x5f hd y8b ff3 fs4 fc0 sc0 ls0 ws0">XT<span class="_ _c"></span>AL2</div><div class="t m0 x61 hd y8c ff3 fs4 fc0 sc0 ls0 ws0">18</div><div class="t m0 x5f hd y8d ff3 fs4 fc0 sc0 ls0 ws0">XT<span class="_ _c"></span>AL1</div><div class="t m0 x61 hd y57 ff3 fs4 fc0 sc0 ls0 ws0">19</div><div class="t m0 x5f hd y8e ff3 fs4 fc0 sc0 ls0 ws0">VSS</div><div class="t m0 x61 hd y8f ff3 fs4 fc0 sc0 ls0 ws0">20</div><div class="t m0 x5d hd y84 ff3 fs4 fc0 sc0 ls0 ws0">P2.0<span class="_ _c"></span>/A8</div><div class="t m0 x1 hd y85 ff3 fs4 fc0 sc0 ls0 ws0">21</div><div class="t m0 x5d hd y86 ff3 fs4 fc0 sc0 ls0 ws0">P2.1<span class="_ _c"></span>/A9</div><div class="t m0 x1 hd y87 ff3 fs4 fc0 sc0 ls0 ws0">22</div><div class="t m0 x2 hd y23 ff3 fs4 fc0 sc0 ls0 ws0">P2.2<span class="_ _c"></span>/A10</div><div class="t m0 x1 hd y88 ff3 fs4 fc0 sc0 ls0 ws0">23</div><div class="t m0 x2 hd y89 ff3 fs4 fc0 sc0 ls0 ws0">P2.3<span class="_ _c"></span>/A11</div><div class="t m0 x1 hd y8a ff3 fs4 fc0 sc0 ls0 ws0">24</div><div class="t m0 x2 hd y90 ff3 fs4 fc0 sc0 ls0 ws0">P2.4<span class="_ _c"></span>/A12</div><div class="t m0 x1 hd y91 ff3 fs4 fc0 sc0 ls0 ws0">25</div><div class="t m0 x2 hd y92 ff3 fs4 fc0 sc0 ls0 ws0">P2.5<span class="_ _c"></span>/A13</div><div class="t m0 x1 hd y93 ff3 fs4 fc0 sc0 ls0 ws0">26</div><div class="t m0 x2 hd y94 ff3 fs4 fc0 sc0 ls0 ws0">P2.6<span class="_ _c"></span>/A14</div><div class="t m0 x1 hd y95 ff3 fs4 fc0 sc0 ls0 ws0">27</div><div class="t m0 x2 hd y8e ff3 fs4 fc0 sc0 ls0 ws0">P2.7<span class="_ _c"></span>/A15</div><div class="t m0 x1 hd y8f ff3 fs4 fc0 sc0 ls0 ws0">28</div><div class="t m0 x5f hd y73 ff3 fs4 fc0 sc0 ls0 ws0">PSE<span class="_ _c"></span>N</div><div class="t m0 x61 hd y74 ff3 fs4 fc0 sc0 ls0 ws0">29</div><div class="t m0 x5f hd y75 ff3 fs4 fc0 sc0 ls0 ws0">AL<span class="_ _c"></span>E</div><div class="t m0 x61 hd y76 ff3 fs4 fc0 sc0 ls0 ws0">30</div><div class="t m0 x5f hd y70 ff3 fs4 fc0 sc0 ls0 ws0">EA<span class="_ _c"></span>/VPP</div><div class="t m0 x61 hd y72 ff3 fs4 fc0 sc0 ls0 ws0">31</div><div class="t m0 x62 hd y96 ff3 fs4 fc0 sc0 ls0 ws0">P0.7<span class="_ _c"></span>/AD7</div><div class="t m0 x1 hd y97 ff3 fs4 fc0 sc0 ls0 ws0">32</div><div class="t m0 x62 hd y98 ff3 fs4 fc0 sc0 ls0 ws0">P0.6<span class="_ _c"></span>/AD6</div><div class="t m0 x1 hd y99 ff3 fs4 fc0 sc0 ls0 ws0">33</div><div class="t m0 x62 hd y9a ff3 fs4 fc0 sc0 ls0 ws0">P0.5<span class="_ _c"></span>/AD5</div><div class="t m0 x1 hd y9b ff3 fs4 fc0 sc0 ls0 ws0">34</div><div class="t m0 x62 hd y9c ff3 fs4 fc0 sc0 ls0 ws0">P0.4<span class="_ _c"></span>/AD4</div><div class="t m0 x1 hd y58 ff3 fs4 fc0 sc0 ls0 ws0">35</div><div class="t m0 x62 hd y9d ff3 fs4 fc0 sc0 ls0 ws0">P0.3<span class="_ _c"></span>/AD3</div><div class="t m0 x1 hd y9e ff3 fs4 fc0 sc0 ls0 ws0">36</div><div class="t m0 x62 hd y8b ff3 fs4 fc0 sc0 ls0 ws0">P0.2<span class="_ _c"></span>/AD2</div><div class="t m0 x1 hd y8c ff3 fs4 fc0 sc0 ls0 ws0">37</div><div class="t m0 x62 hd y8d ff3 fs4 fc0 sc0 ls0 ws0">P0.1<span class="_ _c"></span>/AD1</div><div class="t m0 x1 hd y57 ff3 fs4 fc0 sc0 ls0 ws0">38</div><div class="t m0 x62 hd y9f ff3 fs4 fc0 sc0 ls0 ws0">P0.0<span class="_ _c"></span>/AD0</div><div class="t m0 x1 hd ya0 ff3 fs4 fc0 sc0 ls0 ws0">39</div><div class="t m0 x63 hd y71 ff3 fs4 fc0 sc0 ls0 ws0">VCC</div><div class="t m0 x1 hd y5a ff3 fs4 fc0 sc0 ls0 ws0">40</div><div class="t m0 x64 hd ya1 ff3 fs4 fc1 sc0 ls0 ws0">U1</div><div class="t m0 x64 hd ya2 ff3 fs4 fc1 sc0 ls0 ws0">AT<span class="_ _c"></span>89C5<span class="_ _c"></span>1</div></div><div class="c x0 y1 w2 h2"><div class="t m0 x20 h3 ya3 ff2 fs0 fc0 sc0 ls0 ws0">图<span class="_ _0"> </span><span class="ff3">4.6 </span>单片机及键盘电路电路图</div><div class="t m0 x1 h3 ya4 ff2 fs0 fc0 sc0 ls0 ws0">键盘<span class="_ _2"></span>是标<span class="_ _2"></span>准的<span class="_ _2"></span>输入<span class="_ _2"></span>设备<span class="_ _2"></span>，实<span class="_ _2"></span>现键<span class="_ _2"></span>盘有<span class="_ _2"></span>两种<span class="_ _2"></span>方案<span class="_ _2"></span>：一<span class="_ _2"></span>是采<span class="_ _2"></span>用现<span class="_ _2"></span>有的<span class="_ _2"></span>一些<span class="_ _2"></span>芯片</div><div class="t m0 x2 h3 ya5 ff2 fs0 fc0 sc0 ls0 ws0">实现键盘扫<span class="_ _2"></span>描，如<span class="_ _0"> </span><span class="ff3">8279, CH451, LMC9768<span class="_"> </span></span>等，还有就是用软件实现<span class="_ _2"></span>键盘扫描。</div><div class="t m0 x2 h3 ya6 ff2 fs0 fc0 sc0 ls0 ws0">使用现<span class="_ _2"></span>成的芯片可<span class="_ _2"></span>以节省<span class="_ _7"> </span><span class="ff3">CPU<span class="_ _0"> </span></span>的<span class="_ _2"></span>开销，但<span class="_ _2"></span>增加了成本<span class="_ _2"></span>，而用软<span class="_ _2"></span>件实现具有<span class="_ _2"></span>较强</div><div class="t m0 x2 h3 ya7 ff2 fs0 fc0 sc0 ls0 ws0">的灵活<span class="_ _2"></span>性，也只需<span class="_ _2"></span>要很少的<span class="_ _7"> </span><span class="ff3">CPU<span class="_ _7"> </span></span>开销，<span class="_ _2"></span>可以节省<span class="_ _2"></span>开发成本。<span class="_ _2"></span>本文便使<span class="_ _2"></span>用软件实</div><div class="t m0 x2 h3 ya8 ff2 fs0 fc0 sc0 ls0 ws0">现键盘的扫描。</div><div class="t m0 x2 h3 ya9 ff3 fs0 fc0 sc0 ls0 ws0"> <span class="_ _2"></span> <span class="_ _2"></span><span class="ff2">常<span class="_ _2"></span>见的键<span class="_ _2"></span>盘可<span class="_ _2"></span>分为独<span class="_ _2"></span>立按键<span class="_ _2"></span>式键盘<span class="_ _2"></span>和行列<span class="_ _2"></span>扫描<span class="_ _2"></span>式键盘<span class="_ _2"></span>。独立<span class="_ _2"></span>按键<span class="_ _2"></span>式键盘应<span class="_ _2"></span>用</span></div><div class="t m0 x2 h3 yaa ff2 fs0 fc0 sc0 ls0 ws0">在<span class="_ _2"></span>需要<span class="_ _2"></span>少<span class="_ _2"></span>量<span class="_ _2"></span>按键<span class="_ _2"></span>的<span class="_ _2"></span>情<span class="_ _2"></span>况，<span class="_ _2"></span>按<span class="_ _2"></span>键<span class="_ _2"></span>和单<span class="_ _2"></span>片<span class="_ _2"></span>机<span class="_ _2"></span>的<span class="_ _a"> </span><span class="ff3">I/O<span class="_ _7"> </span></span>口<span class="_ _2"></span>线直<span class="_ _2"></span>接<span class="_ _2"></span>连<span class="_ _2"></span>接。<span class="_ _2"></span>而<span class="_ _2"></span>行<span class="_ _2"></span>列扫<span class="_ _2"></span>描<span class="_ _2"></span>式<span class="_ _2"></span>键</div><div class="t m0 x2 h3 yab ff2 fs0 fc0 sc0 ls0 ws0">盘用<span class="_ _2"></span>在按<span class="_ _2"></span>键需<span class="_ _2"></span>求较<span class="_ _2"></span>多的<span class="_ _2"></span>情形<span class="_ _2"></span>下。<span class="_ _2"></span><span class="ff5">考<span class="_ _2"></span>虑</span>到<span class="_ _9"></span>热<span class="_ _2"></span>水控<span class="_ _2"></span>制器<span class="_ _2"></span>只需<span class="_ _2"></span>要高<span class="_ _2"></span><span class="ff5">限</span>加<span class="_ _2"></span>、高<span class="_ _2"></span><span class="ff5">限减<span class="_ _2"></span></span>、低</div><div class="t m0 x2 h3 yac ff5 fs0 fc0 sc0 ls0 ws0">限<span class="ff2">加、低</span>限减四<span class="ff2">个按键 ，所以采用独立按键式键盘。</span></div><div class="t m0 x65 h3 yad ff2 fs0 fc0 sc0 ls0 ws0">理<span class="_ _2"></span><span class="ff5">论</span>上<span class="_ _2"></span>当<span class="_ _2"></span>按<span class="_ _2"></span>键按<span class="_ _2"></span>下<span class="_ _2"></span><span class="ff5">或<span class="_ _2"></span>弹<span class="_ _2"></span></span>起时<span class="_ _2"></span>，<span class="_ _2"></span>可<span class="_ _2"></span>以相<span class="_ _2"></span>应<span class="_ _2"></span>的<span class="_ _2"></span>产生<span class="_ _2"></span>低<span class="_ _2"></span>电<span class="_ _2"></span>平<span class="_ _2"></span><span class="ff5">或<span class="_ _2"></span></span>高电<span class="_ _2"></span>平<span class="_ _2"></span>，<span class="_ _2"></span>但实<span class="_ _2"></span><span class="ff5">际<span class="_ _2"></span></span>并</div><div class="t m0 x2 h3 yae ff5 fs0 fc0 sc0 ls0 ws0">非<span class="ff2">如<span class="_ _2"></span>此。<span class="_ _2"></span>键盘<span class="_ _2"></span>按键<span class="_ _2"></span>一般<span class="_ _2"></span>都采<span class="_ _2"></span>用<span class="_ _2"></span></span>触<span class="ff2">点<span class="_ _2"></span>式按<span class="_ _2"></span>键开<span class="_ _2"></span></span>关<span class="ff2">。<span class="_ _2"></span>当按<span class="_ _2"></span>键</span>被<span class="_ _2"></span><span class="ff2">按下<span class="_ _2"></span></span>或释<span class="_ _2"></span>放<span class="ff2">时<span class="_ _2"></span>，按<span class="_ _2"></span>键</span></div><div class="t m0 x2 h3 yaf ff5 fs0 fc0 sc0 ls0 ws0">触<span class="ff2">点<span class="_ _2"></span>的</span>弹<span class="_ _2"></span><span class="ff2">性会<span class="_ _2"></span>产生<span class="_ _2"></span></span>抖<span class="_ _2"></span><span class="ff2">动现<span class="_ _2"></span></span>象<span class="ff2">。<span class="_ _2"></span></span>即<span class="ff2">当<span class="_ _2"></span>按键<span class="_ _2"></span>按下<span class="_ _2"></span>时，<span class="_ _2"></span></span>触<span class="ff2">点<span class="_ _2"></span></span>不<span class="ff2">会<span class="_ _2"></span></span>迅速<span class="_ _2"></span><span class="ff2">可</span>靠<span class="_ _2"></span>地<span class="ff2">接<span class="_ _2"></span>通，<span class="_ _2"></span>当</span></div><div class="t m0 x2 h3 yb0 ff2 fs0 fc0 sc0 ls0 ws0">按键<span class="_ _2"></span><span class="ff5">释放<span class="_ _2"></span></span>时，<span class="_ _2"></span><span class="ff5">触</span>点<span class="_ _2"></span>也<span class="_ _2"></span><span class="ff5">不</span>会<span class="_ _2"></span>立<span class="ff5">即<span class="_ _2"></span>断</span>开<span class="_ _2"></span>，而<span class="_ _2"></span>是要<span class="_ _2"></span>经过<span class="_ _2"></span>一段<span class="_ _2"></span>时<span class="ff5">间<span class="_ _2"></span></span>的<span class="ff5">抖<span class="_ _2"></span></span>动<span class="ff5">才<span class="_ _2"></span></span>能<span class="ff5">稳<span class="_ _2"></span></span>定下<span class="_ _2"></span>来<span class="_ _9"></span>，</div><div class="t m0 x2 h3 yb1 ff2 fs0 fc0 sc0 ls0 ws0">按键<span class="ff5">材料不</span>同，<span class="ff5">抖</span>动时<span class="ff5">间</span>也<span class="ff5">各不</span>相同。</div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></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/62f1c1015425817ffc225dfd/bg4.jpg"><div class="c x0 y1 w2 h2"><div class="t m0 x66 h3 yb2 ff1 fs0 fc0 sc0 ls0 ws0"> <span class="ff2">图<span class="_ _0"> </span></span>4-7 <span class="ff2">按键<span class="ff5">抖</span>动示<span class="ff5">意</span>图</span></div><div class="t m0 x1 h3 yb3 ff2 fs0 fc0 sc0 ls0 ws0">一<span class="ff5">次完整</span>的按键过程，<span class="ff5">包含</span>以下<span class="ff5">几</span>个<span class="ff5">阶</span>段<span class="ff1">:</span>如图<span class="_ _0"> </span><span class="ff1">4-7<span class="_ _0"> </span></span>所示。</div><div class="t m0 x1 h3 yb4 ff1 fs0 fc0 sc0 ls0 ws0">1) <span class="ff2">等<span class="ff5">待阶</span>段</span>:<span class="ff2">此时按键<span class="ff5">尚未</span>按下，<span class="ff5">处</span>于<span class="ff5">空闲阶</span>段；</span></div><div class="t m0 x65 h3 yb5 ff1 fs0 fc0 sc0 ls0 ws0">2) <span class="ff2">闭<span class="ff5">合抖</span>动<span class="ff5">阶</span>段<span class="_ _2"></span></span>:<span class="ff2">此时键<span class="ff5">刚刚</span>按下，但信号<span class="ff5">处</span>于<span class="ff5">抖</span>动<span class="ff5">状态</span>，系统在<span class="ff5">检测</span>时应</span></div><div class="t m0 x2 h3 yb6 ff2 fs0 fc0 sc0 ls0 ws0">消<span class="ff5">抖延</span>时，约<span class="_ _0"> </span><span class="ff1">5ms<span class="_ _0"> </span></span>到<span class="_ _0"> </span><span class="ff1">20ms</span>；</div><div class="t m0 x65 h3 yb7 ff1 fs0 fc0 sc0 ls0 ws0">3) <span class="ff2">有<span class="ff5">效</span>闭<span class="ff5">合阶</span>段<span class="_ _2"></span></span>:<span class="ff2">此时<span class="ff5">抖</span>动<span class="ff5">己</span>经<span class="ff5">结束</span>，一个有<span class="ff5">效</span>按键动作<span class="ff5">己</span>经产生，系统应</span></div><div class="t m0 x2 h3 yb8 ff5 fs0 fc0 sc0 ls0 ws0">该<span class="ff2">在此时</span>执<span class="ff2">行按键功能，</span>或将<span class="ff2">按键</span>编<span class="ff2">码</span>记录<span class="ff2">下来，</span>待<span class="ff2">键</span>弹<span class="ff2">起时再</span>执<span class="ff2">行其功能；</span></div><div class="t m0 x65 h3 yb9 ff1 fs0 fc0 sc0 ls0 ws0">4) <span class="ff5">释放抖<span class="ff2">动</span>阶<span class="ff2">段<span class="_ _2"></span></span></span>:<span class="ff5">许<span class="ff2">多时</span>候编<span class="ff2">程</span>人员<span class="ff2">并</span>不<span class="ff2">在此时消</span>抖延<span class="ff2">时，但最</span>好<span class="ff2">也</span>执<span class="ff2">行一</span></span></div><div class="t m0 x2 h3 yba ff5 fs0 fc0 sc0 ls0 ws0">次<span class="ff2">消</span>抖延<span class="ff2">时，以</span>防<span class="ff2">止</span>误操<span class="ff2">作；</span></div><div class="t m0 x65 h3 ybb ff1 fs0 fc0 sc0 ls0 ws0">5) <span class="ff2">有<span class="ff5">效释放阶</span>段<span class="_ _2"></span></span>:<span class="ff5">若<span class="ff2">设计要求在按键</span>抬<span class="ff2">起时</span>才执<span class="ff2">行功能，</span>则<span class="ff2">应当在此时</span>进<span class="ff2">行</span></span></div><div class="t m0 x2 h3 ybc ff2 fs0 fc0 sc0 ls0 ws0">按键功能的<span class="ff5">处</span>理。</div><div class="t m0 x65 h3 ybd ff2 fs0 fc0 sc0 ls0 ws0">软<span class="_ _2"></span>件上<span class="_ _2"></span>对<span class="_ _2"></span>闭<span class="_ _2"></span><span class="ff5">合<span class="_ _2"></span>阶</span>段<span class="_ _2"></span>的<span class="_ _2"></span><span class="ff5">抖<span class="_ _2"></span></span>动一<span class="_ _2"></span>般<span class="_ _2"></span>采<span class="_ _2"></span><span class="ff5">取<span class="_ _2"></span>延</span>时<span class="_ _2"></span>再<span class="_ _2"></span><span class="ff5">次<span class="_ _2"></span>确认<span class="_ _2"></span></span>按<span class="_ _2"></span>键<span class="_ _2"></span>是<span class="_ _2"></span><span class="ff5">否</span>按<span class="_ _2"></span>下<span class="_ _2"></span>的<span class="_ _2"></span>方式<span class="_ _2"></span>消<span class="_ _2"></span><span class="ff5">除</span></div><div class="t m0 x2 h3 ybe ff5 fs0 fc0 sc0 ls0 ws0">抖<span class="ff2">动。</span></div><div class="t m0 x67 h3 ybf ff2 fs0 fc0 sc0 ls0 ws0">如上图所示，<span class="ff5">完</span>成系统的最高温度和最低温度的高低<span class="ff5">调整</span>的<span class="ff5">四</span>个按键分别</div><div class="t m0 x2 h3 yc0 ff2 fs0 fc0 sc0 ls0 ws0">加上<span class="_ _2"></span><span class="ff5">拉</span>电<span class="ff5">阻<span class="_ _2"></span></span>接到<span class="_ _2"></span>单片机<span class="_ _2"></span>的<span class="_ _1"> </span><span class="ff1">P1.1-P1.4<span class="_ _0"> </span></span>口上<span class="_ _2"></span>，<span class="ff5">供<span class="_ _2"></span></span>单片机<span class="_ _2"></span><span class="ff5">查询<span class="_ _2"></span></span>，当<span class="ff5">没<span class="_ _2"></span></span>有按<span class="_ _2"></span>键按下<span class="_ _2"></span>时<span class="_ _9"></span>，</div><div class="t m0 x2 h3 yc1 ff2 fs0 fc0 sc0 ls0 ws0">单<span class="_ _2"></span>片机<span class="_ _7"> </span><span class="ff1">I/<span class="_ _2"></span>O<span class="_ _0"> </span></span>口<span class="_ _2"></span>输<span class="_ _2"></span>入高<span class="_ _2"></span>电平<span class="_ _2"></span>，<span class="_ _2"></span>当有<span class="_ _2"></span>按<span class="_ _2"></span>键按<span class="_ _2"></span>下时<span class="_ _2"></span>，<span class="_ _2"></span>对应<span class="_ _2"></span>的<span class="_ _2"></span>单片<span class="_ _2"></span>机端<span class="_ _2"></span>口<span class="_ _2"></span><span class="ff5">变<span class="_ _2"></span></span>为低<span class="_ _2"></span>电<span class="_ _2"></span>平，</div><div class="t m0 x2 h3 yc2 ff2 fs0 fc0 sc0 ls0 ws0">单片机通过<span class="ff5">检测</span>这种电平的<span class="ff5">变化确</span>定按键的<span class="ff5">状态</span>。</div><div class="t m0 x2 he yc3 ff4 fs5 fc0 sc0 ls0 ws0">4.2 <span class="ff2 sc1">软件系统设计</span></div><div class="t m0 x2 h3 yc4 ff4 fs0 fc0 sc0 ls0 ws0">4.2.1 <span class="ff2 sc1">系统程序流程图</span></div><div class="t m0 x68 h3 yc5 ff2 fs0 fc0 sc0 ls0 ws0">系统程序流程图如图<span class="_ _0"> </span><span class="ff1">4.8<span class="_ _0"> </span></span>所示。</div></div></div><div class="pi" data-data='{"ctm":[1.611850,0.000000,0.000000,1.611850,0.000000,0.000000]}'></div></div>