芯片管脚定义基础知识

缘份

<p class="MsoNormal" align="left" style="MARGIN: 5.2pt 0cm; LINE-HEIGHT: 150%; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><b><span style="FONT-SIZE: 9pt; COLOR: #1d4f96; LINE-HEIGHT: 150%; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-font-kerning: 0pt;">在从事固网通讯终端开发的过程中，作为一个研发工程师,经常会定义一些Ｉ／Ｏ口，但是说实话我记刚开始时真的脑子里没有什么概念，后来我们这边的软件工程师给了我以下资料，经过仔细研究了一下，就明白了，所以说作为一个工程师来说，不懂这些东西，会被人笑话的．</span></b></p><p class="MsoNormal" align="left" style="MARGIN: 5.2pt 0cm; LINE-HEIGHT: 150%; TEXT-ALIGN: left; mso-pagination: widow-orphan;"><b><span style="FONT-SIZE: 9pt; COLOR: #1d4f96; LINE-HEIGHT: 150%; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-font-kerning: 0pt;"></span></b></p><b><span style="FONT-SIZE: 9pt; COLOR: #1d4f96; LINE-HEIGHT: 150%; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-font-kerning: 0pt;"><font color="#000000"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">输入口（</span><span lang="EN-US"><font face="Times New Roman">Input</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">）</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　输入口其实可以理解为一个对地电阻和对</span><span lang="EN-US"><font face="Times New Roman">VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">电阻均为无穷大的端口，它的状态完全由外部电路决定。此脚不用时不能悬空，视工作情况要么接地要么到</span><span lang="EN-US"><font face="Times New Roman">VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">。</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman" size="3">&nbsp;</font></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">输出口（</span><span lang="EN-US"><font face="Times New Roman">Output</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">）</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　输出口可由程序设定为输出高或输出低，在负载范围内，输出高时的电压约等于</span><span lang="EN-US"><font face="Times New Roman">VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">，输出低时的电压约等于</span><span lang="EN-US"><font face="Times New Roman">VSS</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">。此脚不用时可悬空。</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman" size="3">&nbsp;</font></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">有内部上拉的输入口（</span><span lang="EN-US"><font face="Times New Roman">ull-high</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">）</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　有内部上拉的输入口相当于该输入口在芯片内部接了一个</span><span lang="EN-US"><font face="Times New Roman">150K</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">左右的电阻到</span><span lang="EN-US"><font face="Times New Roman">VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">。因此，与普通输入口相比，有内部上拉的输入口在外围悬空的情况下测量的电压近似于</span><span lang="EN-US"><font face="Times New Roman">VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">（不用时可悬空），而普通输入口在外围悬空的情况下测量的电压是不确定的，在</span><span lang="EN-US"><font face="Times New Roman">VSS~VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">之间变化，实际运用时是不能悬空的。</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman" size="3">&nbsp;</font></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">开漏输出（</span><span lang="EN-US"><font face="Times New Roman">Open-dnain</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">）</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　开漏输出的输出口特性如下：输出低时对</span><span lang="EN-US"><font face="Times New Roman">VSS</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">阻抗极低，在负载范围内近似于</span><span lang="EN-US"><font face="Times New Roman">VSS</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">；输出高时对</span><span lang="EN-US"><font face="Times New Roman">VSS</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">和</span><span lang="EN-US"><font face="Times New Roman">VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">阻抗视为无穷大，输出电压取决于外部电路提供的电压（最大为芯片极限存受电压）。</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman" size="3">&nbsp;</font></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US"><font face="Times New Roman">I/O</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">口</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　顾名思义同一脚即是输入口又是输出口，在不同的时候是不同的状态，视工作情况考虑外部电路；此脚有输入状态，所以不用时不能悬空，也不能直接接地或接</span><span lang="EN-US"><font face="Times New Roman">VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">，需通过</span><span lang="EN-US"><font face="Times New Roman">47K</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">以上的电阻上拉到</span><span lang="EN-US"><font face="Times New Roman">VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">或下拉到地。</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman" size="3">&nbsp;</font></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">如何准确判断输入</span><span lang="EN-US"><font face="Times New Roman">/</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">输出状态</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　下面通过一个电阻就可以准确判断出</span><span lang="EN-US"><font face="Times New Roman">I/O</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的输入</span><span lang="EN-US"><font face="Times New Roman">/</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">输出状态。请参考下表：</span><font face="Times New Roman">
                                                        </font></font></p><div align="center"><table class="MsoNormalTable" cellspacing="0" cellpadding="0" width="98%" border="0" style="BACKGROUND: #cccccc; WIDTH: 98%; BORDER-COLLAPSE: collapse; mso-padding-alt: 2.25pt 2.25pt 2.25pt 2.25pt;"><tbody><tr style="mso-yfti-irow: 0; mso-yfti-firstrow: yes;"><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: #f0f0f0; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">&nbsp;</font></span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: #f0f0f0; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">悬空</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: #f0f0f0; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">10K</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">电阻上拉到</span><span lang="EN-US"><font face="Times New Roman">VDD</font></span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: #f0f0f0; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><font face="Times New Roman">10K</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">电阻下拉到</span><span lang="EN-US"><font face="Times New Roman">VSS</font></span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: #f0f0f0; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">测试结果</span></p></td></tr><tr style="mso-yfti-irow: 1;"><td rowspan="4" style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">待测</span><span lang="EN-US"><font face="Times New Roman">I/O</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">电压</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">高</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">高</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">高</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">输出高</span></p></td></tr><tr style="mso-yfti-irow: 2;"><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">低</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">低</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">低</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">输出低</span></p></td></tr><tr style="mso-yfti-irow: 3;"><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">不定</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">高</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">低</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">普通输入</span></p></td></tr><tr style="mso-yfti-irow: 4; mso-yfti-lastrow: yes;"><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">高</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">高</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">低</span></p></td><td style="BORDER-RIGHT: #ece9d8; PADDING-RIGHT: 2.25pt; BORDER-TOP: #ece9d8; PADDING-LEFT: 2.25pt; BACKGROUND: white; PADDING-BOTTOM: 2.25pt; BORDER-LEFT: #ece9d8; PADDING-TOP: 2.25pt; BORDER-BOTTOM: #ece9d8;"><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">内部上拉</span></p></td></tr></tbody></table></div><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman" size="3">&nbsp;</font></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US"><font face="Times New Roman">I/O</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的内部保护</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　</span><span lang="EN-US"><font face="Times New Roman">I/O</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">一般都有内部保护电路，均采用二极管钳位保护，保证</span><span lang="EN-US"><font face="Times New Roman">I/O</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的电压不超过</span><span lang="EN-US"><font face="Times New Roman">VDD+0.7V</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">且不低于</span><span lang="EN-US"><font face="Times New Roman">VSS-0.7V,</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">确保</span><span lang="EN-US"><font face="Times New Roman">I/O</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">不因外部一定的电压而受到损伤。</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman" size="3">&nbsp;</font></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><font size="3">应用注意事项</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US"><font face="Times New Roman">§&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">所有输入口均不能悬空（内部上拉的输入口除外），必须通过外部电路接上稳定的高或低电位，否则会导致</span><span lang="EN-US"><font face="Times New Roman">MCU</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的耗电剧增或工作状态的变化。</span><font face="Times New Roman">
                                                        </font></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US"><font face="Times New Roman">§&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">硬件电路设计中应确保各脚的电压不超过</span><span lang="EN-US"><font face="Times New Roman">VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">且不低于</span><span lang="EN-US"><font face="Times New Roman">VSS</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">，否则将不仅会使</span><span lang="EN-US"><font face="Times New Roman">MCU</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">电流增大且又极易损坏芯片。</span><font face="Times New Roman">
                                                        </font></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span lang="EN-US"><font face="Times New Roman">§&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">芯片外围电路设计时必须确保芯片的供电电压在其允许范围之内。</span><font face="Times New Roman">
                                                        </font></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman" size="3">&nbsp;</font></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;"><font size="3">关于单片机高、低电位的判断</font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><font size="3"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">　　单片机输入口读取高、低电平的判断与芯片供电的</span><span lang="EN-US"><font face="Times New Roman">VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">有直接关系，</span><span lang="EN-US"><font face="Times New Roman">VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">不同，判断高、低的临界电压值也不一样。根据</span><span lang="EN-US"><font face="Times New Roman">IC</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">资料</span><span lang="EN-US"><font face="Times New Roman">,≥2/3VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的电压</span><span lang="EN-US"><font face="Times New Roman">MCU</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">判断为高</span><span lang="EN-US"><font face="Times New Roman">,</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">而</span><span lang="EN-US"><font face="Times New Roman">≤1/3VDD</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的电压值</span><span lang="EN-US"><font face="Times New Roman">MCU</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">判断为低</span><span lang="EN-US"><font face="Times New Roman">,</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">中间有一定的模糊区，而实际应用的经验告诉我们</span><span lang="EN-US"><font face="Times New Roman">,</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">单片机读到高比较容易而不容易读到低</span><span lang="EN-US"><font face="Times New Roman">,</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">一般</span><span lang="EN-US"><font face="Times New Roman">&lt;0.7V</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: &quot;Times New Roman&quot;; mso-hansi-font-family: &quot;Times New Roman&quot;;">的电压才可以准确读到低</span></font></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"></p></span></font></span></b><span style="FONT-SIZE: 8pt; COLOR: #656565; FONT-FAMILY: 宋体; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial; mso-bidi-font-family: Arial; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;"></span>