136 lines
7.9 KiB
HTML
136 lines
7.9 KiB
HTML
<?xml version="1.0" encoding="utf-8"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns:MadCap="http://www.madcapsoftware.com/Schemas/MadCap.xsd" MadCap:lastBlockDepth="6" MadCap:lastHeight="94" MadCap:lastWidth="853" MadCap:disableMasterStylesheet="true" MadCap:tocPath="" MadCap:InPreviewMode="false" MadCap:PreloadImages="false" MadCap:RuntimeFileType="Topic" MadCap:TargetType="WebHelp" lang="en-us" xml:lang="en-us" MadCap:PathToHelpSystem="../../../" MadCap:HelpSystemFileName="Default.xml" MadCap:SearchType="Stem">
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<head><title>PULSIN</title>
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<link href="../../SkinSupport/MadCap.css" rel="stylesheet" />
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<link href="../../Resources/Stylesheets/BSE_Help.css" rel="stylesheet" />
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<script src="../../SkinSupport/MadCapAll.js" type="text/javascript">
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</script>
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</head>
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<body>
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<h1 class="code">PULSIN</h1>
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<div class="ImagePlusCaption">
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<div class="Col2">
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<p>
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<img src="../../graphics/pgm_icon1.gif" border="0" alt="BS1 icon" title="BS1 icon" />
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<img src="../../graphics/pgm_icon2.gif" border="0" alt="BS2 icon" title="BS2 icon" />
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<img src="../../graphics/pgm_icon2e.gif" border="0" alt="BS2e icon" title="BS2e icon" />
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<img src="../../graphics/pgm_icon2sx.gif" border="0" alt="BS2sx icon" title="BS2sx icon" />
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<img src="../../graphics/pgm_icon2p.gif" border="0" alt="BS2p icon" title="BS2p icon" />
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<img src="../../graphics/pgm_icon2pe.gif" border="0" alt="BS2pe icon" title="BS2pe icon" />
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<img src="../../graphics/pgm_icon2px.gif" border="0" alt="BS2px icon" title="BS2px icon" />
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</p>
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</div>
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<p style="text-align: right;"><a href="../ExampleTopics/PulsinEx.htm" target="" title="" alt="" class="MCXref_0">PULSIN Example</a>
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</p>
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<p> </p>
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</div>
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<p class="clear"> </p>
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<p> </p>
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<p class="PlainText">Syntax: <span class="keyword_in_text">PULSIN</span> <![CDATA[ ]]><i>Pin</i>,<i> State</i>,<i> Variable</i></p>
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<h2>Function</h2>
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<p class="PlainText">Measure the width of a pulse on <i>Pin</i> described by <i>State</i> and store the
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result in <i>Variable</i>.
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</p>
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<ul>
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<li value="1"><b><i>Pin</i></b> is a variable/constant/expression* (0 - 15) that specifies
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the I/O pin to use. This pin will be set to input mode.</li>
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<li value="2"><b><i>State</i></b> is a variable/constant/expression* (0 - 1) that specifies
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whether the pulse to be measured is low (0) or high (1). A low pulse begins
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with a 1-to-0 transition and a high pulse begins with a 0-to-1 transition.</li>
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<li value="3"><b><i>Variable</i></b> is a variable (usually a word) in which the measured
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pulse duration will be stored. The unit of time for <i>Variable</i> is
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described below.</li>
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</ul>
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<p class="PlainText">*<img src="../../graphics/bs1note.gif" style="vertical-align: super;" /> Note: expressions are not allowed as arguments on the BS1. The range
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of the <i>Pin</i> argument on the BS1 is 0–7.</p>
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<h2>Quick Facts</h2>
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<table width="100%" cellpadding="4" cellspacing="0" border="1">
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<tr align="center" bgcolor="#CFCFCF">
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<td width="16%"> </td>
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<td width="12%">BS1</td>
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<td width="12%">BS2</td>
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<td width="12%">BS2e</td>
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<td width="12%">BS2sx</td>
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<td width="12%">BS2p</td>
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<td width="12%">BS2pe</td>
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<td width="12%">BS2px</td>
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</tr>
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<tr align="center">
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<td bgcolor="#CFCFCF">Units in <i>Variable</i></td>
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<td>10 µs</td>
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<td>2 µs</td>
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<td>2 µs</td>
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<td>0.8 µs</td>
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<td>0.75 µs</td>
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<td>2 µs</td>
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<td>0.81 µs</td>
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</tr>
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<tr align="center">
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<td align="center" bgcolor="#CFCFCF">Maximum pulse width</td>
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<td>655.35 ms</td>
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<td>131.07 ms</td>
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<td>131.07 ms</td>
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<td>52.428 ms</td>
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<td>49.151 ms</td>
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<td>123.6 ms</td>
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<td>53.08 ms</td>
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</tr>
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<tr>
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<td align="center" bgcolor="#CFCFCF">Related Commands</td>
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<td align="center" colspan="7">
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<p colspan="7" align="center"><a href="PULSOUT.htm" target="" title="" alt="" class="MCXref_0">PULSOUT</a>, <a href="COUNT.htm" target="" title="" alt="" class="MCXref_0">COUNT</a></p>
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</td>
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</tr>
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</table>
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<h2>Explanation</h2>
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<p class="PlainText"><span class="keyword_in_text">PULSIN</span> is like a fast stopwatch that is triggered by a change in state
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(0 or 1) on the specified pin. The entire width of the specified pulse (high or
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low) is measured, in units shown above and stored in <i>Variable</i>. </p>
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<p class="PlainText">Many analog properties (voltage, resistance, capacitance, frequency, duty cycle)
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can be measured in terms of pulse duration. This makes <span class="keyword_in_text">PULSIN</span> a valuable
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form of analog-to-digital conversion. </p>
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<p class="PlainText"><span class="keyword_in_text">PULSIN</span> will wait for the desired pulse, for up to the maximum pulse
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width it can measure, shown in the table above. If it sees the desired pulse it
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measures the time until the end of the pulse and stores the result in <i>Variable</i>.
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If it never sees the start of the pulse, or the pulse is too long (greater than
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the Maximum Pulse Width shown above), <span class="keyword_in_text">PULSIN</span> "times out" and store 0 in
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<i>Variable</i>. This operation keeps your program from locking-up should the
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desired pulse never occur.</p>
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<p class="PlainText">Regardless of the size of <i>Variable</i>, <span class="keyword_in_text">PULSIN</span> internally uses a
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16-bit timer. Unless the pulse widths are known to be short enough to fit in an
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8-bit result, it is recommended using a word-sized variable. Not doing so may
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result in strange and misleading results as the BASIC Stamp will only store the
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lower 8-bits into a byte variable. </p>
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<div class="Col2">
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<div class="MasterFoot">
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<p MadCap:conditions="BSEconditions.BSEWebHelp (Primary)-INCLUDE"><a href="../../HomeTopics/HomePage.htm">Go to Welcome page</a>
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</p>
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</div>
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</div>
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<div class="Col2">
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<div class="MasterFoot">
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<p style="text-align: right;"><span class="ContactInfoProjectName">BASIC Stamp Help</span> <![CDATA[ ]]><span class="ContactInfoVersion#">Version 2.5.4</span> <![CDATA[ ]]></p>
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<p style="text-align: right;">Copyright © <span class="ContactInfoCompanyName">Parallax Inc.</span></p>
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<p style="text-align: right;"><span class="SystemShortDate">8/8/2012</span>
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</p>
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</div>
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