<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html> <head> <title>Arduino Reference - WireRead </title> <link rel="shortcut icon" type="image/x-icon" href="http://arduino.cc/en/favicon.png"> <link rel='stylesheet' href='arduinoWideRender.css' type='text/css' /> <!--HeaderText--><style type='text/css'><!-- ul, ol, pre, dl, p { margin-top:0px; margin-bottom:0px; } code { white-space: nowrap; } .vspace { margin-top:1.33em; } .indent { margin-left:40px; } .outdent { margin-left:40px; text-indent:-40px; } a.createlinktext { text-decoration:none; border-bottom:1px dotted gray; } a.createlink { text-decoration:none; position:relative; top:-0.5em; font-weight:bold; font-size:smaller; border-bottom:none; } img { border:0px; } .editconflict { color:green; font-style:italic; margin-top:1.33em; margin-bottom:1.33em; } table.markup { border: 2px dotted #ccf; width:90%; } td.markup1, td.markup2 { padding-left:10px; 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content='index,follow' /> <meta name="verify-v1" content="TtxFIEJAB6zdJ509wLxjnapQzKAMNm9u0Wj4ho6wxIY=" /> </head> <body> <div id="page"> <!--PageHeaderFmt--> <div id="pageheader"> <div class="title"><a href='http://arduino.cc/en'>Arduino</a></div> </div> <!--/PageHeaderFmt--> <!--PageLeftFmt--> <div id="pagenav"> <div id="navbar"> <p><a class='wikilink' href='http://arduino.cc/en/Main/Buy'>Buy</a> <a class='wikilink' href='http://arduino.cc/en/Main/Software'>Download</a> <a class='wikilink' href='Guide_index.html'>Getting Started</a> <a class='wikilink' href='http://arduino.cc/en/Tutorial/HomePage'>Learning</a> <a class='wikilink' href='index.html'>Reference</a> <a class='wikilink' href='http://arduino.cc/en/Main/Hardware'>Hardware</a> <a class='wikilink' href='FAQ.html'>FAQ</a> </p> <p class='vspace'></p> </div> </div> <!--/PageLeftFmt--> <div id="pagetext"> <!--PageText--> <div id='wikitext'> <p><strong>Reference</strong> <a class='wikilink' href='index.html'>Language</a> | <a class='wikilink' href='Libraries.html'>Libraries</a> | <a class='wikilink' href='Comparison.html'>Comparison</a> | <a class='wikilink' href='Changes.html'>Changes</a> </p> <p class='vspace'></p><p><a class='wikilink' href='Wire.html'>Wire</a> </p> <p class='vspace'></p><h2>read()</h2> <h4>Description</h4> <p>Reads a byte that was transmitted from a slave device to a master after a call to <a class='wikilink' href='WireRequestFrom.html'>requestFrom()</a> or was transmitted from a master to a slave. read() inherits from the <a class='wikilink' href='Stream.html'>Stream</a> utility class. </p> <p class='vspace'></p><h4>Syntax</h4> <p>Wire.read() <br /> </p><h4>Parameters</h4> <p>none </p> <p class='vspace'></p><h4>Returns</h4> <p>The next byte received </p> <p class='vspace'></p><h4>Example</h4> <p> <div class='sourceblock ' id='sourceblock1'> <div class='sourceblocktext'><div class="arduino"><span class="co2">#include <Wire.h></span><br /> <br /> <span class="kw1">void</span> <span class="kw3">setup</span><span class="br0">(</span><span class="br0">)</span><br /> <span class="br0">{</span><br /> Wire.<span class="kw1">begin</span><span class="br0">(</span><span class="br0">)</span><span class="sy0">;</span> <span class="co1">// join i2c bus (address optional for master)</span><br /> <span class="kw1">Serial</span>.<span class="kw1">begin</span><span class="br0">(</span><span class="nu0">9600</span><span class="br0">)</span><span class="sy0">;</span> <span class="co1">// start serial for output</span><br /> <span class="br0">}</span><br /> <br /> <span class="kw1">void</span> <span class="kw3">loop</span><span class="br0">(</span><span class="br0">)</span><br /> <span class="br0">{</span><br /> Wire.<span class="kw1">requestFrom</span><span class="br0">(</span><span class="nu0">2</span><span class="sy0">,</span> <span class="nu0">6</span><span class="br0">)</span><span class="sy0">;</span> <span class="co1">// request 6 bytes from slave device #2</span><br /> <br /> <span class="kw1">while</span><span class="br0">(</span>Wire.<span class="kw1">available</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span> <span class="co1">// slave may send less than requested</span><br /> <span class="br0">{</span> <br /> <span class="kw1">char</span> c <span class="sy0">=</span> Wire.<span class="kw1">read</span><span class="br0">(</span><span class="br0">)</span><span class="sy0">;</span> <span class="co1">// receive a byte as character</span><br /> <span class="kw1">Serial</span>.<span class="kw1">print</span><span class="br0">(</span>c<span class="br0">)</span><span class="sy0">;</span> <span class="co1">// print the character</span><br /> <span class="br0">}</span><br /> <br /> <span class="kw1">delay</span><span class="br0">(</span><span class="nu0">500</span><span class="br0">)</span><span class="sy0">;</span><br /> <span class="br0">}</span></div></div> <div class='sourceblocklink'><a href='#' type='text/plain'>[Get Code]</a></div> </div> </p> <p class='vspace'></p><h4>See also</h4> <ul><li><a class='wikilink' href='WireWrite.html'>WireWrite</a>() </li><li><a class='wikilink' href='WireAvailable.html'>WireAvailable</a>() </li><li><a class='wikilink' href='WireRequestFrom.html'>WireRequestFrom</a>() </li><li><a class='wikilink' href='StreamRead.html'>Stream.read</a>() </li></ul><p><a class='wikilink' href='index.html'>Reference Home</a> </p> <p class='vspace'></p><p><em>Corrections, suggestions, and new documentation should be posted to the <a class='urllink' href='http://arduino.cc/forum/index.php/board,23.0.html' rel='nofollow'>Forum</a>.</em> </p> <p class='vspace'></p><p>The text of the Arduino reference is licensed under a <a class='urllink' href='http://creativecommons.org/licenses/by-sa/3.0/' rel='nofollow'>Creative Commons Attribution-ShareAlike 3.0 License</a>. 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