<!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 - EthernetUDPParsePacket </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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<br /> </p><h4>Parameters</h4> <p>None </p> <p class='vspace'></p><h4>Returns</h4> <p>int: the size of a received UDP packet </p> <p class='vspace'></p><h4>Example</h4> <p> <div class='sourceblock ' id='sourceblock1'> <div class='sourceblocktext'><div class="arduino"><br /> <span class="co2">#include <SPI.h> // needed for Arduino versions later than 0018</span><br /> <span class="co2">#include <Ethernet.h></span><br /> <span class="co2">#include <EthernetUdp.h> // UDP library from: bjoern@cs.stanford.edu 12/30/2008</span><br /> <br /> <br /> <span class="co1">// Enter a MAC address and IP address for your controller below.</span><br /> <span class="co1">// The IP address will be dependent on your local network:</span><br /> <span class="kw1">byte</span> mac<span class="br0">[</span><span class="br0">]</span> <span class="sy0">=</span> <span class="br0">{</span> <br /> <span class="nu12">0xDE</span><span class="sy0">,</span> <span class="nu12">0xAD</span><span class="sy0">,</span> <span class="nu12">0xBE</span><span class="sy0">,</span> <span class="nu12">0xEF</span><span class="sy0">,</span> <span class="nu12">0xFE</span><span class="sy0">,</span> <span class="nu12">0xED</span> <span class="br0">}</span><span class="sy0">;</span><br /> IPAddress ip<span class="br0">(</span><span class="nu0">192</span><span class="sy0">,</span> <span class="nu0">168</span><span class="sy0">,</span> <span class="nu0">1</span><span class="sy0">,</span> <span class="nu0">177</span><span class="br0">)</span><span class="sy0">;</span><br /> <br /> <span class="kw1">unsigned</span> <span class="kw1">int</span> localPort <span class="sy0">=</span> <span class="nu0">8888</span><span class="sy0">;</span> <span class="co1">// local port to listen on</span><br /> <br /> <span class="co1">// An EthernetUDP instance to let us send and receive packets over UDP</span><br /> EthernetUDP Udp<span class="sy0">;</span><br /> <br /> <span class="kw1">void</span> <span class="kw3">setup</span><span class="br0">(</span><span class="br0">)</span> <span class="br0">{</span><br /> <span class="co1">// start the Ethernet and UDP:</span><br /> Ethernet.<span class="kw1">begin</span><span class="br0">(</span>mac<span class="sy0">,</span>ip<span class="br0">)</span><span class="sy0">;</span><br /> Udp.<span class="kw1">begin</span><span class="br0">(</span>localPort<span class="br0">)</span><span class="sy0">;</span><br /> <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><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> <span class="br0">{</span><br /> <span class="co1">// if there's data available, read a packet</span><br /> <span class="kw1">int</span> packetSize <span class="sy0">=</span> Udp.<span class="me1">parsePacket</span><span class="br0">(</span><span class="br0">)</span><span class="sy0">;</span><br /> <span class="kw1">if</span><span class="br0">(</span>packetSize<span class="br0">)</span><br /> <span class="br0">{</span><br /> <span class="kw1">Serial</span>.<span class="kw1">print</span><span class="br0">(</span><span class="st0">"Received packet of size "</span><span class="br0">)</span><span class="sy0">;</span><br /> <span class="kw1">Serial</span>.<span class="kw1">println</span><span class="br0">(</span>packetSize<span class="br0">)</span><span class="sy0">;</span><br /> <span class="br0">}</span><br /> <span class="kw1">delay</span><span class="br0">(</span><span class="nu0">10</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='EthernetUDPRead.html'>UDP.read()</a><br /> </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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