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<div class="title"><a href='http://arduino.cc/en'>Arduino</a></div>
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<p><a class='wikilink' href='Serial.html'>Serial</a>
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<p class='vspace'></p><h2>available()</h2>
<h4>Description</h4>
<p>Get the number of bytes (characters) available for reading from the serial port. This is data that's already arrived and stored in the serial receive buffer (which holds 128 bytes). available() inherits from the <a class='wikilink' href='Stream.html'>Stream</a> utility class.
</p>
<p class='vspace'></p><h4>Syntax</h4>
<p>Serial.available()
</p>
<p class='vspace'></p><p><em>Arduino Mega only:</em> <br />Serial1.available() <br />Serial2.available() <br />Serial3.available()
</p>
<p class='vspace'></p><h3>Parameters</h3>
<p>none
</p>
<p class='vspace'></p><h4>Returns</h4>
<p>the number of bytes available to read
</p>
<p class='vspace'></p><h3>Example</h3>
<p>
<div class='sourceblock ' id='sourceblock1'>
<div class='sourceblocktext'><div class="arduino"><span class="kw1">int</span> incomingByte <span class="sy0">=</span> <span class="nu0">0</span><span class="sy0">;</span> <span class="co1">// for incoming serial data</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="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">// opens serial port, sets data rate to 9600 bps</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 />
<br />
<span class="co1">// send data only when you receive data:</span><br />
<span class="kw1">if</span> <span class="br0">(</span><span class="kw1">Serial</span>.<span class="kw1">available</span><span class="br0">(</span><span class="br0">)</span> <span class="sy0">></span> <span class="nu0">0</span><span class="br0">)</span> <span class="br0">{</span><br />
<span class="co1">// read the incoming byte:</span><br />
incomingByte <span class="sy0">=</span> <span class="kw1">Serial</span>.<span class="kw1">read</span><span class="br0">(</span><span class="br0">)</span><span class="sy0">;</span><br />
<br />
<span class="co1">// say what you got:</span><br />
<span class="kw1">Serial</span>.<span class="kw1">print</span><span class="br0">(</span><span class="st0">"I received: "</span><span class="br0">)</span><span class="sy0">;</span><br />
<span class="kw1">Serial</span>.<span class="kw1">println</span><span class="br0">(</span>incomingByte<span class="sy0">,</span> <span class="kw2">DEC</span><span class="br0">)</span><span class="sy0">;</span><br />
<span class="br0">}</span><br />
<span class="br0">}</span><br />
@<span class="br0">]</span><br />
<br />
<span class="st0">''</span><span class="st0">'Arduino Mega example:'</span><span class="st0">''</span><br />
<br />
<span class="br0">[</span>@<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="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="kw1">Serial1</span>.<span class="kw1">begin</span><span class="br0">(</span><span class="nu0">9600</span><span class="br0">)</span><span class="sy0">;</span><br />
<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">// read from port 0, send to port 1:</span><br />
<span class="kw1">if</span> <span class="br0">(</span><span class="kw1">Serial</span>.<span class="kw1">available</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span><br />
<span class="kw1">int</span> inByte <span class="sy0">=</span> <span class="kw1">Serial</span>.<span class="kw1">read</span><span class="br0">(</span><span class="br0">)</span><span class="sy0">;</span><br />
<span class="kw1">Serial1</span>.<span class="kw1">print</span><span class="br0">(</span>inByte<span class="sy0">,</span> <span class="kw2">BYTE</span><span class="br0">)</span><span class="sy0">;</span> <br />
<br />
<span class="br0">}</span><br />
<span class="co1">// read from port 1, send to port 0:</span><br />
<span class="kw1">if</span> <span class="br0">(</span><span class="kw1">Serial1</span>.<span class="kw1">available</span><span class="br0">(</span><span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span><br />
<span class="kw1">int</span> inByte <span class="sy0">=</span> <span class="kw1">Serial1</span>.<span class="kw1">read</span><span class="br0">(</span><span class="br0">)</span><span class="sy0">;</span><br />
<span class="kw1">Serial</span>.<span class="kw1">print</span><span class="br0">(</span>inByte<span class="sy0">,</span> <span class="kw2">BYTE</span><span class="br0">)</span><span class="sy0">;</span> <br />
<span class="br0">}</span><br />
<span class="br0">}</span></div></div>
<div class='sourceblocklink'><a href='Serial_Available?action=sourceblock&num=1.html' type='text/plain'>[Get Code]</a></div>
</div>
</p>
<p class='vspace'></p><h4>See also</h4>
<ul><li><a class='wikilink' href='Serial_Read.html'>Serial.read</a>()
</li><li><a class='wikilink' href='Serial_Flush.html'>Serial.flush</a>()
</li><li><a class='wikilink' href='StreamAvailable.html'>Stream.available</a>()
</li></ul><p class='vspace'></p><p><a class='wikilink' href='index.html'>Reference Home</a>
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