You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
111 lines
4.8 KiB
HTML
111 lines
4.8 KiB
HTML
15 years ago
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
||
|
|
<html>
|
||
|
|
<head>
|
||
|
|
<title>Arduino - DigitalRead </title>
|
||
|
|
<link rel='stylesheet' href='arduino.css' type='text/css' />
|
||
|
|
<meta name="verify-v1" content="TtxFIEJAB6zdJ509wLxjnapQzKAMNm9u0Wj4ho6wxIY=" />
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
<div id="page">
|
||
|
|
<!--PageHeaderFmt-->
|
||
|
|
<div id="pageheader">
|
||
|
|
<div class="title"><a href="http://www.arduino.cc"/>Arduino</a></div>
|
||
|
|
<div class="search">
|
||
|
|
<!-- SiteSearch Google -->
<FORM method=GET action="http://www.google.com/search">
<input type=hidden name=ie value=UTF-8>
<input type=hidden name=oe value=UTF-8>
<INPUT TYPE=text name=q size=25 maxlength=255 value="">
<INPUT type=submit name=btnG VALUE="search">
<input type=hidden name=domains value="http://www.arduino.cc/">
|
||
|
|
<input type=hidden name=sitesearch value="http://www.arduino.cc/">
|
||
|
|
</FORM>
<!-- SiteSearch Google -->
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
<!--/PageHeaderFmt-->
|
||
|
|
<!--PageLeftFmt-->
|
||
|
|
<div id="pagenav" style="text-align: right">
|
||
|
|
<div style="float: left;">
|
||
|
|
<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>
|
||
|
|
<a class="urllink" href="http://www.arduino.cc/blog/" rel="nofollow">Blog »</a> |
|
||
|
|
<a class="urllink" href="http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl" rel="nofollow">Forum »</a> |
|
||
|
|
<a class="urllink" href="http://www.arduino.cc/playground/" rel="nofollow">Playground »</a>
|
||
|
|
</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='Extended.html'>extended</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><h2>digitalRead()</h2>
|
||
|
|
<h4>Description</h4>
|
||
|
|
<p>Reads the value from a specified digital pin, either <a class='wikilink' href='Constants.html'>HIGH</a> or <a class='wikilink' href='Constants.html'>LOW</a>.
|
||
|
|
</p>
|
||
|
|
<p class='vspace'></p><h4>Syntax</h4>
|
||
|
|
<p>digitalRead(pin)
|
||
|
|
</p>
|
||
|
|
<p class='vspace'></p><h4>Parameters</h4>
|
||
|
|
<p>pin: the number of the digital pin you want to read (<em>int</em>)
|
||
|
|
</p>
|
||
|
|
<p class='vspace'></p><h4>Returns</h4>
|
||
|
|
<p><a class='wikilink' href='Constants.html'>HIGH</a> or <a class='wikilink' href='Constants.html'>LOW</a>
|
||
|
|
</p>
|
||
|
|
<p class='vspace'></p><h4>Example</h4>
|
||
|
|
<pre>
|
||
|
|
int ledPin = 13; // LED connected to digital pin 13
|
||
|
|
int inPin = 7; // pushbutton connected to digital pin 7
|
||
|
|
int val = 0; // variable to store the read value
|
||
|
|
|
||
|
|
void setup()
|
||
|
|
{
|
||
|
|
pinMode(ledPin, OUTPUT); // sets the digital pin 13 as output
|
||
|
|
pinMode(inPin, INPUT); // sets the digital pin 7 as input
|
||
|
|
}
|
||
|
|
|
||
|
|
void loop()
|
||
|
|
{
|
||
|
|
val = digitalRead(inPin); // read the input pin
|
||
|
|
digitalWrite(ledPin, val); // sets the LED to the button's value
|
||
|
|
}
|
||
|
|
|
||
|
|
</pre>
|
||
|
|
<p class='vspace'></p><p>Sets pin 13 to the same value as the pin 7, which is an input.
|
||
|
|
</p>
|
||
|
|
<p class='vspace'></p><h4>Note</h4>
|
||
|
|
<p>If the pin isn't connected to anything, digitalRead() can return either HIGH or LOW (and this can change randomly).
|
||
|
|
</p>
|
||
|
|
<p class='vspace'></p><p>The analog input pins can be used as digital pins w/ numbers 14 (analog input 0) to 19 (analog input 5).
|
||
|
|
</p>
|
||
|
|
<p class='vspace'></p><h4>See also</h4>
|
||
|
|
<ul><li><a class='wikilink' href='PinMode.html'>pinMode</a>()
|
||
|
|
</li><li><a class='wikilink' href='DigitalWrite.html'>digitalWrite</a>()
|
||
|
|
</li><li><a class='wikilink' href='http://arduino.cc/en/Tutorial/DigitalPins'>Tutorial: Digital Pins</a>
|
||
|
|
</li></ul><p class='vspace'></p><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://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?board=swbugs' 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>. Code samples in the reference are released into the public domain.
|
||
|
|
</p>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
</div>
|
||
|
|
<!--PageFooterFmt-->
|
||
|
|
<div id="pagefooter">
|
||
|
|
<a href='#'>Edit Page</a> | <a href='#'>Page History</a> | <a href='#' target='_blank'>Printable View</a> | <a href='http://arduino.cc/en/Site/AllRecentChanges'>All Recent Site Changes</a>
|
||
|
|
</div>
|
||
|
|
<!--/PageFooterFmt-->
|
||
|
|
</div>
|
||
|
|
</body>
|
||
|
|
</html>
|