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126 lines
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126 lines
4.7 KiB
HTML
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<title>Arduino Reference - BooleanVariables </title>
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<div class="title"><a href='http://arduino.cc/en'>Arduino</a></div>
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<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>
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</p>
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<p class='vspace'></p><h2>boolean</h2>
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<p>A <strong>boolean</strong> holds one of two values, <a class='wikilink' href='Constants.html'>true</a> or <a class='wikilink' href='Constants.html'>false</a>. (Each boolean variable occupies one byte of memory.)
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</p>
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<p class='vspace'></p><h4>Example</h4>
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<pre>
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int LEDpin = 5; // LED on pin 5
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int switchPin = 13; // momentary switch on 13, other side connected to ground
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boolean running = false;
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void setup()
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{
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pinMode(LEDpin, OUTPUT);
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pinMode(switchPin, INPUT);
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digitalWrite(switchPin, HIGH); // turn on pullup resistor
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}
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void loop()
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{
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if (digitalRead(switchPin) == LOW)
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{ // switch is pressed - pullup keeps pin high normally
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delay(100); // delay to debounce switch
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running = !running; // toggle running variable
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digitalWrite(LEDpin, running) // indicate via LED
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}
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}
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</pre>
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<p class='vspace'></p><h4>See also</h4>
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<ul><li><a class='wikilink' href='Constants.html'>constants</a>
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</li><li><a class='wikilink' href='Boolean.html'>boolean operators</a>
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</li><li><a class='urllink' href='http://arduino.cc/en/Reference/VariableDeclaration' rel='nofollow'>Variable Declaration</a>
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</li></ul><p><a class='wikilink' href='index.html'>Reference Home</a>
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<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>
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</p>
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<p class='vspace'></p><p>The text of the Arduino reference is licensed under a
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<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.
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