mirror of
https://github.com/arduino/Arduino.git
synced 2024-11-29 10:24:12 +01:00
53 lines
1.3 KiB
C++
53 lines
1.3 KiB
C++
/*
|
|
Input Pullup Serial
|
|
|
|
This example demonstrates the use of pinMode(INPUT_PULLUP). It reads a
|
|
digital input on pin 2 and prints the results to the serial monitor.
|
|
|
|
The circuit:
|
|
* Momentary switch attached from pin 2 to ground
|
|
* Built-in LED on pin 13
|
|
|
|
Unlike pinMode(INPUT), there is no pull-down resistor necessary. An internal
|
|
20K-ohm resistor is pulled to 5V. This configuration causes the input to
|
|
read HIGH when the switch is open, and LOW when it is closed.
|
|
|
|
created 14 March 2012
|
|
by Scott Fitzgerald
|
|
|
|
http://www.arduino.cc/en/Tutorial/InputPullupSerial
|
|
|
|
This example code is in the public domain
|
|
|
|
*/
|
|
|
|
void setup(){
|
|
//start serial connection
|
|
Serial.begin(9600);
|
|
//configure pin2 as an input and enable the internal pull-up resistor
|
|
pinMode(2, INPUT_PULLUP);
|
|
pinMode(13, OUTPUT);
|
|
|
|
}
|
|
|
|
void loop(){
|
|
//read the pushbutton value into a variable
|
|
int sensorVal = digitalRead(2);
|
|
//print out the value of the pushbutton
|
|
Serial.println(sensorVal);
|
|
|
|
// Keep in mind the pullup means the pushbutton's
|
|
// logic is inverted. It goes HIGH when it's open,
|
|
// and LOW when it's pressed. Turn on pin 13 when the
|
|
// button's pressed, and off when it's not:
|
|
if (sensorVal == HIGH) {
|
|
digitalWrite(13, LOW);
|
|
}
|
|
else {
|
|
digitalWrite(13, HIGH);
|
|
}
|
|
}
|
|
|
|
|
|
|