66 lines
3.2 KiB
C++
66 lines
3.2 KiB
C++
// PinChangeInt SimpleExample sketch
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// See the Wiki at http://code.google.com/p/arduino-pinchangeint/wiki for more information.
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// for vim editing: :set et ts=2 sts=2 sw=2 et
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// This example demonstrates the use of the PinChangeInt library on a single pin of your choice.
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// This only works for ATMega328-compatibles; ie, Leonardo is not covered here.
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// To use:
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// 1. You must be using a fairly recent version of the Arduino IDE software on your PC/Mac,
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// that is, version 1.0.1 or later. Check Help->About Arduino in the IDE.
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// 2. Wire a simple switch to any Analog or Digital pin (known as ARDUINOPIN, defined below).
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// Attach the other end to a GND pin. A "single pole single throw momentary contact"
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// pushbutton switch is best for the best interrupting fun.
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// 3. When pressed, the switch will connect the pin to ground ("low", or "0") voltage, and interrupt the
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// processor. Don't let it confuse you that a switch press means the pin's voltage goes to 0; it
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// may seem more intuitive to apply a "1" or high voltage to the pin to represent "pressed".
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// But the processor is perfectly happy that we've made "0" equal "Pressed". The reason we've done so
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// is because we are using the "internal pullup resistor" feature of the processor... the chip gives
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// us a free resistor on every pin!
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// See http://arduino.cc/en/Tutorial/DigitalPins for a complete explanation.
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// 4. The interrupt is serviced immediately, and the ISR (Interrupt SubRoutine) sets the value of a global
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// variable. The sketch can then query the value at its leisure. This makes loop timing non-critical.
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// Open Tools->Serial Monitor in the IDE to see the results of your interrupts.
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// 5. See PinChangeIntExample328.ino (in the PinChangeInt distribution) for a more elaborate example.
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// 6. Create your own sketch using the PinChangeInt library!
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#include <PinChangeInt.h>
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// Modify this at your leisure.
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#define ARDUINOPIN A4
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// Notice that values that get modified inside an interrupt, that I wish to access
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// outside the interrupt, are marked "volatile". It tells the compiler not to optimize
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// the variable.
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volatile uint16_t interruptCount=0; // The count will go back to 0 after hitting 65535.
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// Do not use any Serial.print() in interrupt subroutines. Serial.print() uses interrupts,
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// and by default interrupts are off in interrupt subroutines. Interrupt routines should also
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// be as fast as possible. Here we just increment a counter.
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void interruptFunction() {
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interruptCount++;
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}
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// Attach the interrupt in setup()
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void setup() {
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pinMode(ARDUINOPIN, INPUT_PULLUP); // Configure the pin as an input, and turn on the pullup resistor.
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// See http://arduino.cc/en/Tutorial/DigitalPins
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attachPinChangeInterrupt(ARDUINOPIN, interruptFunction, FALLING);
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Serial.begin(115200);
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Serial.println("---------------------------------------");
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}
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// In the loop, we just check to see where the interrupt count is at. The value gets updated by the
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// interrupt routine.
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void loop() {
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delay(1000); // Every second,
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Serial.print("Pin was interrupted: ");
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Serial.print(interruptCount, DEC); // print the interrupt count.
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Serial.println(" times so far.");
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}
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