Branch: master
Find file Copy path
d00a014 Jun 4, 2014
1 contributor

Users who have contributed to this file

55 lines (43 sloc) 1.36 KB
#include <TimerOne.h>
// This example uses the timer interrupt to blink an LED
// and also demonstrates how to share a variable between
// the interrupt and the main program.
const int led = LED_BUILTIN; // the pin with a LED
void setup(void)
pinMode(led, OUTPUT);
Timer1.attachInterrupt(blinkLED); // blinkLED to run every 0.15 seconds
// The interrupt will blink the LED, and keep
// track of how many times it has blinked.
int ledState = LOW;
volatile unsigned long blinkCount = 0; // use volatile for shared variables
void blinkLED(void)
if (ledState == LOW) {
ledState = HIGH;
blinkCount = blinkCount + 1; // increase when LED turns on
} else {
ledState = LOW;
digitalWrite(led, ledState);
// The main program will print the blink count
// to the Arduino Serial Monitor
void loop(void)
unsigned long blinkCopy; // holds a copy of the blinkCount
// to read a variable which the interrupt code writes, we
// must temporarily disable interrupts, to be sure it will
// not change while we are reading. To minimize the time
// with interrupts off, just quickly make a copy, and then
// use the copy while allowing the interrupt to keep working.
blinkCopy = blinkCount;
Serial.print("blinkCount = ");