SimpleTimer

SimpleTimer.cpp

/*
 * SimpleTimer.cpp
 *
 * SimpleTimer - A timer library for Arduino.
 * Author: [email protected]
 * Copyright (c) 2010 OTTOTECNICA Italy
 *
 * This library is free software; you can redistribute it
 * and/or modify it under the terms of the GNU Lesser
 * General Public License as published by the Free Software
 * Foundation; either version 2.1 of the License, or (at
 * your option) any later version.
 *
 * This library is distributed in the hope that it will
 * be useful, but WITHOUT ANY WARRANTY; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser
 * General Public License along with this library; if not,
 * write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */


#include "SimpleTimer.h"


// Select time function:
//static inline unsigned long elapsed() { return micros(); }
static inline unsigned long elapsed() { return millis(); }


SimpleTimer::SimpleTimer() {
    unsigned long current_millis = elapsed();

    for (int i = 0; i < MAX_TIMERS; i++) {
        enabled[i] = false;
        callbacks[i] = 0;                   // if the callback pointer is zero, the slot is free, i.e. doesn't "contain" any timer
        prev_millis[i] = current_millis;
        numRuns[i] = 0;
    }

    numTimers = 0;
}


void SimpleTimer::run() {
    int i;
    unsigned long current_millis;

    // get current time
    current_millis = elapsed();

    for (i = 0; i < MAX_TIMERS; i++) {

        toBeCalled[i] = DEFCALL_DONTRUN;

        // no callback == no timer, i.e. jump over empty slots
        if (callbacks[i]) {

            // is it time to process this timer ?
            // see http://arduino.cc/forum/index.php/topic,124048.msg932592.html#msg932592

            if (current_millis - prev_millis[i] >= delays[i]) {

                // update time
                //prev_millis[i] = current_millis;
                prev_millis[i] += delays[i];

                // check if the timer callback has to be executed
                if (enabled[i]) {

                    // "run forever" timers must always be executed
                    if (maxNumRuns[i] == RUN_FOREVER) {
                        toBeCalled[i] = DEFCALL_RUNONLY;
                    }
                    // other timers get executed the specified number of times
                    else if (numRuns[i] < maxNumRuns[i]) {
                        toBeCalled[i] = DEFCALL_RUNONLY;
                        numRuns[i]++;

                        // after the last run, delete the timer
                        if (numRuns[i] >= maxNumRuns[i]) {
                            toBeCalled[i] = DEFCALL_RUNANDDEL;
                        }
                    }
                }
            }
        }
    }

    for (i = 0; i < MAX_TIMERS; i++) {
        switch(toBeCalled[i]) {
            case DEFCALL_DONTRUN:
                break;

            case DEFCALL_RUNONLY:
                (*callbacks[i])();
                break;

            case DEFCALL_RUNANDDEL:
                (*callbacks[i])();
                deleteTimer(i);
                break;
        }
    }
}


// find the first available slot
// return -1 if none found
int SimpleTimer::findFirstFreeSlot() {
    int i;

    // all slots are used
    if (numTimers >= MAX_TIMERS) {
        return -1;
    }

    // return the first slot with no callback (i.e. free)
    for (i = 0; i < MAX_TIMERS; i++) {
        if (callbacks[i] == 0) {
            return i;
        }
    }

    // no free slots found
    return -1;
}


int SimpleTimer::setTimer(long d, timer_callback f, int n) {
    int freeTimer;

    freeTimer = findFirstFreeSlot();
    if (freeTimer < 0) {
        return -1;
    }

    if (f == NULL) {
        return -1;
    }

    delays[freeTimer] = d;
    callbacks[freeTimer] = f;
    maxNumRuns[freeTimer] = n;
    enabled[freeTimer] = true;
    prev_millis[freeTimer] = elapsed();

    numTimers++;

    return freeTimer;
}


int SimpleTimer::setInterval(long d, timer_callback f) {
    return setTimer(d, f, RUN_FOREVER);
}


int SimpleTimer::setTimeout(long d, timer_callback f) {
    return setTimer(d, f, RUN_ONCE);
}


void SimpleTimer::deleteTimer(int timerId) {
    if (timerId >= MAX_TIMERS) {
        return;
    }

    // nothing to delete if no timers are in use
    if (numTimers == 0) {
        return;
    }

    // don't decrease the number of timers if the
    // specified slot is already empty
    if (callbacks[timerId] != NULL) {
        callbacks[timerId] = 0;
        enabled[timerId] = false;
        delays[timerId] = 0;
        numRuns[timerId] = 0;

        // update number of timers
        numTimers--;
    }
}


// function contributed by [email protected]
void SimpleTimer::restartTimer(int numTimer) {
    if (numTimer >= MAX_TIMERS) {
        return;
    }

    prev_millis[numTimer] = elapsed();
}


boolean SimpleTimer::isEnabled(int numTimer) {
    if (numTimer >= MAX_TIMERS) {
        return false;
    }

    return enabled[numTimer];
}


void SimpleTimer::enable(int numTimer) {
    if (numTimer >= MAX_TIMERS) {
        return;
    }

    enabled[numTimer] = true;
}


void SimpleTimer::disable(int numTimer) {
    if (numTimer >= MAX_TIMERS) {
        return;
    }

    enabled[numTimer] = false;
}


void SimpleTimer::toggle(int numTimer) {
    if (numTimer >= MAX_TIMERS) {
        return;
    }

    enabled[numTimer] = !enabled[numTimer];
}


int SimpleTimer::getNumTimers() {
    return numTimers;
}

SimpleTimer.h

/*
 * SimpleTimer.h
 *
 * SimpleTimer - A timer library for Arduino.
 * Author: [email protected]
 * Copyright (c) 2010 OTTOTECNICA Italy
 *
 * This library is free software; you can redistribute it
 * and/or modify it under the terms of the GNU Lesser
 * General Public License as published by the Free Software
 * Foundation; either version 2.1 of the License, or (at
 * your option) any later version.
 *
 * This library is distributed in the hope that it will
 * be useful, but WITHOUT ANY WARRANTY; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser
 * General Public License along with this library; if not,
 * write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 *
 */


#ifndef SIMPLETIMER_H
#define SIMPLETIMER_H

#if defined(ARDUINO) && ARDUINO >= 100
#include <Arduino.h>
#else
#include <WProgram.h>
#endif

typedef void (*timer_callback)(void);

class SimpleTimer {

public:
    // maximum number of timers
    const static int MAX_TIMERS = 10;

    // setTimer() constants
    const static int RUN_FOREVER = 0;
    const static int RUN_ONCE = 1;

    // constructor
    SimpleTimer();

    // this function must be called inside loop()
    void run();

    // call function f every d milliseconds
    int setInterval(long d, timer_callback f);

    // call function f once after d milliseconds
    int setTimeout(long d, timer_callback f);

    // call function f every d milliseconds for n times
    int setTimer(long d, timer_callback f, int n);

    // destroy the specified timer
    void deleteTimer(int numTimer);

    // restart the specified timer
    void restartTimer(int numTimer);

    // returns true if the specified timer is enabled
    boolean isEnabled(int numTimer);

    // enables the specified timer
    void enable(int numTimer);

    // disables the specified timer
    void disable(int numTimer);

    // enables the specified timer if it's currently disabled,
    // and vice-versa
    void toggle(int numTimer);

    // returns the number of used timers
    int getNumTimers();

    // returns the number of available timers
    int getNumAvailableTimers() { return MAX_TIMERS - numTimers; };

private:
    // deferred call constants
    const static int DEFCALL_DONTRUN = 0;       // don't call the callback function
    const static int DEFCALL_RUNONLY = 1;       // call the callback function but don't delete the timer
    const static int DEFCALL_RUNANDDEL = 2;      // call the callback function and delete the timer

    // find the first available slot
    int findFirstFreeSlot();

    // value returned by the millis() function
    // in the previous run() call
    unsigned long prev_millis[MAX_TIMERS];

    // pointers to the callback functions
    timer_callback callbacks[MAX_TIMERS];

    // delay values
    long delays[MAX_TIMERS];

    // number of runs to be executed for each timer
    int maxNumRuns[MAX_TIMERS];

    // number of executed runs for each timer
    int numRuns[MAX_TIMERS];

    // which timers are enabled
    boolean enabled[MAX_TIMERS];

    // deferred function call (sort of) - N.B.: this array is only used in run()
    int toBeCalled[MAX_TIMERS];

    // actual number of timers in use
    int numTimers;
};

#endif

SimpleTimerAlarmExample.ino

/*
 * SimpleTimerAlarmExample.ino
 *
 * Based on usage example for Time + TimeAlarm libraries
 *
 * A timer is called every 15 seconds
 * Another timer is called once only after 10 seconds
 * A third timer is called 10 times.
 *
 */

#include <SimpleTimer.h>

// There must be one global SimpleTimer object.
// More SimpleTimer objects can be created and run,
// although there is little point in doing so.
SimpleTimer timer;

// function to be called repeatedly
void RepeatTask() {
  Serial.println("15 second timer");        
}

// function to be called just once
void OnceOnlyTask() {
  Serial.println("This timer only triggers once");  
}

// function to be called exactly 10 times
void TenTimesTask() {
  static int k = 0;
  k++;
  Serial.print("called ");
  Serial.print(k);
  Serial.println(" / 10 times.");
}

// print current arduino "uptime" on the serial port
void DigitalClockDisplay() {
  int h,m,s;
  s = millis() / 1000;
  m = s / 60;
  h = s / 3600;
  s = s - m * 60;
  m = m - h * 60;
  Serial.print(h);
  printDigits(m);
  printDigits(s);
  Serial.println();
}

//
// utility function for digital clock display:
// prints preceding colon and leading 0
//
void printDigits(int digits) {
  Serial.print(":");
  if(digits < 10)
    Serial.print('0');
  Serial.print(digits);
}

void setup() {
  Serial.begin(9600);

  // welcome message
  Serial.println("SimpleTimer Example");
  Serial.println("One timer is triggered every 15 seconds");
  Serial.println("Another timer is set to trigger only once after 10 seconds");
  Serial.println("Another timer is set to trigger 10 times");
  Serial.println();

  // timed actions setup
  timer.setInterval(15000, RepeatTask);
  timer.setTimeout(10000, OnceOnlyTask);
  timer.setInterval(1000, DigitalClockDisplay);
  timer.setTimer(1200, TenTimesTask, 10);
}

void loop() {
  // this is where the "polling" occurs
  timer.run();
}