Simple Timer

Original Author: Andrew Mascolo (HazardsMind)

Modified By: Unknown, (Date?)

Modified By: Andrew Mascolo, 4/13/2016


This sketch is a simple way to execute functions at different time intervals.

class Timer
{
  private:
    unsigned long lastTime;  // the latest time had doing Func( )
    void (*Func) (void);
    void (*backupFunc) (void);  // backup Func for start( )
    unsigned long T_int;   // interval in ms, can be set as in us (optional)

  public:
    Timer(void (*userFunc)(), unsigned long T, bool isTinUs = false)
    {
      Func = backupFunc = userFunc;  // save the function pointer
      T_int = T * 1000;
      if (isTinUs)
        T_int = T;  // T is in micro second as per unit

      lastTime = 0;  // initialization should be in constructor
    }

    void check()
    {
      if ( Func == 0 )
        return; // no function pointer

      unsigned long _micros = micros(); // Local variable could be in Register

      if (_micros - lastTime >= T_int)
      {
        lastTime = _micros;  // latest time doing Func( )
        Func();
      }
    }// check

    void start( )   // first run of doing Func( )
    {
      if (Func == 0)
        Func = backupFunc; // restore after .stop( )

      lastTime = micros();  // latest time doing Func( )
      Func();   // First run
    } // start

    void stop( )   // stop the scheduled Func  (userFunc)
    {
      Func = 0;  // set as NULL
    } // stop

#define _MS_ false /*Milliseconds*/
#define _US_ true  /*Microseconds*/
};

Timer T1(Blink1, 88000, _US_); // 88000us (NOT ms)
Timer T2(Blink2, 1000);  // 1000ms
Timer T3(Blink3, 2000); // 2000ms

void setup()
{
  // put your setup code here, to run once:
  pinMode(13, OUTPUT);
  pinMode(11, OUTPUT);
  pinMode(9, OUTPUT);
  T1.start()    ; // optional to use the .start( ) function
  delay(2568); // On Purpose for you  to compare T1 vs. T2, T3
}

void loop()
{
  // put your main code here, to run repeatedly:
  T1.check();
  T2.check();
  T3.check();
}

void Blink1()
{
  digitalWrite(13, !digitalRead(13));
}

void Blink2()
{
  digitalWrite(9, !digitalRead(9));
}

void Blink3()
{
  digitalWrite(11, !digitalRead(11));
}

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