4

This is my code which I have written as a library

#include "avr/interrupt.h"  
#include "Arduino.h"
#include "AllTimer.h"

AllTimer::AllTimer()
{}

void AllTimer::dofun(void)
{
     //TIFR1 |= _BV(OCF1A);

    TCCR1B = 0X00;
    //TIFR1 = 0X01;
    digitalWrite(13,!digitalRead(13));
    Serial.print("I printed");
    TCNT1 = 0X0000;
    TCCR1B |= (1<<CS12) && (1<<CS10);
    //sei();
}

 void AllTimer::setTimer(void)
 {
    TCNT1 = 0x0000;
    TCCR1A = 0x00;
    TCCR1B = 0x00;
    TCCR1B |= (1<<CS12) && (1<<CS10);
    TIMSK1 |= (1<<TOIE1);
    sei();
 }

ISR (TIMER1_OVF_vect)
{
     AllTimer::dofun();
}  

Code in Arduino IDE:

 #include <AllTimer.h>

 AllTimer mytimer;

 void setup()
 {
     pinMode(13,OUTPUT);
     Serial.begin(9600);
 }

 void loop()
 {  
     mytimer.setTimer();
    //delay(200);   
  }

But I am not getting anything on the serial monitor. What is the error I have made?

  • 2
    Using Serial.print inside an ISR is asking for problems. Does the led blink? Also, there is no need to write TCCR1B and TCNT1 inside doFun. – Gerben Mar 16 '15 at 14:12
7

The Arduino main() calls loop() continuously, in a tight loop. Thus your AllTimer::setTimer() is called continuously, and each time it resets the counter (TCNT1 = 0x0000;). Thus the counter can never overflow.

  • 2
    So put mytimer.setTimer(); inside setup instead of loop. – Gerben Mar 16 '15 at 14:12
  • also, in TCCR1B |= (1<<CS12) && (1<<CS10); shouldn't it be | instead of the logic &&? – Sim Son Apr 6 at 21:04
  • @SimSon: Indeed! I hadn't spotted that. Good catch. – Edgar Bonet Apr 7 at 9:02

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