Condition after interrupt only meet, if previously printed

Using Arduino Programming Questions
1

Hello Guys,

I made a mistake I can’t understand. It’s a bit like quantum physics. If you watch, it is were you think it is. If not, it’s everywhere.

I’m counting up a int „i_timer“ every time a timer interrupt is triggered. My main program is waiting in a while till i_timer is bigger then 0.

The problem:
The “if” condition inside the while only is meet if i_timer is printed in every circle of the while.
When i_timer is not printed, the condition is never meet.
I tried different delays instead of the print, to make sure is not related to the time spent printing.
The serial.print Funktion somehow must erases some mistake I made. Maybe someone knows what it could be, so I can find my mistake.

2

Here you can see the vital Funktion for the Problem.


void Output_End()
{
  Next_OCR=30000;
  i_timer=0;
  while(1)
  {
    //Serial.println(i_timer); //why
    //delay(0.1);

    if(i_timer>0)
    {
      noInterrupts();
      TIMSK1 |= (1 << OCIE1A);
      toggle = false; 
      digitalWrite(OUTPUT_PIN, toggle); 
      return; 
    }
    else
    {
      delay(0.1);
    }

  }
}

ISR(TIMER1_COMPA_vect)          // timer compare interrupt service routine
{
  noInterrupts();
  OCR1A=Next_OCR;
  i_timer++; 
  toggle = !toggle; 
  digitalWrite(OUTPUT_PIN, toggle);
  TCNT1  = 0;
  interrupts(); 
 
}

void Output_Begin()
{
  i_timer=0;
  toggle=false;
  digitalWrite(OUTPUT_PIN, toggle);
  Next_OCR=BEGIN_LEVEL_DURATION;
  // initialize timer1 
    noInterrupts();           // disable all interrupts
  
    TCCR1A = 0;
    TCCR1B = 0;
    TCNT1  = 0;
    
    OCR1A = BEGIN_LEVEL_DURATION;            // compare match register 16MHz/8/2Hz
    TCCR1B |= (1 << WGM12);   // CTC mode
    TCCR1B |= (1 << CS11);    // 8 prescaler
    TIMSK1 |= (1 << OCIE1A);  // enable timer compare interrupt
    TCNT1  = 0;
  
    interrupts();             // enable all interrupts

    
  while(1)
  {   
    if(i_timer==1)
    {
      //Next_OCR=begin_array[0];
      //Serial.println(i_timer);
      Next_OCR=BEGIN_BREAK;
      delay(.1);
    }
    else if(i_timer==2)
    {
      //Serial.println(i_timer);
      //Next_OCR=begin_array[1];
      Next_OCR=LEVEL_DURATION;
      delay(.1);
    }
    else if(i_timer>2)
    {
      return;
    }
    
  }
  return;
}
3

Im guessing English isn’t your first language…

You may have more luck if you pose your question in the language specific section of the forum.

4

This kind of problem with interrupts often means that you forgot to declare a variable 'volatile'. You didn;t show your declarations so it's hard to tell which one.

1 Like
5

Interrupts are automatically disabled inside an ISR and are automatically enabled when the ISR returns DO NOT disable and enable interrupts in an ISR.

1 Like
6

Thank you very much. That was the solution for my problem. You can’t imagine how much that helped me.

7

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