[AVR] 500ms delay using timer in ATMEGA8

[djc]

Hi,

Can somebody guide me how to generate 500 ms delay using any of the timer like Timer 0 or Timer 1 of ATMEGA8.

 

[nick703]

use this link and try to your self if any error then post .

https://sites.google.com/site/qeewiki/books/avr-guide/timer-on-the-atmega8

 

[jayanth.devarayanadurga]

For ATMEGA8 at 8 MHz Clock.

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Code C - [expand]
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//Timer1 Prescaler = 64; Preload = 62499; Actual Interrupt Time = 500 ms
 
//Place/Copy this part in declaration section
void InitTimer1(){
  SREG_I_bit = 1; 
  TCCR1A = 0x80;
  TCCR1B = 0x0B;
  OCR1AH = 0xF4; 
  OCR1AL = 0x23; 
  OCIE1A_bit = 1; 
}
 
void Timer1Overflow_ISR() org IVT_ADDR_TIMER1_COMPA {
  //Enter your code here 
}

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[djc]

Thank you jayanth and nick, i am able to generate 500ms interrupt now.

 

[djc]

hi jayanth,

I am again facing a problem in timer reload value. Now i want to generate 1sec output compare interrupt. So how to calculate timer reload value. Please guide me.

 

[alexan_e]

Seems like you didn't read the linked guide the previous time and you have just used the solution that was provided.

Here is another guide that explains everything about AVR timers https://www.github.com/abcminiuser/avr-tutorials/blob/master/Timers/Output/Timers.pdf?raw=true

 

[djc]

Thanx alexan,

I found the fault where i was actually lacking.