atmega8 timer2 - use CTC/output compare interrupt w/o usage of OC2 pin

atmega8_timer2.c

// All values/comments are valid with ATmega8 running at Fosc = 4.000MHz

#include <avr/io.h>
#include <avr/interrupt.h>

// TIMER2 with prescaler clkT2S/1024
#define TIMER2_PRESCALER      (1 << CS22) | (1 << CS21) | (1 << CS20)

// TIMER2 output compare value
// --> value 98 is 25.088ms (4MHz@1024 prescale factor)
#define TIMER2_COMPARE_VALUE  98


void main()
{
   // ... do something ...

   // init Timer2
   TIMSK |= (1 << OCIE2);                    // set output compare interrupt enable
   TCCR2 |= (1 << WGM21) | TIMER2_PRESCALER; // set CTC mode
   OCR2   = TIMER2_COMPARE_VALUE;            // set compare value for interrupt
   sei();                                    // global interrupt enable

   // ... do something ...

   while (1)
   {
      // ... do something ...

   } /* end of while(1)  */
}

// *** Interrupt Service Routine *****************************************

// Timer2 compare match interrupt handler
// --> set as 25ms
ISR(TIMER2_COMP_vect)
{
   // handle interrupt
}