Frequenz Umsetzer mit AtTiny85

#include <avr/io.h>

#include <avr/interrupt.h>

#define F_CPU           8000000L

volatile long count1_ovf=1;

volatile int count1_ovf_tmp=1;

volatile long count1_counts=1;

volatile int count1_rest=1;

volatile long count_mess_ovf=0;

volatile int countok=0;

volatile int flanke2=0;

volatile int count1_a=0;

volatile int count1_b=0;

void setup()

{

  GIMSK = 0b00100000;    // turns on pin change interrupts

  PCMSK = 0b00000001;    // turn on interrupts on pins PB0, PB1, & PB4

    DDRB = 0b00010000;

//  TCCR1 |= (1<<CS10); /* CPU/16384 als Takt */

  TIMSK |= (1<<TOIE0 | 1<<TOIE1);  /* Overflow Interrupt an */

//  TCCR0B |= (1<<CS00); /* CPU/16384 als Takt */

  sei();                 // enables interrupts

//  cli();

}

int main(void)

{

  setup();

    while (1)

    {

  if (count_mess_ovf >=30000){

    TCCR0B &= ~(1<<CS00); /* CPU/16384 als Takt */

    TCCR1 &= ~(1<<CS10); /* CPU/16384 als Takt */

    count_mess_ovf=0;

    count1_ovf=1;

    count1_counts=1;

    count1_rest=1;

    countok=0;

    count1_ovf_tmp=1;

    flanke2=0;

    count1_a=0;

    count1_b=0;

    TCNT0 = 0;

    TCNT1 = 0;

    //DDRB = 0b00000000;

    }

    }

}

ISR(PCINT0_vect)

{

  if (PINB & ( 1 << PIN0 ) ) {

    TCCR1 |= (1<<CS10); /* CPU/16384 als Takt */

    TCCR0B |= (1<<CS00); /* CPU/16384 als Takt */

      //DDRB = 0b00010000;

    count1_b = TCNT1 - count1_a;

    count1_counts = (count1_b + ( 255 * count_mess_ovf )) / 2;

    count_mess_ovf = 0;

    count1_counts = count1_counts * 1.07;

    count1_ovf = count1_counts / 255;

    count1_rest = count1_counts - ( 255 * count1_ovf );

    count1_a = TCNT1;

  }

}

ISR(TIMER0_OVF_vect)

{

  count_mess_ovf++;

}

ISR(TIMER1_OVF_vect)

{

  if (countok == 1 && count1_ovf >= 1){

    PINB = _BV(PB4);

    count1_ovf_tmp = count1_ovf;

    countok=0;

  }

  if (count1_ovf_tmp == 0) {

    TCNT1 = 255 - count1_rest;

    countok=1;

    }

  else { count1_ovf_tmp--; }

}