Also im Simulator funktioniert es bei mir!
Code:
/*
 * Servopuls.cpp
 *
 * Created: 06.09.2021 19:19:49
 * Author : USER
 */ 

/**********            ATtiny84A 8MHz           ***************/



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




#define F_CPU 8000000UL




uint16_t start_puls,end_puls,laenge_puls;
uint8_t steigend, fallend;




void init_timer_0 (void)
{
    TCCR0A = 0x00;
    TCCR0B = (1<<CS01) + (1<<CS00);
    TIMSK0 = (1<<TOIE0) ;
    TCNT0 =131;




}




void init_timer_1(void)
{
    TCCR1A=0x00;
    TCCR1B= (1<<CS11);
    
}


ISR (INT0_vect)
{
    if (steigend == 1)
    {
        start_puls=TCNT1;
        steigend=0;
        MCUCR |= (1<<ISC01);
        MCUCR &= ~(1<<ISC00);
    }
    else
    {
        end_puls=TCNT1;
        laenge_puls=end_puls-start_puls;
        steigend=1;
        MCUCR |= (1<<ISC01);
        MCUCR |= (1<<ISC00);
    }
    
}

int main(void)
{
    init_timer_1();
    
    DDRA = 0xFF;
    
    DDRB &= ~(1<<PORTB2);
    MCUCR |= (1<<ISC01) | (1<<ISC00); // INT0 auf  steigende Flanke
    GIMSK |= (1<<INT0);
    
    sei();
    
    while(1)
    {
        if (laenge_puls<1300)
        {
            PORTA = 0b00000001;
        }
        if ((laenge_puls>1300)&&(laenge_puls<1700))
        {
            PORTA = 0b00000010;
        }
        if(laenge_puls>1700)
        {
            PORTA = 0b00000100;
        }
    }
}