void freg1(void){
    TCCR1B=(0<<ICES1)|(0<<CS10);//stop
    TCNT1=0;
    TIFR =(1<<TOV1);
    TIMSK &=~_BV(TOIE1);
    nover=0;
    mover=0;
    TCCR1B=(0<<ICES1)|(1<<CS10);//start
    TIFR=(1<<ICF1);
    while((TIFR&_BV(ICF1))==0);       
    if(TIFR &_BV(TOV1))              
        {                                
        nover++;                        
        TIFR =_BV(TOV1);                
        }
    ntick2=nover;
    ntick1=ICR1;
    TIMSK |=_BV(TOIE1);
    mtick1=TCNT0;                  
    mtick2=mover;
    N1=((uint32_t)(ntick2)<<16)+(uint32_t) ntick1; //системные тики
    M1=((uint32_t)(mtick2)<<8) +(uint32_t) mtick1; //входные тики
}

void freg2(void){
    while(TCNT1<65525);
    asm("nop");
    asm("nop");
    asm("nop");
    asm("nop");
    asm("nop");
    asm("nop");
    asm("nop");
    asm("nop");
    asm("nop");
    asm("nop");
    
    TIFR=(1<<ICF1);
    while((TIFR&_BV(ICF1))==0);
    ntick2=nover;
    ntick1=ICR1;
    mtick1=TCNT0;                    
    mtick2=mover;                
    N2=((uint32_t)(ntick2)<<16)+(uint32_t) ntick1;
    M2=((uint32_t)(mtick2)<<8) +(uint32_t) mtick1;
    N=N2-N1;                          
    M=M2-M1;                      
    Fx=12000000.0*(float)M/(float)N;
}