마이크로프로세서 avr 서보모터 질문드립니다

#include<avr/io.h>

#include<avr/interrupt.h>

volatile unsigned char count=0;

volatile unsigned char timer_flag=0;

volatile unsigned char job=0;

volatile unsigned char job1=0;

volatile unsigned long High_table[18]={1389,1599,1799,1999,2199,2400,2599,2796,3002,3199,3401,3596,3802,3999,4201,4394,4596};

volatile unsigned long Low_table[18]={38599,38399,37999,37799,37599,37399,37199,36999,36799,36599,36399,36199,35999,35799,355599,35399};

volatile unsigned char temp=0;

volatile unsigned char temp2=0;

volatile unsigned char val=0;

void init_timer1()     

{

    TCCR1B=0x0A;

OCR1A=39999; 

TIMSK  |= (1<<OCIE1A);      

}

void init_timer2()     

{

  

    TCCR3B=0x0A;

OCR3A=39999; 

ETIMSK |= (1 << OCIE3A); 

}

int main(void)

{

cli();

DDRG=0xff;

DDRA=0xff;

DDRE = 0xFE;

ADMUX = (0<<REFS1) | (1<<REFS0) | (1<<ADLAR); 

ADCSRA = (1<<ADEN) | (1<<ADPS2) ;

init_timer1();

init_timer2();

sei();

while(1)

{

ADCSRA |= 0x40;

while((ADCSRA & 0x10) == 0);

temp=ADCL;

temp=ADCH;

}

return 0;

}

ISR(TIMER1_COMPA_vect)

{

OCR1A=39999; 

ADMUX= (ADMUX & 0xF8) + 0x00;

if(temp==255)

{

if(job)

{

job=0;

OCR1A=High_table[0]; 

PORTG=0xff; 

}

else

{

job=1;

    OCR1A=Low_table[0]; 

PORTG=0x00; 

}

}

}

ISR(TIMER3_COMPA_vect)

{

  OCR1B=39999; 

ADMUX= (ADMUX & 0xF8) + 0x01;

if(temp==0)

{

if(job1)

{

job1=0; 

OCR3A=High_table[1]; 

PORTA=0xff; 

}

else

{

job1=1;

    OCR3A=Low_table[1]; 

PORTA=0x00; 

}

}

}

제가 짠 프로그램인데 조이스틱을 이용해서 들어오는 adc 값 가지고 펄스를 내보내려고 합니다.

근데 ISR(TIMER1_COMPA_vect) 하나만 인터럽트 할때는 정상적으로 되는데 ISR(TIMER3_COMPA_vect)