#define DDRB (*(volatile unsigned char *)(0x37))
#define PORTB (*(volatile unsigned char *)(0x38))

#define SREG (*(volatile unsigned char *)(0x5f))

#define TIMSK (*(volatile unsigned char *)(0x59))
#define TIFR (*(volatile unsigned char *)(0x58))
#define TCCR0 (*(volatile unsigned char *)(0x53))
#define TCNT0 (*(volatile unsigned char *)(0x52))

#define GIMSK (*(volatile unsigned char *)(0x5b))
#define MCUCR (*(volatile unsigned char *)(0x55))

#define ENTRADA 0xff
#define SAIDA 0x00

#define ACENDE 0x00
#define APAGA 0xff

#define IRQ0 __vector_1
#define IRQ7 __vector_7
#define SIGNAL __attribute__ ((signal))

int counter; //contador de overflows

int main(void) {
    counter = 0;

    SREG = 0x80;  //habilita as interrupções

    GIMSK = 0x40;
    MCUCR = 0x02; //habilita interrupção ao precionar o botao

    DDRB = ENTRADA;
    PORTB = APAGA;

    while(1) {}
    return 0;
}

void IRQ0(void) SIGNAL;

void IRQ0(void) {
  static is_down = 0; //indica se o botão foi precionado ou liberado

  is_down = ~is_down;
  if (is_down)
  {
    TIMSK = 0x02; //habilita interrupção de tempo
    MCUCR = 0x03; //habilita interrupção ao liberar o botao
    TCCR0 = 0x05; //overflow para 256
  }
  else 
  { 
    counter = 0;  //reseta o contador
    TCCR0 = 0x00;
    TIMSK = 0x00; //desabilita interrupção de tempo
    MCUCR = 0x02; //habilita interrupção ao precionar o botaoi
    TCNT0 = 0x00;
    PORTB = APAGA; 
  }
}

void IRQ7(void) SIGNAL;

void IRQ7(void) {
  counter++;  
  if (counter == 61)
  {
    counter = 0;
    PORTB = ACENDE;
  }
}