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

volatile uint8_t i;
int x;
ISR(PCINT0_vect)
{
  x = 1;
}
ISR(PCINT1_vect)
{
  x = 2;
}
int main (void)
{
  DDRA = 0xff;
  PORTB |= _BV(PB4); // pin PD.0 input pullup
  PORTJ |= _BV(PJ1); // pin PD.1 input pullup
  PCMSK0 |= (1<<PCINT4); // enable interrupt PCINT4; 
  PCMSK1 |= (1<<PCINT10); //enable interrupt PCINT10;
  PCICR |= _BV (PCIE0)| _BV (PCIE1); 
  sei();
  while (1) {
    switch (x) {
      case 0:
        PORTA = 0XFF;
        sei();
        break;
      case 1:
        i++;
        PORTA =~ i;
        _delay_ms(500);
        sei();
        break;
      case 2:
        i--;
        PORTA =~ i;
        _delay_ms(500);
        sei();
        break;
    }
  }
}