인터럽트 LED 카운터

#include 
#include 

unsigned char led;

interrupt [2] void exint0(void)
{
    PORTC = ~(++led); 
    delay_ms(5);
}

void main(void)
{
    DDRC = 0xff; 
    DDRD = 0x00; 
    SREG.7 = 1; 
    EIMSK = 0b00000001; 
    EICRA = 3; 
    PORTC = ~led;
    for(;;); 
}