Miscellany

#include <avr/io.h>#include <avr/interrupt.h>#include <stdint.h>int8_t prevState;SIGNAL(SIG_INTERRUPT0){uint8_t port = PORTA;uint8_t pressed = port & ~prevState;prevState=port;        if(pressed == 0)                PORTD ^=(1<<PD6);        if(pressed==1)                PORTD ^=(1<<PD5);}int main(void){        GICR=0xC0;        MCUCR=0x01;        sei();        DDRD |= (1<<PD6)|(1<<PD5);        PORTD |= (1 << PD2);        PORTA |=(1<<PA0)|(1<<PA1)|(1<<PA2)|(1<<PA3)|(1<<PA4)|(1<<PA5)|(1<<PA6)|(1<<PA7);        while (1) {        }        return 0;}