#include <stdio.h>
#include <stdlib.h>
#include <xc.h>

void delay()
{
    int counter = 0xFF;
    while(counter) counter = counter - 1;
}
int main(void)
{
    ANSELA = 0xF0;
    TRISA = 0x00;
    PORTA = 0xFF;

    while(1)
    {
        PORTAbits.RA0 = 1;
        delay();
        PORTAbits.RA0 = 0;
        delay();
    }
}