// Blink.c

#include <avr/io.h>
#include <util/delay.h>     // _delay_ms()

// ----------------------------------------------

#define SHORT_DELAY     125
#define LONG_DELAY      333
#define F_CPU           16000000UL

    
int main(void) 
{ 
    DDRA = 0XFF ;
    DDRB = 0xFF ;       // Make outputS.
    DDRC = 0XFF ;
    DDRD = 0XFF ;
    
    PORTA = 0xFF ;
    PORTB = 0xFF ;
    PORTC = 0xFF ;
    PORTD = 0xFF ;
    
    PORTA = 0x00 ;
    PORTB = 0x00 ;
    PORTC = 0x00 ;
    PORTD = 0x00 ;
    
    //-----
    
    while (1)
    {   
        PORTA = 0xFF ;
        PORTB = 0xFF ;
        PORTC = 0xFF ;
        PORTD = 0xFF ;
        _delay_ms( 125 ) ;
        
        PORTA = 0x00 ;
        PORTB = 0x00 ;
        PORTC = 0x00 ;
        PORTD = 0x00 ;
        _delay_ms( 333 ) ;
    } ;
}