#include <inttypes.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/signal.h>
#include <stdlib.h>

#include <stdarg.h>
#include <ctype.h>
#include <string.h>

static volatile uint8_t led;

static void delay(uint16_t us) 
{
    while(us)
    	us--;
}

int main(void)
{
    // port B output
    DDRB = 0xff;
    
	led = 1;		    //init variable representing the LED state

    while(1)
    {
        if (led)
        {
            led = 0;
            PORTB = 0;
        }
        else
        {
            led = 1;
            PORTB = 0xff;
        }

        delay(50000);
        delay(50000);

    }
}