#include <avr/io.h>

// Last modified: 26 October 2006
// Changed to work with WinAVR 20060421
// modified: 21 April 2005


// Compiled on WinAVR 20060421

//---------------------
// function prototypes
void delay(void);
int main(void);
//---------------------


//this function does nothing for about 1/20th of a second.
//a variable is set to 50000 and then counted down to zero.
void delay(void)
{
uint32_t waitcounter;
	waitcounter = 50000;	
	while(0 != waitcounter) {
		waitcounter--;
	}	
}

int main(void)
{
uint8_t countval;
int i;
//---------
// initialise the hardware
	DDRB = 0xff; //sets port b (pins 12 through 19) to be output
	PORTB = 0X0f; //the initial value on port b

//---------
// initialise the count value
	countval = 0;

//---------
// the main loop
	while(1) {
// the delay
		delay();
// broadcasting the binary value of countval across portb while
// countval counts from 0 to 255 over and over.
		
		PORTB = countval;
		countval++;
if(countval>=255) countval = 0;
	}
//---------

}