AVR Hello World

test.c

/* Borrowed from: http://wiki.hacdc.org/index.php/AVR_Lesson:_Output_Pins_I */
/* Blinker Demo */

#include <avr/io.h>		/* Defines pins, ports, etc */
#define F_CPU 8000000UL	   	/* Sets up the chip speed for delay.h */
#include <util/delay.h>		/* Functions to waste time */

#define LED PB1			/* Defines pin PB4 for the LED.  I
				   often incorporate a bunch of the circuit
				   info in the defines, which makes
				   porting the code to another chip
				   easier and reminds you of how to
				   hook it up. */

int main(void){

  DDRB = _BV(LED);		/* Data Direction Register B:
				   writing a one to the bit
				   enables output. */

  while(1){			/* the main loop, from which we never return */

    PORTB = _BV(LED); 		/* Turn on the LED bit/pin in PORTB */
    _delay_ms(400);	 	/* wait */

    PORTB &= ~_BV(LED);		/*  Turn off the LED bit/pin in PORTB */
   _delay_ms(400);		/* wait */

  }

  return(0);			/* never reached */
}