#include <avr/io.h> #define F_CPU 16000000UL // Crystal Freq. #define TIMER_CLOCK 2 // Toggling Freq. int main() { DDRD = _BV(PD5); // set OC1A pin as output, required for output TCCR1A = _BV(COM1A0); // enable toggle OC1A output on compare TCCR1B = _BV(CS10) | _BV(CS11) | _BV(WGM12); // prescaler=64, clear timer/counter on compareA match OCR1A = ((F_CPU / 64) / (2 * TIMER_CLOCK)) - 1; // preset timer1 high/low byte /* * Initialisation done, LED will now flash without executing any code! */ while(1) // Infinite loop { } return 0; }