#include <avr/io.h>
#include <Arduino.h>

int main(void)
{
  DDRB |= (1 << 5); // Set LED as output
  TCCR1B |= (1 << CS12 ); // Set up timer with the prescaler of 256
  TCCR1B |= (1 << WGM12); // Turn on the CTC mode for Timer   
  OCR1A = 31249;    // Set CTC compare value to 5Hz at 16 MHz AVR clock , with a prescaler of 256
  while (1)
  {
    if (TIFR1 & (1<<OCF1A))  //Check if Compare Match
    //F here means flag
    {
      PORTB ^= (1 << 5); // Toggle the LED
      TIFR1 |= (1<<OCF1A);    //Clear the flag
  }
}
}

//this configuration does not need to use the 
//the pin 13 also controls the built in LED (L)