#include <iostm8s103f3.h>

main( void )
{
  PD_DDR = 0x0f; //sets port to output mode
  while(1){
    PD_ODR_ODR3 = 1; //turns pin3 on

    //delay
    int k = 0;
    for(int i = 0; i < 1000000; i++){
      k++;
    }

    PD_ODR_ODR3 = 0; //turns pin3 off
  }
}