void setup() {
  // put your setup code here, to run once:
  volatile char *dirf,*dirk;
  volatile char *outf,*outk;
  volatile long i;

  dirf = 0x30;    dirk = 0x107;
   outf = 0x31;   outk = 0x108;

  *dirf = 0x03;  
  *dirk = 0x03;
  
  while(1){

   *outk = 0x02;  
   *outf = 0x01;
  
  for(i=0;i<500000;i++);
   *outk = 0x01; 
   *outf = 0x01;

   for(i=0;i<500000;i++);
   *outk = 0x01; 
   *outf = 0x02;

   for(i=0;i<500000;i++);

   *outk = 0x02; 
   *outf = 0x02;
   for(i=0;i<500000;i++);
  }
   //try changing order

   //try removing while loop
}

void loop() {
  // put your main code here, to run repeatedly:

}