void time_delay(void);

int main(void)
{
  // Configure PORTS Direction PORTF
  volatile char *dirf;
  dirf = (char *) 0x30;
  *dirf = 0xFF;
     
  // Setup output register of PORTF
  volatile char *outf;
  outf = (char*) 0x31;

  // Array containing seven segment values to display A to F
  unsigned char sev_seg[] = {0x77, 0x7C, 0x39, 0x5E, 0x79, 0x71};
  unsigned char size = (unsigned char) sizeof(sev_seg)/sizeof(sev_seg[0]);

  while (1)
  {
    for (char i = 0; i < size; i++)
    {
      *outf = sev_seg[i];
      time_delay();
    }
  }
}

void time_delay(void)
{
  volatile long del = 0;
  while (del++ < 500000);
}