void setup() {
  volatile char * dirf=0x30;
  volatile char * dirk=0x107;
  *dirf=0xFF;
  *dirk=0x0F;
  Serial.begin(9600);
}

void loop() {
  const char  segments[] = {
    0x3F, // 0
    0x06, // 1
    0x5B, // 2
    0x4F, // 3
    0x66, // 4
    0x6D, // 5
    0x7D, // 6
    0x07, // 7
    0x7F, // 8
    0x6F  // 9
};

char digit_on[4]={0x0E,0x0D,0X0B,0x07};
unsigned volatile char * outf=0x31;
unsigned volatile char * outk=0x108;
for(long i=0;i<10000;i++){
  int digits_i[4]={0};
  int k=3;
  long x=i;
  while(x!=0){
    int rem=i%10;
    digits_i[k]=rem;
    x=x/10;
    k--;
  }
  

 for(int l=0;l<200;l++)
  for(int j=0;j<4;j++){
    *outk=digit_on[j];
    *outf=segments[digits_i[j]];
    delay(5);
  }
  *outf=0x00;


}


}