#define DATA_PIN      8
#define LATCH_PIN     9
#define CLOCK_PIN     10
#define COMMON_PIN    2 // Common pin for SSDs
#define MAX_SSD       4

// Segment byte maps for numbers 0-9
const byte digitMap[10] = {
  0b11000000, // 0
  0b11111001, // 1
  0b10100100, // 2
  0b10110000, // 3
  0b10011001, // 4
  0b10010010, // 5
  0b10000010, // 6
  0b11111000, // 7
  0b10000000, // 8
  0b10010000  // 9
};

void setup() {
  // Set pin modes
  pinMode(DATA_PIN, OUTPUT);
  pinMode(CLOCK_PIN, OUTPUT);
  pinMode(LATCH_PIN, OUTPUT);
  pinMode(COMMON_PIN, OUTPUT);
}

void displayDigit(int digit) {
  digitalWrite(LATCH_PIN, LOW); 
  shiftOut(DATA_PIN, CLOCK_PIN, MSBFIRST, digitMap[digit / 10]); 
  shiftOut(DATA_PIN, CLOCK_PIN, MSBFIRST, digitMap[digit % 10]); 
  digitalWrite(LATCH_PIN, HIGH);
  digitalWrite(COMMON_PIN, HIGH);
}

void loop() {
  for (int count = 0; count < 100; count++) 
  {
    displayDigit(count);;
    delay(900);

  }
}