// NOTE: DEMO ONLY!!
// Each LED segment should be current limited with a 220ohm resistor
// The clock pin of the shift registers (SHCP) must be connected to
// the GND via a 100nF ceramic capacitor

int latchPin = 8;//Pin connected to ST_CP of each shift register
int clockPin = 12;  //Pin connected to SH_CP of each shift register
int dataPin = 11; //Pin connected to DS of first shift register
// Connect Q7S of the first shift register to DS of the next register(s)

int interval = 200; // Set the number dwell time before changing

int btnReset = 13;
int loopCount = 0;

byte arrNums[] = {
  B11111100, B01100000, B11011010,
  B11110010, B01100110, B10110110,
  B10111110, B11100000, B11111110,
  B11110110
};

// Set initial state (lit up with 0's) or return to zero with the reset button
void setZero() {
  loopCount = 0;
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, LSBFIRST, arrNums[0]);
  digitalWrite(latchPin, HIGH);
}

void setup()
{
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  pinMode(btnReset, INPUT_PULLUP);
  Serial.begin(9600);
  setZero();
}



// --- Use the buttons: red = decrement, green = increment
void loop() {
  loopCount++;
  loopCount = (loopCount > 999) ? 0 : loopCount;
  digitalWrite(latchPin, LOW);
  // If using common anode, xor array values to flip the bits
  /*
    shiftOut(dataPin, clockPin, LSBFIRST, arrNums[loopCount%10] ^ B11111111);
    shiftOut(dataPin, clockPin, LSBFIRST, arrNums[loopCount/10%10] ^ B11111111);
    shiftOut(dataPin, clockPin, LSBFIRST, arrNums[loopCount/100%10] ^ B11111111);
  */
  shiftOut(dataPin, clockPin, LSBFIRST, arrNums[loopCount % 10]);
  shiftOut(dataPin, clockPin, LSBFIRST, arrNums[loopCount / 10 % 10]);
  shiftOut(dataPin, clockPin, LSBFIRST, arrNums[loopCount / 100 % 10]);
  digitalWrite(latchPin, HIGH);
  delay(interval);
  if (digitalRead(btnReset) == LOW) {
    setZero();
  }
}