// 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)

unsigned long curMillis = 0;
int interval = 200; // Set the number dwell time before changing

int btnUp = 2;
int btnDown = 3;
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]);
  shiftOut(dataPin, clockPin, LSBFIRST, arrNums[0]);
  shiftOut(dataPin, clockPin, LSBFIRST, arrNums[0]);
  digitalWrite(latchPin, HIGH);
}
  
void setup() 
{
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  pinMode(btnUp, INPUT_PULLUP);
  pinMode(btnDown, INPUT_PULLUP);
  pinMode(btnReset, INPUT_PULLUP);
  Serial.begin(9600);
  setZero();
}



// --- Use the buttons: red = decrement, green = increment
void loop(){
  if(digitalRead(btnUp) == LOW || digitalRead(btnDown) == LOW ){
    if(digitalRead(btnUp) == LOW){
      loopCount++;
      loopCount = (loopCount > 999) ? 0 : loopCount;
    }else{
      loopCount--;
      loopCount = (loopCount <= 0) ? 999 : 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();
  }
}