//Pin connected to ST_CP of 74HC595
int latchPin = 10;

//Pin connected to SH_CP of 74HC595
int clockPin = 12;

////Pin connected to DS of 74HC595
int dataPin = 11;

//            dGFEDCBA
uint8_t segment[] = {
           0b00111111, //0
           0b00000110, //1
           0b01011011, //2
           0b01001111, //3
           0b01100110, //4
           0b01101101, //5
           0b01111101, //6
           0b00000111, //7
           0b01111111, //8
           0b01101111  //9
};

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


/*
 * https://docs.arduino.cc/language-reference/en/functions/advanced-io/shiftOut/
 */
void loop() 
{
  //count up routine
  for (int j = 0; j < 100; j++) 
  {
    //ground latchPin and hold low for as long as you are transmitting
    digitalWrite(latchPin, LOW);
    
    shiftOut(dataPin, clockPin, MSBFIRST, 255 - segment[(j % 10)]);
    shiftOut(dataPin, clockPin, MSBFIRST, 255 - segment[(j / 10)]);
    shiftOut(dataPin, clockPin, MSBFIRST, 0);
    shiftOut(dataPin, clockPin, MSBFIRST, 1);

    //return the latch pin high to signal chip that it
    //no longer needs to listen for information
    digitalWrite(latchPin, HIGH);
    delay(300);
  }

}