shiftFunction.ino

int CLOCK_PIN = 10;
int DATA_PIN = 11;
int LATCH_PIN = 12;

void setup() {

  pinMode(CLOCK_PIN, OUTPUT);
  pinMode(DATA_PIN, OUTPUT);
  pinMode(LATCH_PIN, OUTPUT);

}

void loop() {

  sendByteOut(B11110000);
  delay(1000);
  sendByteOut(B00001111); 
  delay(1000);
  
}

void sendByteOut(byte value){

  //shiftOut(dataPin, clockPin, bitOrder, value)
  
  digitalWrite(LATCH_PIN, LOW); //set the latch to low so we can raise it later
  digitalWrite(CLOCK_PIN, LOW); //make sure clock pin is low before we start
  shiftOut(DATA_PIN, CLOCK_PIN, LSBFIRST, value); //Shift out the data
  digitalWrite(LATCH_PIN, HIGH); //Latch the data in
}