const int dataPin = 2;  
const int clockPin = 3; 
const int latchPin = 4; 

void setup() {
  pinMode(dataPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(latchPin, OUTPUT);
}

void loop() {
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, 0xFF); 
  digitalWrite(latchPin, HIGH);
}