int dataPin = 9;   // SER
int clockPin = 8;  // SRCLK
int latchPin = 4;  // RCLK

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

void loop() {
  // All LEDs ON
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, 255); // 11111111
  digitalWrite(latchPin, HIGH);
  delay(1000);

  // All LEDs OFF
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, 0);   // 00000000
  digitalWrite(latchPin, HIGH);
  delay(1000);
}