74HC165 PISO shift register example for Arduino

pisoshiftreg.ino

#define CSPIN 2
#define CLKPIN 3
#define DPIN 4

void setup() {
  pinMode(CSPIN, OUTPUT);
  pinMode(CLKPIN, OUTPUT);
  pinMode(DPIN, INPUT);
  
  Serial.begin(115200);
}

void loop() {
  int buf[4];
  digitalWrite(CLKPIN, HIGH); // Make sure clock is high so first transition is "skipped"
  digitalWrite(CSPIN,HIGH); // Latch
  // Set clock enable low here if used
  Serial.println("Data:");
  
  for(int i = 0;i<4;i++){
    buf[i] = shiftIn(DPIN,CLKPIN,LSBFIRST ); // Shift 1 byte in
    Serial.println(buf[i],BIN);
  }
  digitalWrite(CSPIN,LOW); // Latch low
  digitalWrite(CLKPIN, LOW);
  // Set clock enable high here if used
  Serial.print('\n');
  
  delay(100);
}