#include <Arduino.h>

const int dataPin  = 16; /* Q7 */
const int clockPin = 17; /* CP */
const int latchPin = 18; /* PL */

const int numBits = 16; /* Set to 8 * number of shift registers */

void setup() {
    Serial.begin(115200);
    pinMode(dataPin, INPUT);
    pinMode(clockPin, OUTPUT);
    pinMode(latchPin, OUTPUT);
}

void loop() {
    // Step 1: Sample
    digitalWrite(latchPin, LOW);
    digitalWrite(latchPin, HIGH);

    // Step 2: Shift
    Serial.print("Bits: ");
    for (int i = 0; i < numBits; i++) {
        int bit = digitalRead(dataPin);
        if (bit == HIGH) {
            Serial.print("1");
        } else {
            Serial.print("0");
        }
        digitalWrite(clockPin, HIGH);  // Shift out the next bit
        digitalWrite(clockPin, LOW);
    }

    Serial.println();
    delay(1000);
}