// 定义引脚
const int loadPin = 2;
const int clockPin = 3;
const int dataPin = 4;

void setup() {
  // 初始化串口通信
  Serial.begin(9600);

  // 设置引脚模式
  pinMode(loadPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, INPUT);

  // 初始状态
  digitalWrite(loadPin, HIGH);
  digitalWrite(clockPin, LOW);
}

void loop() {
  byte buttonStates = readButtons();

  // 检测每个按钮是否按下
  for (int i = 0; i < 8; i++) {
    if (bitRead(buttonStates, i) == 1) {
      Serial.print("按钮 D");
      Serial.print(i);
      Serial.println(" 被按下了");
    }
  }

  // 打印每个按钮状态
  for (int i = 0; i < 8; i++) {
    Serial.print(bitRead(buttonStates, i));
    Serial.print(" ");
  }
  Serial.println();
  delay(50);
}

byte readButtons() {
  byte states = 0;
  // 加载数据
  digitalWrite(loadPin, LOW);
  delayMicroseconds(2);
  digitalWrite(loadPin, HIGH);

  // 读取数据
  for (int i = 0; i < 8; i++) {
    states |= (digitalRead(dataPin) << i);
    digitalWrite(clockPin, HIGH);
    delayMicroseconds(2);
    digitalWrite(clockPin, LOW);
  }
  return states;
}