// #define LED 2
// int BTN_PIN = 19;

// void setup() {
//   pinMode(LED, OUTPUT);
//   pinMode(BTN_PIN, INPUT_PULLUP);

// }

// void loop() {
//   if (digitalRead(BTN_PIN) == LOW) {
//     digitalWrite(LED,(!digitalRead(LED)));
//   }
  
// }
int LED=2;
int btn = 12;
//int buttonState = 0;
void setup() {
  Serial.begin(115200);
  pinMode(LED, OUTPUT);
  digitalWrite(LED, LOW);
  Serial.print("初始化LED电平为：");
  Serial.println(digitalRead(LED));
  pinMode(btn,INPUT_PULLUP);
}

void loop() {
  if (digitalRead(btn)) {
    while (digitalRead(btn)) {
     delay(100);
    }
    digitalWrite(LED,(!digitalRead(LED)));

  }
  Serial.print(btn);
  Serial.print("赐予LED电平");
  Serial.println(digitalRead(LED));
  delay(100);
}