请问这段编程烧录后，LED为何在开关按下时无法关闭？

4接的是按钮，9接的是LED。
求大神解答！拜谢！

const int LED = 9;
int i = 0;
const int BUTTON = 4;
boolean state = 0;
int val = 0;
int oldvalue = 0;

void setup() {
  pinMode(LED,OUTPUT);
  pinMode(BUTTON,INPUT);
}

void loop() {
  val = digitalRead(BUTTON);
  if( (val == HIGH) && (oldvalue == LOW)){
    state = !state;
    delay(10);
  }
  oldvalue = val;

  if (state ==1){
    for(i=0; i<255; i++){
      analogWrite(LED, i);
      delay(10);
    }

    for (i=255; i>0; i--){
      analogWrite(LED,i);
      delay(10);
    }
  }else if(state == 0){
  analogWrite(LED, 0);
  }
}

不懂帮顶

dsweiliang 发表于 2016-3-1 08:41
不懂帮顶

谢谢