//共用變數放這裡
int D=1000,ND=0;
int mode=0,flag=0;
unsigned long T,T1;
void setup() { 
  //設定區，一開始執行一次
  pinMode(13, OUTPUT);//
  Serial.begin(115200);
  pinMode(2, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(2), resetD, FALLING);
  T=0;T1=0;
}
void resetD(){
  D=1000;
  if (flag==1){
    flag=0;
    digitalWrite(13, LOW); 
  }
  else{
    flag=1;
    digitalWrite(13, HIGH); 
  }
}
void loop() {
  //主要程式區，此區會不斷的重複執行  
  if (millis()-T>D){
    if (flag==0){
      digitalWrite(13, HIGH); 
      flag=1;
    }
    else {
       digitalWrite(13, LOW); 
       flag=0;
    }
    T=millis();
  }
}
void serialEvent() {
  while (Serial.available()) {
    char inc = (char)Serial.read();//將byte轉成 char
    if (mode==0 && inc=='S')  {
      mode=1;
      ND=0;
    }
    if (mode==1 && inc=='E'){
      D=ND;
      mode=0;
      ND=0;
      Serial.print("now D=");
      Serial.println(D);
    }
    if (mode==1 &&(inc>='0'&& inc<='9')){
      ND=ND*10+(inc-'0');
    } 
  }
}