Arduino 串口测试 电脑发数据接收后立马返回

String comdata = "";

void setup() {
    Serial.begin(9600);
    while(Serial.read()>= 0){} //clear serialbuffer
    pinMode(13, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {

   if(Serial.available()>0){
      delay(1);
      comdata = Serial.readString();
   //   Serial.print("Serial.readString:");
  //    Serial.println(comdata);
      if(comdata=="1") {  Serial.println("ok");     digitalWrite(13, LOW); delay(1);   digitalWrite(13, HIGH);  delay(1);digitalWrite(13, LOW);  }
    }
    comdata = "";

}