Serial Call and Response (handshaking) —— Arduino Documentation

Serial Call and Response (handshaking) —— Arduino Documentation

原来的例子用到了传感器。如果仅仅只关注通信的握后，可以改造一下，改为只在串口发送和接收数据。

设计题： 模拟停等协议或 TCP 建立连接的协议，实现串口间的大量数据传输。

原始代码：

int firstSensor = 0;    // first analog sensor
int secondSensor = 0;   // second analog sensor
int thirdSensor = 0;    // digital sensor
int inByte = 0;         // incoming serial byte


void setup() {
  // start serial port at 9600 bps:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

  pinMode(2, INPUT);   // digital sensor is on digital pin 2
  establishContact();  // send a byte to establish contact until receiver responds
}


void loop() {
  // if we get a valid byte, read analog ins:
  if (Serial.available() > 0) {
    // get incoming byte:
    inByte = Serial.read();      // 1  ??? 
    // read first analog input, divide by 4 to make the range 0-255:
    firstSensor = analogRead(A0) / 4;
    // delay 10ms to let the ADC recover:
    delay(10);
    // read second analog input, divide by 4 to make the range 0-255:
    secondSensor = analogRead(1) / 4;
    // read switch, map it to 0 or 255L
    thirdSensor = map(digitalRead(2), 0, 1, 0, 255);
    // send sensor values:
    Serial.write(firstSensor);
    Serial.write(secondSensor);
    Serial.write(thirdSensor);
  }
}


void establishContact() {
  while (Serial.available() <= 0) {
    Serial.print('A');   // send a capital A
    delay(300);
  }
}

代码的握手看起来有些简单。

inByte = Serial.read() 所读到的值后面没有用到啊？原始代码中还有 processing 代码，用到了 read 的值，且握手更复杂。