Arduino Nano Every的Serial1 readString通信异常求助

我正在使用Serial1在两台Arduino Nano Every之间建立通信通道，代码包含通用通信类serialCommunication及主循环。通过GPIO引脚txRxPin将设备配置为两种模式：RC（遥控站）发送字符串后等待工作站响应，Machine（工作站）接收数据后回复。

代码在硬件回环测试中运行正常，但跨接两台设备（Rx与Tx交叉连接）后，接收方法rxData出现问题：双方均无法正常接收数据，且Machine端的readString语句会卡住；添加延迟无效果，替换为循环读取字符的逻辑虽能运行，但会丢失部分字符。

控制台输出 #

Machine端初始输出 #

Init started
Init finished; station mode=machine station
TP rxData 1

RC重置后Machine端重复57次的输出 #

TP rxData 2 8001|8001|8001|409 as received on machine
from machine to rc as transmitted from machine

RC端输出 #

RC Transmission start at 55512
Transmitted from RC on RC: 8001|8001|8001|77
Error #78; loop time = 500
Communication in time #78/0 - no data; loop time = 500
TP loop RC 1

代码 #

#define VERBOSE

#include <Arduino.h>
/*****************************************************/
#define txRxPin 15
class serialCommunication {
public:
  void begin();
  bool txData(String txStr);
  bool rxData(String &rxStr);
  bool available() {
    Serial1.available();
  }
} Comm;

void serialCommunication::begin() {
  Serial1.begin(19200);
  while (!Serial1)
    ;
}

bool serialCommunication::txData(String txStr) {
  if (Serial1.available())
    return false;
  digitalWrite(txRxPin, true);  // If RS485 - transciever to TX mode
  Serial1.print(txStr);
  Serial1.flush();
  digitalWrite(txRxPin, false);  // If RS485 - transciever to TX mode
  return true;
}

bool serialCommunication::rxData(String &rxStr) {
  if (!Serial1.available())
    return false;
  while (digitalRead(txRxPin))
    ;
  Serial.println("TP rxData 1");
  rxStr = Serial1.readString();
  Serial.println("TP rxData 2");
  return rxStr.length() > 0;
}
/*****************************************************/
/*************   Main program   **********************/
/*****************************************************/
#define txInterval 500
uint32_t timing;
bool stationType;  // low - machine, high - remote control mode
int commError, previousPacketCounter, packetCounter;
String announcement;

/*****************************************************/
void setup() {
  Serial.begin(9600);
  while (!Serial)
    ;
  Serial.println("Init started");

  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, false);

  Comm.begin();
  pinMode(txRxPin, INPUT);
  timing = millis();
  packetCounter = 0;
  commError = 0;
  previousPacketCounter = 0;

  stationType = digitalRead(txRxPin);
  announcement = stationType ? "remote control station" : "machine station";
  Serial.println("Init finished; station mode=" + announcement);
  delay(1000);
}
/*****************************************************/
void loop() {
  digitalWrite(LED_BUILTIN, true);
  if (stationType) {
Serial.println("TP loop RC 1");
    //******************** remote controller
    if ((millis() - timing) > txInterval) {
      Serial.println("\n\nRC Transmission start at " + String(millis() - timing));
      String packet = "8001|";
      packet += packet + packet + String(packetCounter++);  // create the packet
      if (!Comm.txData(packet))                             // Transmit the packet
        packetCounter--;                                    // The packet was not transmittedso retain its number
#ifdef VERBOSE
      Serial.println("Transmitted from RC on RC: " + packet);
      Serial.flush();
#endif

      // Receive machine reply
      long txTimer = millis();
      while ((millis() - txTimer) < 10)
        ;  // Seria;1 settling time
      while (!Comm.available() && ((millis() - txTimer) < txInterval))
        ;
Serial.println("Error #" + String(++commError) + "; loop time = " + String((millis() - txTimer)));
      String rcRxBuffer;
      bool rFlag = Comm.rxData(rcRxBuffer);
#ifdef VERBOSE
      if (!rFlag) {
        Serial.println("Communication timeout, error# " + String(commError) + "/" + String(rFlag) + " - no data; loop time = " + String((millis() - txTimer)));
        return;
      }
      commError = 0;
#endif
      Serial.println("Communication succeeded; rFlag=" + String(rFlag) + "; loop time = " + String((millis() - txTimer)));
      Serial.println("Data=<" + rcRxBuffer + ">");
      //      Serial.println(rcRxBuffer + " as received by RC; loop time = " + String(millis() - txTimer));
      Serial.flush();
    }
  } else {
    //******************** Machine Station
    String machineRxBuffer;
    if (Comm.rxData(machineRxBuffer)) {
      String reply = "from machine to rc ";  //checkRxStr(machineRxBuffer);
#ifdef VERBOSE
      Serial.println(machineRxBuffer + "\n as received on machine");
      Serial.println(reply + " as transmitted from machine");
#endif
      Comm.txData(reply);
    }
  }
  timing = millis();
  digitalWrite(LED_BUILTIN, true);
}

内容的提问来源于stack exchange，提问作者user1511360