从SIM900模块ESP32解析串行数据

Question

所以最近我一直在考虑让我自己的手机没什么特别的，只是一个带有触摸屏和基本功能的基本手机，呼叫消息日历联系人列表以及连接到互联网并通过 API 调用提供天气信息的能力。 。 我用于 gsm 和 GPRS 通信的模块是流行的 sim900 模块。我可以沟通 我可以打电话 我可以做任何事情。但是陷入了一个可能（如果不是不可能克服）困难的障碍。您会看到 sim900 模块在收到呼叫时通过串行端口传输“RING”命令，然后是“+CLIP....（来电显示内容） ”。好的，我收到了，我正在分解它并接受命令，一切正常。但情况来了..我想读取剩余的电池容量（AT + CBC）和GSM信号强度（AT + CSQ）都很好我以固定的间隔（例如3秒）发送这2个命令电池信号10。但现在，当有电话打来时，它可能与尝试读取电池的传入响应重叠。假设我询问模块电池电量是多少。然后模块将通过发送“+CBC：（和电池电量）”进行响应，然后假设在同一时间我接到电话。然后串行端口上的所有数据都变得混乱并且没有任何工作。我的代码非常粗糙，而且解析部分肯定很糟糕，但我更担心解析不是问题。问题是传入数据冲突。有什么方法可以解决这个问题吗？或者有其他关于在哪里寻找以及如何解决问题的建议吗？ 来自 gsm 的每个命令都由 0D0A 序列（CRLF）分隔，

下面是我正在做的示例代码

//for parsing
String incomStr;
String FirstStr;
String SecondStr;
String ThirdStr;
String FourthStr;
String FifthStr;
String SixthStr;
int strcount;
char incomChar;
boolean flagz = false;


//parsing
void getIncomingCommand() {
  if (Gsm.available()) {
    incomChar = Gsm.read();
    //check to see if 0D0A if yes split the string 
    if ((incomChar == 0x0D) | flagz) {
      flagz = true;
      if (incomChar == 0x0A) {
        switch (strcount) {
          case 0:
            FirstStr = incomStr;
            incomStr = "";
            strcount++;
            flagz = false;
            break;
          case 1:
            SecondStr = incomStr;
            incomStr = "";
            strcount++;
            flagz = false;
            break;
          case 2:
            ThirdStr = incomStr;
            incomStr = "";
            strcount++;
            flagz = false;
            break;
          case 3:
            FourthStr = incomStr;
            incomStr = "";
            strcount++;
            flagz = false;
            break;
          case 4:
            FifthStr = incomStr;
            incomStr = "";
            strcount++;
            flagz = false;
            break;
          case 5:
            SixthStr = incomStr;
            incomStr = "";
            strcount++;
            flagz = false;
            break;
          default:
            strcount++;
            flagz = false;
            incomStr = "";
        }
      }
    } else {
      incomStr += incomChar;
    }
  }
}


void clearIncomingCommand() {
  FirstStr = "";
  SecondStr = "";
  ThirdStr = "";
  FourthStr = "";
  FifthStr = "";
  SixthStr = "";
  strcount = 0;
}


int getSignalLvl() {
  char tempchar;
  String tempstr;
  Gsm.print("AT+CSQ");
  Gsm.write(0x0D);
  Gsm.write(0x0A);
  delay(180);
  while (Gsm.available()) {
    tempchar = Gsm.read();
    tempstr += tempchar;
  }
  return tempstr.substring(16, tempstr.indexOf(",")).toInt();
}

String getTime() {
  char tempchar;
  String tempstr;
  Gsm.print("AT+CCLK?");
  Gsm.write(0x0D);
  Gsm.write(0x0A);
  delay(180);
  while (Gsm.available()) {
    tempchar = Gsm.read();
    tempstr += tempchar;
  }
  return tempstr.substring(tempstr.indexOf(",") + 1, tempstr.lastIndexOf(":"));
}

void setup() {
  //start serial port
  Serial.begin(115200);
  //start the gsm port
  Gsm.begin(9600, SERIAL_8N1, 32, 33);
  strcount = 0;
  updateTime(getTime());
  delay(200);
  updateSignal(getSignalLvl());
}

void loop() {
  //stuff inside here will only be called / run only every X amount of time
  // X = SECONDS/1000;
  if ((millis() - lastupdate) >= 60000) {
    updateTime(getTime());
    lastupdate = millis();
  }



  getIncomingCommand();
  if (SecondStr == "RING" & FourthStr.substring(0, 5) == "+CLIP") {
    Serial.print("SomeOne is calling!! Number: ");
    Serial.println(FourthStr.substring(8, 21));
      Serial.println(phoneNums[i]);
      Serial.println(FourthStr.substring(8, 21));
      callerPhone = FourthStr.substring(8, 21);
      clearIncomingCommand();
    //important change state only once!
    if (!change_state) {
      came_from = state ;
      change_state = 1;
    }
    Serial.print("coming from: ");
    Serial.println(came_from);
    state = 4;
    flag = 0;
  }
  else if (SecondStr == "NO CARRIER") {
    Serial.println("CALL ENDED");
    clearIncomingCommand();
    if (state == 3) {
      state = 5;
      flag = 0;
    } else if (state == 4) {
      state = came_from;
      flag = 0;
    }
    change_state = 0;
  }
  else if (SecondStr == "MO RING") {
    Serial.println("CALLING...");
    clearIncomingCommand();

  }
  else if (SecondStr == "MO CONNECTED") {
    Serial.println("CALL CONNECTED");
    clearIncomingCommand();
    if (state == 2) {
      state = 3;
      flag = 0;
    }
  } else if (FourthStr == "OK" | ThirdStr == "OK") {
    Serial.println("Recieved ok clearing buffers");
    clearIncomingCommand();

  }


}