NodeMCU串口通信触发Exception(9)，求ADC数据解析与网页展示修复方案

我有一套UI与主板设备，二者通过UART协议通信。已为主板添加基础代码，使其发送格式为ADC1=xxxx ADC2=yyyy的数据。希望仅从主板捕获该格式数据，提取其中的xxxx与yyyy（整数或字符串），并通过NodeMCU将其展示在基础HTML页面中。但运行代码后出现Exception(9)错误，推测可能原因：

• 串口端口写入的数据量过大，导致系统崩溃
• 代码本身存在问题

#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>

int incomingByte = 0;
char deneme[] = "";
const char *delp;
const char *delp2;
/*Put your SSID & Password*/
const char* ssid = "ssid";  // Enter SSID here
const char* password = "pass";  //Enter Password here
ESP8266WebServer server(80);
float Temperature;
float Humidity;
 
void setup() {
  Serial.begin(9600);
  delay(100);
  Serial.println("Connecting to ");
  Serial.println(ssid);

  //connect to your local wi-fi network
  WiFi.begin(ssid, password);

  //check wi-fi is connected to wi-fi network
  while (WiFi.status() != WL_CONNECTED) {
  delay(1000);
  Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected..!");
  Serial.print("Got IP: ");  Serial.println(WiFi.localIP());

  server.on("/", handle_OnConnect);
  server.onNotFound(handle_NotFound);

  server.begin();
  Serial.println("HTTP server started");

}
void loop() {

  if (Serial.available()) // now we have at least one character in the Serial input buffer
  {

String incomingStr = Serial.readStringUntil('\n');
incomingStr.toCharArray(deneme,32);
 Serial.println(deneme);
 delp = strtok (deneme,"-");
 delp2 = strtok (NULL,"-");
 Serial.println(delp);
 Serial.println(delp2);

 }
server.handleClient();
 
delay(500);

}

void handle_OnConnect() {
  server.send(200, "text/html", SendHTML(Temperature,Humidity)); 
}

void handle_NotFound(){
  server.send(404, "text/plain", "Not found");
}

String SendHTML(float Temperaturestat,float Humiditystat){
  String ptr = "<!DOCTYPE html> <html>\n";
  ptr +="<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0, user-scalable=no\">\n";
  ptr +="<title>ESP8266 Weather Report</title>\n";
  ptr +="<style>html { font-family: Helvetica; display: inline-block; margin: 0px auto; text-align: center;}\n";
  ptr +="body{margin-top: 50px;} h1 {color: #444444;margin: 50px auto 30px;}\n";
  ptr +="p {font-size: 24px;color: #444444;margin-bottom: 10px;}\n";
  ptr +="</style>\n";
  ptr +="<script>\n"; 
  ptr +="setInterval(loadDoc,200);\n";
  ptr +="function loadDoc() {\n";
  ptr +="var xhttp = new XMLHttpRequest();\n";
  ptr +="xhttp.onreadystatechange = function() {\n";
  ptr +="if (this.readyState == 4 && this.status == 200) {\n";
  ptr +="document.getElementById(\"webpage\").innerHTML =this.responseText}\n";
  ptr +="};\n";
  ptr +="xhttp.open(\"GET\", \"/\", true);\n";
  ptr +="xhttp.send();\n";
  ptr +="}\n";
  ptr +="</script>\n";
  ptr +="</head>\n";
  ptr +="<body>\n";
  ptr +="<div id=\"webpage\">\n";
  ptr +="<h1>ESP8266 NodeMCU Weather Report</h1>\n";
  
  ptr +="<p>Temperature: ";
  ptr +=delp;
  ptr += " NTC</p>";
  ptr +="<p>Humidity: ";
  ptr +=delp2;
  ptr += " Heatsink</p>";
  
  ptr +="</div>\n";
  ptr +="</body>\n";
  ptr +="</html>\n";
  return ptr;
}

Exception(9)是ESP8266的内存访问越界/栈溢出错误，核心问题集中在内存管理和字符串解析逻辑：

1. 数组越界：char deneme[] = "";定义的是长度仅为1的字符数组，调用incomingStr.toCharArray(deneme,32);时会向超出数组范围的内存写入数据，直接破坏ESP8266内存结构，引发崩溃。
2. 解析逻辑错误：使用strtok(deneme,"-")分割字符串，但主板发送格式的分隔符是空格和=，用-分割完全无法提取目标数据，同时导致delp/delp2成为野指针，生成HTML时访问非法内存。
3. 刷新频率过高：setInterval(loadDoc,200)设置200ms一次HTTP请求，给ESP8266带来过大处理压力，加重内存问题。
4. 全局指针风险：delp和delp2是全局指针，指向的内存（deneme）被覆盖或越界后变为无效指针，访问时触发错误。

关键改动点 #

• 扩大deneme数组容量，避免越界
• 重写字符串解析逻辑，正确提取ADC1和ADC2的值
• 使用全局变量存储解析后的数值，替代风险指针
• 降低页面刷新频率，减轻ESP8266负载
• 增加数据合法性校验，避免解析错误数据

修正后代码 #

#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>

/*Put your SSID & Password*/
const char* ssid = "ssid";  
const char* password = "pass";  

ESP8266WebServer server(80);
// 用全局变量存储解析后的ADC值
String adc1Value = "0";
String adc2Value = "0";
 
void setup() {
  Serial.begin(9600);
  delay(100);
  Serial.println("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected..!");
  Serial.print("Got IP: ");  
  Serial.println(WiFi.localIP());

  server.on("/", handle_OnConnect);
  server.onNotFound(handle_NotFound);
  server.begin();
  Serial.println("HTTP server started");
}

void loop() {
  if (Serial.available()) {
    String incomingStr = Serial.readStringUntil('\n');
    // 去掉字符串首尾的空白字符（包括换行、空格）
    incomingStr.trim();
    
    // 校验数据格式是否符合要求
    if (incomingStr.startsWith("ADC1=") && incomingStr.indexOf("ADC2=") != -1) {
      // 按空格分割成两部分
      int spaceIndex = incomingStr.indexOf(' ');
      if (spaceIndex != -1) {
        String adc1Part = incomingStr.substring(0, spaceIndex);
        String adc2Part = incomingStr.substring(spaceIndex + 1);
        
        // 提取ADC1的值（=后面的部分）
        int eqIndex1 = adc1Part.indexOf('=');
        if (eqIndex1 != -1) {
          adc1Value = adc1Part.substring(eqIndex1 + 1);
        }
        
        // 提取ADC2的值
        int eqIndex2 = adc2Part.indexOf('=');
        if (eqIndex2 != -1) {
          adc2Value = adc2Part.substring(eqIndex2 + 1);
        }
        
        Serial.print("Parsed - ADC1: ");
        Serial.print(adc1Value);
        Serial.print(" | ADC2: ");
        Serial.println(adc2Value);
      }
    } else {
      // 格式不符合时打印日志，跳过解析
      Serial.println("Invalid data format: " + incomingStr);
    }
  }
  
  server.handleClient();
  // 移除不必要的delay，避免影响HTTP请求处理
}

void handle_OnConnect() {
  server.send(200, "text/html", SendHTML()); 
}

void handle_NotFound(){
  server.send(404, "text/plain", "Not found");
}

String SendHTML(){
  String ptr = "<!DOCTYPE html> <html>\n";
  ptr += "<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0, user-scalable=no\">\n";
  ptr += "<title>ADC Data Display</title>\n";
  ptr += "<style>html { font-family: Helvetica; display: inline-block; margin: 0px auto; text-align: center;}\n";
  ptr += "body{margin-top: 50px;} h1 {color: #444444;margin: 50px auto 30px;}\n";
  ptr += "p {font-size: 24px;color: #444444;margin-bottom: 10px;}\n";
  ptr += "</style>\n";
  ptr += "<script>\n"; 
  // 调整刷新间隔为2秒，减轻ESP8266负载
  ptr += "setInterval(loadDoc, 2000);\n";
  ptr += "function loadDoc() {\n";
  ptr += "var xhttp = new XMLHttpRequest();\n";
  ptr += "xhttp.onreadystatechange = function() {\n";
  ptr += "if (this.readyState == 4 && this.status == 200) {\n";
  ptr += "document.getElementById(\"webpage\").innerHTML = this.responseText;\n";
  ptr += "}\n";
  ptr += "};\n";
  ptr += "xhttp.open(\"GET\", \"/\", true);\n";
  ptr += "xhttp.send();\n";
  ptr += "}\n";
  ptr += "</script>\n";
  ptr += "</head>\n";
  ptr += "<body>\n";
  ptr += "<div id=\"webpage\">\n";
  ptr += "<h1>NodeMCU ADC Data Display</h1>\n";
  
  ptr += "<p>ADC1 Value: ";
  ptr += adc1Value;
  ptr += "</p>";
  ptr += "<p>ADC2 Value: ";
  ptr += adc2Value;
  ptr += "</p>";
  
  ptr += "</div>\n";
  ptr += "</body>\n";
  ptr += "</html>\n";
  return ptr;
}

额外优化建议 #

• 如果需要数值计算，可将adc1Value和adc2Value转为int或float类型存储
• 若串口数据发送频繁，可增加串口缓冲区处理逻辑，避免数据丢失
• 可为HTML页面添加简单样式优化，提升显示效果

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