CODEWITHSUNDEEP
arduinoesp32arduino-idearduino-esp32
Panos Fusu
Panos Fusu

Reputation: 21

ESP32 Board reboots non-stop

I'm trying to upload a script to my ESP32 DOIT board through Arduino IDE. tl;dr: I'm trying to get a string from a webform and print it on a 0.96" OLED display.

The code I'm using is a combination of two scripts: the first one was a tutorial about hosting a webserver with input html forms in an ESP32 and the second was the OLED SSD1306 example from the Adafruit Library.

The final code I'm using is:

#include <Arduino.h>
#include <WiFi.h>
#include <AsyncTCP.h>
#include <ESPAsyncWebServer.h>
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 32 // OLED display height, in pixels
#define OLED_RESET     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

AsyncWebServer server(80);

// I REPLACED WITH MY NETWORK CREDENTIALS
const char* ssid = "my_ssid";
const char* password = "mypassword";

const char* PARAM_INPUT_1 = "input1";

// HTML web page to handle 3 input fields (input1, input2, input3)
const char index_html[] PROGMEM = R"rawliteral(
<!DOCTYPE HTML><html><head>
  <title>ESP Input Form</title>
  <meta name="viewport" content="width=device-width, initial-scale=1">
  </head><body>
  <form action="/get">
    input1: <input type="text" name="input1">
    <input type="submit" value="Submit">
  </form><br>
</body></html>)rawliteral";

void notFound(AsyncWebServerRequest *request) {
  request->send(404, "text/plain", "Not found");
}

void setup() {
  Serial.begin(115200);
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  if (WiFi.waitForConnectResult() != WL_CONNECTED) {
    Serial.println("WiFi Failed!");
    return;
  }
  Serial.println();
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP());

  // Send web page with input fields to client
  server.on("/", HTTP_GET, [](AsyncWebServerRequest *request){
    request->send_P(200, "text/html", index_html);
  });

  // Send a GET request to <ESP_IP>/get?input1=<inputMessage>
  server.on("/get", HTTP_GET, [] (AsyncWebServerRequest *request) {
    String inputMessage;
    String inputParam;
    // GET input1 value on <ESP_IP>/get?input1=<inputMessage>
    if (request->hasParam(PARAM_INPUT_1)) {
      inputMessage = request->getParam(PARAM_INPUT_1)->value();
      inputParam = PARAM_INPUT_1;
    }
    else {
      inputMessage = "No message sent";
      inputParam = "none";
    }
    Serial.println(inputMessage);
    request->send(200, "text/html", "HTTP GET request sent to your ESP on input field (" 
                                     + inputParam + ") with value: " + inputMessage +
                                     "<br><a href=\"/\">Return to Home Page</a>");

    delay(2000);
    display.clearDisplay();

    display.setTextSize(5);
    display.setTextColor(WHITE);
    display.setCursor(0, 10);

    display.println(inputMessage);
    display.display();
    delay(5000);
    display.clearDisplay();
    display.display();                                 
  });
  server.onNotFound(notFound);
  server.begin();
}

void loop() {
  
}

The code uploads just fine, but in Serial Monitor I get the message:

Guru Meditation Error: Core  1 panic'ed (LoadProhibited). Exception was unhandled.

Core  1 register dump:
PC      : 0x400dafd2  PS      : 0x00060d30  A0      : 0x800d2add  A1      : 0x3ffb27a0  
A2      : 0x3ffc2d6c  A3      : 0x000001ff  A4      : 0x00000000  A5      : 0x00000001  
A6      : 0x0000ffff  A7      : 0x0000007f  A8      : 0x800daf9f  A9      : 0x3ffb2780  
A10     : 0x3ffc2f10  A11     : 0x00000040  A12     : 0x4014bb80  A13     : 0x00000006  
A14     : 0x000000ff  A15     : 0x4014bb80  SAR     : 0x0000000a  EXCCAUSE: 0x0000001c  
EXCVADDR: 0x00000000  LBEG    : 0x40089a95  LEND    : 0x40089aa5  LCOUNT  : 0xfffffffe  


Backtrace:0x400dafcf:0x3ffb27a00x400d2ada:0x3ffb27d0 0x400dd3b2:0x3ffb2820 

ELF file SHA256: 0000000000000000

Rebooting...

I tried 3 of my ESP32 boards and everytime I get the same message. When I remove the part where I print my string on the display, there's (obviously) no error.

Can you please point out how to overcome this problem? Why using each part of my code seperately works, but combining them doesn't work?

Thank you in advance!

Upvotes: 1

Views: 1001

Answers (2)

Panos Fusu
Panos Fusu

Reputation: 21

It seems that this famous project does exactly what I was trying to do and it works like a charm.

Upvotes: -1

romkey
romkey

Reputation: 7044

Your code is using ESPAsyncWebServer.

Your callback for "/get" calls delay(). This is explicitly forbidden in the ESPAsyncWebServer README:

You can not use yield or delay or any function that uses them inside the callbacks

Your callback also does quite a bit of computation, calling 3rd party libraries that you can't be sure are safe to call here.

You need to rewrite the callback. Instead of doing work there, save the message you want to display in a variable and set a boolean variable indicating there's work to be done. Then in loop(), when the boolean is true, do the work that the callback did and clear the flag indicating there was work to be done.

For instance, your new code might look something like this:

boolean show_message = false;
String input_message;

void setup() {
  ...

  server.on("/get", HTTP_GET, [] (AsyncWebServerRequest *request) {
    String inputParam;
    // GET input1 value on <ESP_IP>/get?input1=<inputMessage>
    if (request->hasParam(PARAM_INPUT_1)) {
      inputMessage = request->getParam(PARAM_INPUT_1)->value();
      inputParam = PARAM_INPUT_1;
    }
    else {
      inputMessage = "No message sent";
      inputParam = "none";
    }
    Serial.println(inputMessage);
    request->send(200, "text/html", "HTTP GET request sent to your ESP on input field (" 
                                     + inputParam + ") with value: " + inputMessage +
                                     "<br><a href=\"/\">Return to Home Page</a>");
    show_message = true;
    }

    ...
}

void loop() {
  if(show_message) {
    // code to do the work goes here

    show_message = false;
  }
}

Upvotes: 2

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