How can I fix this strange rollback?

Using Arduino Displays
1

I had programming to use LiquidCrystal_I2C, and integrated find I2C address and use LCD. So I use class, but it has something wrong. I made just one object, but the program loop back a specific part

Here is my code

//main.ino
#include "LCD.h"

LCD_CUSTOM LCD;

void setup() {
  
}

void loop() {
  // put your main code here, to run repeatedly:

}

//LCD.h
#ifndef LCDLibrary_H
#define LCDLibrary_H

#include "Arduino.h"
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

class LCD_CUSTOM {
  public: 
    uint8_t address;
    LCD_CUSTOM() {
      Serial.begin(9600);
      address = 0;
      init();
      running();
    };
  private:
    void init();
    void running();

};

#endif

// LCD.cpp
#include "LCD.h"

void LCD_CUSTOM::init() {
  Wire.begin();

  Serial.println("\n--------------------I2C Scanner--------------------");
  Serial.println(LCD_CUSTOM::address);

  byte error = 0;
  int nDevices;

  Serial.println("active");    // loop back point. 
  for(LCD_CUSTOM::address = 1; LCD_CUSTOM::address < 127; LCD_CUSTOM::address++) 
  {
    Wire.beginTransmission(LCD_CUSTOM::address);
    error = Wire.endTransmission();

    if(error == 0)
    {
      Serial.print("I2C device found at :address 0x");
      if(LCD_CUSTOM::address < 16) 
        Serial.println(" !");
      Serial.print(LCD_CUSTOM::address, HEX);
      Serial.println(" !");
      break;
    }

    else if(error==4) {
      Serial.print("Unknow error at address 0x");
      if(LCD_CUSTOM::address<16)
        Serial.print("0");
      Serial.println(LCD_CUSTOM::address, HEX);
    }
  }

  if(LCD_CUSTOM::address == 127)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");

  Serial.println("\n--------------------I2C Scanner End--------------------");
  Serial.println("Init complete. Running LCD");
}

void LCD_CUSTOM::running() {
  LiquidCrystal_I2C lcd(address, 16, 2);
  lcd.begin();
  lcd.print("Hello, World!");
}
2

Make the following changes:

void setup() {
  LCD.init();
}


void LCD_CUSTOM::running() {
  LiquidCrystal_I2C lcd(LCD_CUSTOM::address, 16, 2); // Use LCD_CUSTOM::address
  lcd.begin();
  lcd.print("Hello, World!");
}


// LCD.h
#ifndef LCDLibrary_H
#define LCDLibrary_H

#include "Arduino.h"
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

class LCD_CUSTOM {
  public: 
    uint8_t address;
    LCD_CUSTOM();
    void init();
    void running();
};

#endif

// LCD.cpp
#include "LCD.h"

LCD_CUSTOM::LCD_CUSTOM() {
  Serial.begin(9600);
  address = 0;
}

void LCD_CUSTOM::init() {
  Wire.begin();

  Serial.println("\n--------------------I2C Scanner--------------------");
  Serial.println(address);

  byte error = 0;
  int nDevices;

  Serial.println("active");
  for(address = 1; address < 127; address++) {
    Wire.beginTransmission(address);
    error = Wire.endTransmission();

    if (error == 0) {
      Serial.print("I2C device found at address 0x");
      if (address < 16) 
        Serial.print("0");
      Serial.println(address, HEX);
      break;
    } else if (error == 4) {
      Serial.print("Unknown error at address 0x");
      if (address < 16)
        Serial.print("0");
      Serial.println(address, HEX);
    }
  }

  if (address == 127)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");

  Serial.println("\n--------------------I2C Scanner End--------------------");
  Serial.println("Init complete. Running LCD");
}

void LCD_CUSTOM::running() {
  LiquidCrystal_I2C lcd(address, 16, 2);
  lcd.begin();
  lcd.print("Hello, World!");
}


#include "LCD.h"

LCD_CUSTOM LCD;

void setup() {
  LCD.init();
}

void loop() {
  LCD.running();
}
1 Like
3

It works! Thank you so much.

But why did this happen?

4

Your loop was void. And also you did not initialize the LCD in your setup function. These were the main issues.

1 Like
5

I see. Thank you for reply!

6

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