Library for lcd I2C display (Matrix Orbital LK404-25)

Projects Programming
1

Hi all,

I have a Matrix Orbital 4x40 lcd I2C display, LK404-25 / VK404-25 version

Looking for a proper library, the best I found is "LCDi2c-LK162-12" library from Arduino Playground - HomePage

When I try to compile this simple code

#include <LCDI2C_LK162-12.h>

LCDI2C lcd = LCDI2C(4,40,0x50,0);

void setup(){
  lcd.init();
  lcd.setCursor(0,0);
  lcd.print("Hello");
}

void loop(){

}

I have the following internal library error:

LCDI2C_LK162-12.h:38: error: conflicting return type specified for ‘virtual void LCDI2C::write(uint8_t)’
Print.h:48: error: overriding ‘virtual size_t Print::write(uint8_t)’

Here is the library .h and .cpp files

LCDI2C_LK162-12.h

#ifndef LCDI2Ct_h

#define LCDI2C_h

#define CMDDELAY 50        // Delay to wait after sending commands;
#define POSDELAY 100		 // Long delay required by Position command
#define CHARDELAY 0



#define LCDI2C_MIN_BRIGHTNESS		0
#define LCDI2C_MAX_BRIGHTNESS		250
#define LCDI2C_VALUE_OUT_OF_RANGE	1
#define LCDI2C_MIN_CONTRAST			0
#define LCDI2C_MAX_CONTRAST			100




#include <inttypes.h>
#include "Print.h"



class LCDI2C : public Print {

public: 

//LCDI2C(int num_lines,int num_col,int i2c_address,int display);
	
LCDI2C(int,int,int,int);
  
	void command(int value);
	void writeStartUpScreen(char message[32]);

  void init();
	
  virtual void write(uint8_t);

  void clear();
  
  void home();
  
  void on(int value);
  
  void off();
  
  void cursor_on();
  
  void cursor_off();
  
  void blink_on();
  
  void blink_off();
  
  void left();
  
  void right();
  
  int keypad();
 
  	// Overload the Print class function for strings because
	// the base class implementation causes problems by doing
	// an I2C I/O for every character
  void printstr(const char[]);
	
  void setCursor(int line_num, int x);

// Values for graphtype in calls to init_bargraph
#define LCDI2C_THIN_VERTICAL_BAR_GRAPH    1 // **
#define LCDI2C_THICK_VERTICAL_BAR_GRAPH    2 // **
#define LCDI2C_HORIZONTAL_BAR_GRAPH  3
#define LCDI2C_HORIZONTAL_LINE_GRAPH 4

  unsigned char init_bargraph(unsigned char graphtype);
  void draw_horizontal_graph(unsigned char row, unsigned char column, unsigned char len,  unsigned char pixel_col_end);
  void draw_vertical_graph(unsigned char row, unsigned char column, unsigned char len,  unsigned char pixel_col_end);

#define LCDI2C_NUM_CUSTOM_CHARS 8
#define LCDI2C_CUSTOM_CHAR_SIZE 8
  void load_custom_character(unsigned char char_num, unsigned char *rows);
  unsigned char set_backlight_brightness(unsigned char new_val);
  unsigned char set_contrast(unsigned char new_val);
 
private:

};
#endif

LCDI2C_LK162-12.cpp only involved part

void LCDI2C::write(uint8_t value) {
	
	Wire.beginTransmission(g_i2caddress);
	Wire.send(value);
	Wire.endTransmission();
	delay(5);
}

Is this library wrong? Someone knows a solution to tix this, or another library to use a standard lcd display connected by I2C?

2

The message is telling you that the write() method in that class is incorrect. It is telling you that the return type, void, is wrong, and should be size_t.

Both the header file and source file need to be changed. Don't forget to add the required return statement (returning the number of bytes printed/written).