LCD 20x4 on Megatronics v3 with Marlin

Greetings,

I have a 20x4 LCD for use with the Megatronics v3.

I've tried following the tutorial but I'm no being able to properly configure the display. All I get at most is two lines of solid squares when I mess around with the trimpot on the board. I do get a few characters on the bottom line

Right now the only LCD configuration lines I have in the firmware are the following in the main.ino file:

#ifdef ULTRA_LCD
  #if defined(LCD_I2C_TYPE_PCF8575)
    #include 
    #include 
  #elif defined(LCD_I2C_TYPE_MCP23017) || defined(LCD_I2C_TYPE_MCP23008)
    #include 
    #include 
  #elif defined(DOGLCD)
    #include  // library for graphics LCD by Oli Kraus (https://code.google.com/p/u8glib/)
  #else
    #include  // library for character LCD
  #endif
#endif

I've also tried adding it like so:

#ifdef ULTRA_LCD
   #define LCD_WIDTH 20
   #define LCD_HEIGHT 4
// #endif
//
//#ifdef ULTRA_LCD
  #if defined(LCD_I2C_TYPE_PCF8575)
    #include 
    #include 
  #elif defined(LCD_I2C_TYPE_MCP23017) || defined(LCD_I2C_TYPE_MCP23008)
    #include 
    #include 
  #elif defined(DOGLCD)
    #include  // library for graphics LCD by Oli Kraus (https://code.google.com/p/u8glib/)
  #else
    #include  // library for character LCD
  #endif
#endif

Am I over defining the LCD settings?

Any help is appreciated.

Is there really no one who can help?

Are you running the Release Candidate? Specifically, RCBugFix? That is your best bet. This has changed depending upon the version you are running.

I think you want to make sure you have:

#define LANGUAGE_INCLUDE GENERATE_LANGUAGE_INCLUDE(en)
#define DISPLAY_CHARSET_HD44780_JAPAN // this is the most common hardware
#define ULTRA_LCD //general LCD support, also 16x

setup in your Configuration.h

Yeah, those are all included in the configuration.h file

What I don't know is where to configure it for the 20x4 LCD I have. All I get out of the display are two lines of solid squares, with some characters visible when I press one of the buttons on the keypad. Sometimes I'm not sure I'm actually turning the contrast trimpot on the board, but regardless of that I should be getting all 4 lines of the display, not just two.

I'm at my wits end with this thing.

I did find the LCD size lines in the "Conditionals.H" file but I don't understand why I keep getting only two lines and, when I do get the contrast settings right, I get some odd random characters on one of the lines. If I move the trimpot at most I'll get the first and third line all solid squares.

Is it possible that my LCD is incorrectly assembled (I bought it fully assembled from the store)?

I think it is more likely that you have the wrong display type configured. There are a lot of people at github.com/MarlinFirmware/Marlin that do work involving the LCD Panels. It might be worth while starting a thread there and asking. I suspect you will get an answer very quickly and it will be correct.