File content as of revision 3:bc884631d057:

/*************************************************** 
  This is a library for the Adafruit RGB 16x2 LCD Shield 
  Pick one up at the Adafruit shop!
  ---------> http://http://www.adafruit.com/products/714

  The shield uses I2C to communicate, 2 pins are required to  
  interface
  Adafruit invests time and resources providing this open source code, 
  please support Adafruit and open-source hardware by purchasing 
  products from Adafruit!

  Written by Limor Fried/Ladyada for Adafruit Industries.  
  BSD license, all text above must be included in any redistribution
 ****************************************************/

#ifndef Adafruit_RGBLCDShield_h
#define Adafruit_RGBLCDShield_h

#include <inttypes.h>
#include <MCP23017.h>

// commands
#define LCD_CLEARDISPLAY 0x01
#define LCD_RETURNHOME 0x02
#define LCD_ENTRYMODESET 0x04
#define LCD_DISPLAYCONTROL 0x08
#define LCD_CURSORSHIFT 0x10
#define LCD_FUNCTIONSET 0x20
#define LCD_SETCGRAMADDR 0x40
#define LCD_SETDDRAMADDR 0x80

// flags for display entry mode
#define LCD_ENTRYRIGHT 0x00
#define LCD_ENTRYLEFT 0x02
#define LCD_ENTRYSHIFTINCREMENT 0x01
#define LCD_ENTRYSHIFTDECREMENT 0x00

// flags for display on/off control
#define LCD_DISPLAYON 0x04
#define LCD_DISPLAYOFF 0x00
#define LCD_CURSORON 0x02
#define LCD_CURSOROFF 0x00
#define LCD_BLINKON 0x01
#define LCD_BLINKOFF 0x00

// flags for display/cursor shift
#define LCD_DISPLAYMOVE 0x08
#define LCD_CURSORMOVE 0x00
#define LCD_MOVERIGHT 0x04
#define LCD_MOVELEFT 0x00

// flags for function set
#define LCD_8BITMODE 0x10
#define LCD_4BITMODE 0x00
#define LCD_2LINE 0x08
#define LCD_1LINE 0x00
#define LCD_5x10DOTS 0x04
#define LCD_5x8DOTS 0x00

#define BUTTON_UP 0x08
#define BUTTON_DOWN 0x04
#define BUTTON_LEFT 0x10
#define BUTTON_RIGHT 0x02
#define BUTTON_SELECT 0x01

class Adafruit_RGBLCDShield
    : public Serial // MBED was Print
{
public:
    // Updated constructor
  Adafruit_RGBLCDShield(MCP23017 & inMCP);
  Adafruit_RGBLCDShield
  (
    MCP23017 &  inMCP,
    uint8_t     inRs,
    uint8_t     inRw,
    uint8_t     inEn,
    uint8_t     inD4,
    uint8_t     inD5,
    uint8_t     inD6,
    uint8_t     inD7
  );


  void init(uint8_t fourbitmode, uint8_t rs, uint8_t rw, uint8_t enable,
        uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
        uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7);
    
  void begin(uint8_t cols, uint8_t rows, uint8_t charsize = LCD_5x8DOTS);
  uint8_t lines();

  void clear();
  void home();

  void noDisplay();
  void display();
  void noBlink();
  void blink();
  void noCursor();
  void cursor();
  void scrollDisplayLeft();
  void scrollDisplayRight();
  void leftToRight();
  void rightToLeft();
  void autoscroll();
  void noAutoscroll();
  
  // only if using backpack
  void setBacklight(uint8_t status); 

  void createChar(uint8_t, uint8_t[]);
  void setCursor(uint8_t, uint8_t); 
#if ARDUINO >= 100
  //virtual size_t write(uint8_t);
#else
  //virtual void write(uint8_t);
  virtual int _putc(int c);
#endif
  void command(uint8_t);
  uint8_t readButtons();

private:
  void send(uint8_t, uint8_t);
  void write4bits(uint8_t);
  void write8bits(uint8_t);
  void pulseEnable();
  void _digitalWrite(uint8_t, uint8_t);
  void _pinMode(uint8_t, uint8_t);

  uint8_t _rs_pin; // LOW: command.  HIGH: character.
  uint8_t _rw_pin; // LOW: write to LCD.  HIGH: read from LCD.
  uint8_t _enable_pin; // activated by a HIGH pulse.
  uint8_t _data_pins[8];
  uint8_t _button_pins[5];
  uint8_t _displayfunction;
  uint8_t _displaycontrol;
  uint8_t _displaymode;

  uint8_t _initialized;

  uint8_t _numlines,_currline;

  uint8_t _i2cAddr;
  MCP23017 _i2c;
};

#endif