Bdubs modified i2c LCD backpack library for Spark Core, adapted for the Adafruit RGB LCD shield by gin

adafruit_rgb_lcd_sparkcore

//-----------------------------------------------//
// I2C / SPI LCD BACKPACK LIBRARY FOR SPARK CORE //
//===============================================//
// Copy this into a new application at:          //
// https://www.spark.io/build and go nuts!       //
// !! Pinouts on line 427 below !!               //
//-----------------------------------------------//
// Technobly / BDub - Jan 16th 2014              //
//===============================================//
 
/* ===================== Adafruit_MCP23017.h ========================= */

#define _BV(bit) (1 << (bit)) // used in LiquidCrystal.cpp

/*************************************************** 
  This is a library for the MCP23017 i2c port expander

  These displays use 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
 ****************************************************/

// Don't forget the Wire library
class Adafruit_MCP23017 {
public:
  void begin(uint8_t addr);
  void begin(void);

  void pinMode(uint8_t p, uint8_t d);
  void digitalWrite(uint8_t p, uint8_t d);
  void pullUp(uint8_t p, uint8_t d);
  uint8_t digitalRead(uint8_t p);

  void writeGPIOAB(uint16_t);
  uint16_t readGPIOAB();

 private:
  uint8_t i2caddr;
};

#define MCP23017_ADDRESS 0x20

// registers
#define MCP23017_IODIRA 0x00
#define MCP23017_IPOLA 0x02
#define MCP23017_GPINTENA 0x04
#define MCP23017_DEFVALA 0x06
#define MCP23017_INTCONA 0x08
#define MCP23017_IOCONA 0x0A
#define MCP23017_GPPUA 0x0C
#define MCP23017_INTFA 0x0E
#define MCP23017_INTCAPA 0x10
#define MCP23017_GPIOA 0x12
#define MCP23017_OLATA 0x14


#define MCP23017_IODIRB 0x01
#define MCP23017_IPOLB 0x03
#define MCP23017_GPINTENB 0x05
#define MCP23017_DEFVALB 0x07
#define MCP23017_INTCONB 0x09
#define MCP23017_IOCONB 0x0B
#define MCP23017_GPPUB 0x0D
#define MCP23017_INTFB 0x0F
#define MCP23017_INTCAPB 0x11
#define MCP23017_GPIOB 0x13
#define MCP23017_OLATB 0x15

/* ===================== Adafruit_MCP23017.cpp ========================= */
/*************************************************** 
  This is a library for the MCP23017 i2c port expander

  These displays use 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
 ****************************************************/

//#include <Wire.h>
//#include <avr/pgmspace.h>
//#include "Adafruit_MCP23017.h"

 #define WIRE Wire

// minihelper
static inline void wiresend(uint8_t x) {

  WIRE.write((uint8_t)x);
  
}

static inline uint8_t wirerecv(void) {

  return WIRE.read();

}

////////////////////////////////////////////////////////////////////////////////

void Adafruit_MCP23017::begin(uint8_t addr) {
  if (addr > 7) {
    addr = 7;
  }
  i2caddr = addr;

  WIRE.begin();

  
  // set defaults!
  WIRE.beginTransmission(MCP23017_ADDRESS | i2caddr);
  wiresend(MCP23017_IODIRA);
  wiresend(0xFF);  // all inputs on port A
  WIRE.endTransmission();

  WIRE.beginTransmission(MCP23017_ADDRESS | i2caddr);
  wiresend(MCP23017_IODIRB);
  wiresend(0xFF);  // all inputs on port B
  WIRE.endTransmission();
}


void Adafruit_MCP23017::begin(void) {
  begin(0);
}

void Adafruit_MCP23017::pinMode(uint8_t p, uint8_t d) {
  uint8_t iodir;
  uint8_t iodiraddr;

  // only 16 bits!
  if (p > 15)
    return;

  if (p < 8)
    iodiraddr = MCP23017_IODIRA;
  else {
    iodiraddr = MCP23017_IODIRB;
    p -= 8;
  }

  // read the current IODIR
  WIRE.beginTransmission(MCP23017_ADDRESS | i2caddr);
  wiresend(iodiraddr);	
  WIRE.endTransmission();
  
  WIRE.requestFrom(MCP23017_ADDRESS | i2caddr, 1);
  iodir = wirerecv();

  // set the pin and direction
  if (d == INPUT) {
    iodir |= 1 << p; 
  } else {
    iodir &= ~(1 << p);
  }

  // write the new IODIR
  WIRE.beginTransmission(MCP23017_ADDRESS | i2caddr);
  wiresend(iodiraddr);
  wiresend(iodir);	
  WIRE.endTransmission();
}

uint16_t Adafruit_MCP23017::readGPIOAB() {
  uint16_t ba = 0;
  uint8_t a;

  // read the current GPIO output latches
  WIRE.beginTransmission(MCP23017_ADDRESS | i2caddr);
  wiresend(MCP23017_GPIOA);	
  WIRE.endTransmission();
  
  WIRE.requestFrom(MCP23017_ADDRESS | i2caddr, 2);
  a = wirerecv();
  ba = wirerecv();
  ba <<= 8;
  ba |= a;

  return ba;
}

void Adafruit_MCP23017::writeGPIOAB(uint16_t ba) {
  WIRE.beginTransmission(MCP23017_ADDRESS | i2caddr);
  wiresend(MCP23017_GPIOA);	
  wiresend(ba & 0xFF);
  wiresend(ba >> 8);
  WIRE.endTransmission();
}

void Adafruit_MCP23017::digitalWrite(uint8_t p, uint8_t d) {
  uint8_t gpio;
  uint8_t gpioaddr, olataddr;

  // only 16 bits!
  if (p > 15)
    return;

  if (p < 8) {
    olataddr = MCP23017_OLATA;
    gpioaddr = MCP23017_GPIOA;
  } else {
    olataddr = MCP23017_OLATB;
    gpioaddr = MCP23017_GPIOB;
    p -= 8;
  }

  // read the current GPIO output latches
  WIRE.beginTransmission(MCP23017_ADDRESS | i2caddr);
  wiresend(olataddr);	
  WIRE.endTransmission();
  
  WIRE.requestFrom(MCP23017_ADDRESS | i2caddr, 1);
   gpio = wirerecv();

  // set the pin and direction
  if (d == HIGH) {
    gpio |= 1 << p; 
  } else {
    gpio &= ~(1 << p);
  }

  // write the new GPIO
  WIRE.beginTransmission(MCP23017_ADDRESS | i2caddr);
  wiresend(gpioaddr);
  wiresend(gpio);	
  WIRE.endTransmission();
}

void Adafruit_MCP23017::pullUp(uint8_t p, uint8_t d) {
  uint8_t gppu;
  uint8_t gppuaddr;

  // only 16 bits!
  if (p > 15)
    return;

  if (p < 8)
    gppuaddr = MCP23017_GPPUA;
  else {
    gppuaddr = MCP23017_GPPUB;
    p -= 8;
  }


  // read the current pullup resistor set
  WIRE.beginTransmission(MCP23017_ADDRESS | i2caddr);
  wiresend(gppuaddr);	
  WIRE.endTransmission();
  
  WIRE.requestFrom(MCP23017_ADDRESS | i2caddr, 1);
  gppu = wirerecv();

  // set the pin and direction
  if (d == HIGH) {
    gppu |= 1 << p; 
  } else {
    gppu &= ~(1 << p);
  }

  // write the new GPIO
  WIRE.beginTransmission(MCP23017_ADDRESS | i2caddr);
  wiresend(gppuaddr);
  wiresend(gppu);	
  WIRE.endTransmission();
}

uint8_t Adafruit_MCP23017::digitalRead(uint8_t p) {
  uint8_t gpioaddr;

  // only 16 bits!
  if (p > 15)
    return 0;

  if (p < 8)
    gpioaddr = MCP23017_GPIOA;
  else {
    gpioaddr = MCP23017_GPIOB;
    p -= 8;
  }

  // read the current GPIO
  WIRE.beginTransmission(MCP23017_ADDRESS | i2caddr);
  wiresend(gpioaddr);	
  WIRE.endTransmission();
  
  WIRE.requestFrom(MCP23017_ADDRESS | i2caddr, 1);
  return (wirerecv() >> p) & 0x1;
}


//------------------------Adafruit_RGBLCDshield.h----------------------------------//

/*************************************************** 
  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
 ****************************************************/

//#include <inttypes.h>
//#include "Print.h"
//#include <Adafruit_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 Print {
public:
  Adafruit_RGBLCDShield();

  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);

  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); 

  virtual size_t write(uint8_t);

  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;
  Adafruit_MCP23017 _i2c;
};

//--------------------------------------Adafruit_RGBLCDShield.cpp-------------------//

/*************************************************** 
  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
 ****************************************************/


//#include "Adafruit_RGBLCDShield.h"

//#include <stdio.h>
//#include <string.h>
//#include <inttypes.h>
//#include <Wire.h>


// When the display powers up, it is configured as follows:
//
// 1. Display clear
// 2. Function set: 
//    DL = 1; 8-bit interface data 
//    N = 0; 1-line display 
//    F = 0; 5x8 dot character font 
// 3. Display on/off control: 
//    D = 0; Display off 
//    C = 0; Cursor off 
//    B = 0; Blinking off 
// 4. Entry mode set: 
//    I/D = 1; Increment by 1 
//    S = 0; No shift 
//
// Note, however, that resetting the Arduino doesn't reset the LCD, so we
// can't assume that its in that state when a sketch starts (and the
// RGBLCDShield constructor is called).

Adafruit_RGBLCDShield::Adafruit_RGBLCDShield() {
  _i2cAddr = 0;

  _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
  
  // the I/O expander pinout
  _rs_pin = 15;
  _rw_pin = 14;
  _enable_pin = 13;
  _data_pins[0] = 12;  // really d4
  _data_pins[1] = 11;  // really d5
  _data_pins[2] = 10;  // really d6
  _data_pins[3] = 9;  // really d7
  
  _button_pins[0] = 0;
  _button_pins[1] = 1;
  _button_pins[2] = 2;
  _button_pins[3] = 3;
  _button_pins[4] = 4;
  // we can't begin() yet :(
}




void Adafruit_RGBLCDShield::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)
{
  _rs_pin = rs;
  _rw_pin = rw;
  _enable_pin = enable;
  
  _data_pins[0] = d0;
  _data_pins[1] = d1;
  _data_pins[2] = d2;
  _data_pins[3] = d3; 
  _data_pins[4] = d4;
  _data_pins[5] = d5;
  _data_pins[6] = d6;
  _data_pins[7] = d7; 

  _i2cAddr = 255;

  _pinMode(_rs_pin, OUTPUT);
  // we can save 1 pin by not using RW. Indicate by passing 255 instead of pin#
  if (_rw_pin != 255) { 
    _pinMode(_rw_pin, OUTPUT);
  }
  _pinMode(_enable_pin, OUTPUT);
  

  if (fourbitmode)
    _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
  else 
    _displayfunction = LCD_8BITMODE | LCD_1LINE | LCD_5x8DOTS;
  
  begin(16, 1);  
}

void Adafruit_RGBLCDShield::begin(uint8_t cols, uint8_t lines, uint8_t dotsize) {
  // check if i2c
  if (_i2cAddr != 255) {
    //_i2c.begin(_i2cAddr);
    Wire.begin();
    _i2c.begin();

    _i2c.pinMode(8, OUTPUT);
    _i2c.pinMode(6, OUTPUT);
    _i2c.pinMode(7, OUTPUT);
    setBacklight(0x7);

    if (_rw_pin)
      _i2c.pinMode(_rw_pin, OUTPUT);

    _i2c.pinMode(_rs_pin, OUTPUT);
    _i2c.pinMode(_enable_pin, OUTPUT);
    for (uint8_t i=0; i<4; i++) 
      _i2c.pinMode(_data_pins[i], OUTPUT);

    for (uint8_t i=0; i<5; i++) {
      _i2c.pinMode(_button_pins[i], INPUT);
      _i2c.pullUp(_button_pins[i], 1);
    }
  }

  if (lines > 1) {
    _displayfunction |= LCD_2LINE;
  }
  _numlines = lines;
  _currline = 0;

  // for some 1 line displays you can select a 10 pixel high font
  if ((dotsize != 0) && (lines == 1)) {
    _displayfunction |= LCD_5x10DOTS;
  }

  // SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
  // according to datasheet, we need at least 40ms after power rises above 2.7V
  // before sending commands. Arduino can turn on way befer 4.5V so we'll wait 50
  delayMicroseconds(50000); 
  // Now we pull both RS and R/W low to begin commands
  _digitalWrite(_rs_pin, LOW);
  _digitalWrite(_enable_pin, LOW);
  if (_rw_pin != 255) { 
    _digitalWrite(_rw_pin, LOW);
  }
  
  //put the LCD into 4 bit or 8 bit mode
  if (! (_displayfunction & LCD_8BITMODE)) {
    // this is according to the hitachi HD44780 datasheet
    // figure 24, pg 46

    // we start in 8bit mode, try to set 4 bit mode
    write4bits(0x03);
    delayMicroseconds(4500); // wait min 4.1ms

    // second try
    write4bits(0x03);
    delayMicroseconds(4500); // wait min 4.1ms
    
    // third go!
    write4bits(0x03); 
    delayMicroseconds(150);

    // finally, set to 8-bit interface
    write4bits(0x02); 
  } else {
    // this is according to the hitachi HD44780 datasheet
    // page 45 figure 23

    // Send function set command sequence
    command(LCD_FUNCTIONSET | _displayfunction);
    delayMicroseconds(4500);  // wait more than 4.1ms

    // second try
    command(LCD_FUNCTIONSET | _displayfunction);
    delayMicroseconds(150);

    // third go
    command(LCD_FUNCTIONSET | _displayfunction);
  }

  // finally, set # lines, font size, etc.
  command(LCD_FUNCTIONSET | _displayfunction);  

  // turn the display on with no cursor or blinking default
  _displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;  
  display();

  // clear it off
  clear();

  // Initialize to default text direction (for romance languages)
  _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
  // set the entry mode
  command(LCD_ENTRYMODESET | _displaymode);

}

/********** high level commands, for the user! */
void Adafruit_RGBLCDShield::clear()
{
  command(LCD_CLEARDISPLAY);  // clear display, set cursor position to zero
  delayMicroseconds(2000);  // this command takes a long time!
}

void Adafruit_RGBLCDShield::home()
{
  command(LCD_RETURNHOME);  // set cursor position to zero
  delayMicroseconds(2000);  // this command takes a long time!
}

void Adafruit_RGBLCDShield::setCursor(uint8_t col, uint8_t row)
{
  int row_offsets[] = { 0x00, 0x40, 0x14, 0x54 };
  if ( row > _numlines ) {
    row = _numlines-1;    // we count rows starting w/0
  }
  
  command(LCD_SETDDRAMADDR | (col + row_offsets[row]));
}

// Turn the display on/off (quickly)
void Adafruit_RGBLCDShield::noDisplay() {
  _displaycontrol &= ~LCD_DISPLAYON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void Adafruit_RGBLCDShield::display() {
  _displaycontrol |= LCD_DISPLAYON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// Turns the underline cursor on/off
void Adafruit_RGBLCDShield::noCursor() {
  _displaycontrol &= ~LCD_CURSORON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void Adafruit_RGBLCDShield::cursor() {
  _displaycontrol |= LCD_CURSORON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// Turn on and off the blinking cursor
void Adafruit_RGBLCDShield::noBlink() {
  _displaycontrol &= ~LCD_BLINKON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void Adafruit_RGBLCDShield::blink() {
  _displaycontrol |= LCD_BLINKON;
  command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// These commands scroll the display without changing the RAM
void Adafruit_RGBLCDShield::scrollDisplayLeft(void) {
  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
}
void Adafruit_RGBLCDShield::scrollDisplayRight(void) {
  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
}

// This is for text that flows Left to Right
void Adafruit_RGBLCDShield::leftToRight(void) {
  _displaymode |= LCD_ENTRYLEFT;
  command(LCD_ENTRYMODESET | _displaymode);
}

// This is for text that flows Right to Left
void Adafruit_RGBLCDShield::rightToLeft(void) {
  _displaymode &= ~LCD_ENTRYLEFT;
  command(LCD_ENTRYMODESET | _displaymode);
}

// This will 'right justify' text from the cursor
void Adafruit_RGBLCDShield::autoscroll(void) {
  _displaymode |= LCD_ENTRYSHIFTINCREMENT;
  command(LCD_ENTRYMODESET | _displaymode);
}

// This will 'left justify' text from the cursor
void Adafruit_RGBLCDShield::noAutoscroll(void) {
  _displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
  command(LCD_ENTRYMODESET | _displaymode);
}

// Allows us to fill the first 8 CGRAM locations
// with custom characters
void Adafruit_RGBLCDShield::createChar(uint8_t location, uint8_t charmap[]) {
  location &= 0x7; // we only have 8 locations 0-7
  command(LCD_SETCGRAMADDR | (location << 3));
  for (int i=0; i<8; i++) {
    write(charmap[i]);
  }
  command(LCD_SETDDRAMADDR);  // unfortunately resets the location to 0,0
}

/*********** mid level commands, for sending data/cmds */

inline void Adafruit_RGBLCDShield::command(uint8_t value) {
  send(value, LOW);
}


inline size_t Adafruit_RGBLCDShield::write(uint8_t value) {
  send(value, HIGH);
  return 1;
}




/************ low level data pushing commands **********/

// little wrapper for i/o writes
void  Adafruit_RGBLCDShield::_digitalWrite(uint8_t p, uint8_t d) {
  if (_i2cAddr != 255) {
    // an i2c command
    _i2c.digitalWrite(p, d);
  } else {
    // straightup IO
    digitalWrite(p, d);
  }
}

// Allows to set the backlight, if the LCD backpack is used
void Adafruit_RGBLCDShield::setBacklight(uint8_t status) {
  // check if i2c or SPI
  _i2c.digitalWrite(8, ~(status >> 2) & 0x1);
  _i2c.digitalWrite(7, ~(status >> 1) & 0x1);
  _i2c.digitalWrite(6, ~status & 0x1);
}

// little wrapper for i/o directions
void  Adafruit_RGBLCDShield::_pinMode(uint8_t p, uint8_t d) {
  if (_i2cAddr != 255) {
    // an i2c command
    _i2c.pinMode(p, d);
  } else {
    // straightup IO
    //pinMode(p, d);
  }
}

// write either command or data, with automatic 4/8-bit selection
void Adafruit_RGBLCDShield::send(uint8_t value, uint8_t mode) {
  _digitalWrite(_rs_pin, mode);

  // if there is a RW pin indicated, set it low to Write
  if (_rw_pin != 255) { 
    _digitalWrite(_rw_pin, LOW);
  }
  
  if (_displayfunction & LCD_8BITMODE) {
    write8bits(value); 
  } else {
    write4bits(value>>4);
    write4bits(value);
  }
}

void Adafruit_RGBLCDShield::pulseEnable(void) {
  _digitalWrite(_enable_pin, LOW);
  delayMicroseconds(1);    
  _digitalWrite(_enable_pin, HIGH);
  delayMicroseconds(1);    // enable pulse must be >450ns
  _digitalWrite(_enable_pin, LOW);
  delayMicroseconds(100);   // commands need > 37us to settle
}

void Adafruit_RGBLCDShield::write4bits(uint8_t value) {
  if (_i2cAddr != 255) {
    uint16_t out = 0;

    out = _i2c.readGPIOAB();

    // speed up for i2c since its sluggish
    for (int i = 0; i < 4; i++) {
      out &= ~(1 << _data_pins[i]);
      out |= ((value >> i) & 0x1) << _data_pins[i];
    }

    // make sure enable is low
    out &= ~(1 << _enable_pin);

    _i2c.writeGPIOAB(out);

    // pulse enable
    delayMicroseconds(1);
    out |= (1 << _enable_pin);
    _i2c.writeGPIOAB(out);
    delayMicroseconds(1);
    out &= ~(1 << _enable_pin);
    _i2c.writeGPIOAB(out);   
    delayMicroseconds(100);

  } else {
    for (int i = 0; i < 4; i++) {
     _pinMode(_data_pins[i], OUTPUT);
     _digitalWrite(_data_pins[i], (value >> i) & 0x01);
    }
    pulseEnable();
  }
}

void Adafruit_RGBLCDShield::write8bits(uint8_t value) {
  for (int i = 0; i < 8; i++) {
    _pinMode(_data_pins[i], OUTPUT);
    _digitalWrite(_data_pins[i], (value >> i) & 0x01);
  }
  
  pulseEnable();
}

uint8_t Adafruit_RGBLCDShield::readButtons(void) {
  uint8_t reply = 0x1F;

  for (uint8_t i=0; i<5; i++) {
    reply &= ~((_i2c.digitalRead(_button_pins[i])) << i);
  }
  return reply;
}

//------------------Adafruit Hello World example for RGB LED shield---------//

/*********************

Example code for the Adafruit RGB Character LCD Shield and Library

This code displays text on the shield, and also reads the buttons on the keypad.
When a button is pressed, the backlight changes color.

**********************/

// include the library code:
//#include <Wire.h>
//#include <Adafruit_MCP23017.h>
//#include <Adafruit_RGBLCDShield.h>

// The shield uses the I2C SCL and SDA pins. On classic Arduinos
// this is Analog 4 and 5 so you can't use those for analogRead() anymore
// However, you can connect other I2C sensors to the I2C bus and share
// the I2C bus.
Adafruit_RGBLCDShield lcd = Adafruit_RGBLCDShield();

// These #defines make it easy to set the backlight color
#define RED 0x1
#define YELLOW 0x3
#define GREEN 0x2
#define TEAL 0x6
#define BLUE 0x4
#define VIOLET 0x5
#define WHITE 0x7

void setup() {
  // Debugging output
  Serial.begin(9600);
  // set up the LCD's number of columns and rows: 
  lcd.begin(16, 2);

  // Print a message to the LCD. We track how long it takes since
  // this library has been optimized a bit and we're proud of it :)
  int time = millis();
  lcd.print("Hello, world!");
  time = millis() - time;
  Serial.print("Took "); Serial.print(time); Serial.println(" ms");
  lcd.setBacklight(WHITE);
}

uint8_t i=0;
void loop() {
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print(millis()/1000);

  uint8_t buttons = lcd.readButtons();

  if (buttons) {
    lcd.clear();
    lcd.setCursor(0,0);
    if (buttons & BUTTON_UP) {
      lcd.print("UP ");
      lcd.setBacklight(RED);
    }
    if (buttons & BUTTON_DOWN) {
      lcd.print("DOWN ");
      lcd.setBacklight(YELLOW);
    }
    if (buttons & BUTTON_LEFT) {
      lcd.print("LEFT ");
      lcd.setBacklight(GREEN);
    }
    if (buttons & BUTTON_RIGHT) {
      lcd.print("RIGHT ");
      lcd.setBacklight(TEAL);
    }
    if (buttons & BUTTON_SELECT) {
      lcd.print("SELECT ");
      lcd.setBacklight(VIOLET);
    }
  }
}