File content as of revision 0:4f1c764a42d3:

/***************************************************
  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_I2C_LCD.h"

#include <stdio.h>
#include <string.h>
#include <inttypes.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_I2C_LCD::Adafruit_I2C_LCD(I2C *master, uint8_t cols, uint8_t lines, uint8_t dotsize)
{
    _i2c = new Adafruit_MCP23017(master);
    _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;

    begin(cols, lines, dotsize);
}

Adafruit_I2C_LCD::~Adafruit_I2C_LCD()
{
    delete _i2c;
}

/********** high level commands, for the user! */
void Adafruit_I2C_LCD::clear()
{
    command(LCD_CLEARDISPLAY);  // clear display, set cursor position to zero
    wait_us(2000);  // this command takes a long time!
}

void Adafruit_I2C_LCD::home()
{
    command(LCD_RETURNHOME);  // set cursor position to zero
    wait_us(2000);  // this command takes a long time!
}

void Adafruit_I2C_LCD::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_I2C_LCD::noDisplay()
{
    _displaycontrol &= ~LCD_DISPLAYON;
    command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void Adafruit_I2C_LCD::display()
{
    _displaycontrol |= LCD_DISPLAYON;
    command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// Turns the underline cursor on/off
void Adafruit_I2C_LCD::noCursor()
{
    _displaycontrol &= ~LCD_CURSORON;
    command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void Adafruit_I2C_LCD::cursor()
{
    _displaycontrol |= LCD_CURSORON;
    command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// Turn on and off the blinking cursor
void Adafruit_I2C_LCD::noBlink()
{
    _displaycontrol &= ~LCD_BLINKON;
    command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void Adafruit_I2C_LCD::blink()
{
    _displaycontrol |= LCD_BLINKON;
    command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// These commands scroll the display without changing the RAM
void Adafruit_I2C_LCD::scrollDisplayLeft(void)
{
    command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
}
void Adafruit_I2C_LCD::scrollDisplayRight(void)
{
    command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
}

// This is for text that flows Left to Right
void Adafruit_I2C_LCD::leftToRight(void)
{
    _displaymode |= LCD_ENTRYLEFT;
    command(LCD_ENTRYMODESET | _displaymode);
}

// This is for text that flows Right to Left
void Adafruit_I2C_LCD::rightToLeft(void)
{
    _displaymode &= ~LCD_ENTRYLEFT;
    command(LCD_ENTRYMODESET | _displaymode);
}

// This will 'right justify' text from the cursor
void Adafruit_I2C_LCD::autoscroll(void)
{
    _displaymode |= LCD_ENTRYSHIFTINCREMENT;
    command(LCD_ENTRYMODESET | _displaymode);
}

// This will 'left justify' text from the cursor
void Adafruit_I2C_LCD::noAutoscroll(void)
{
    _displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
    command(LCD_ENTRYMODESET | _displaymode);
}

// Allows us to fill the first 8 CGRAM locations
// with custom characters
void Adafruit_I2C_LCD::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 */

void Adafruit_I2C_LCD::command(uint8_t value)
{
    send(value, LOW);
}


void Adafruit_I2C_LCD::write(uint8_t value)
{
    send(value, HIGH);
}

void Adafruit_I2C_LCD::print(char *array, size_t array_size)
{
    for(size_t i = 0; i < array_size; i++){
        if(array[i] == '\0')
            break;
        send(array[i], HIGH);   
    }
}

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

// little wrapper for i/o writes
void  Adafruit_I2C_LCD::_digitalWrite(uint8_t p, uint8_t d)
{
    _i2c->digitalWrite(p, d);
}

// Allows to set the backlight, if the LCD backpack is used
void Adafruit_I2C_LCD::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_I2C_LCD::_pinMode(uint8_t p, uint8_t d)
{
    _i2c->pinMode(p, d);
}

void Adafruit_I2C_LCD::begin(uint8_t cols, uint8_t lines, uint8_t dotsize)
{
    _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
    wait_us(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);
        wait_us(4500); // wait min 4.1ms

        // second try
        write4bits(0x03);
        wait_us(4500); // wait min 4.1ms

        // third go!
        write4bits(0x03);
        wait_us(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);
        wait_us(4500);  // wait more than 4.1ms

        // second try
        command(LCD_FUNCTIONSET | _displayfunction);
        wait_us(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);

}

// write either command or data, with automatic 4/8-bit selection
void Adafruit_I2C_LCD::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_I2C_LCD::pulseEnable(void)
{
    _digitalWrite(_enable_pin, LOW);
    wait_us(1);
    _digitalWrite(_enable_pin, HIGH);
    wait_us(1);    // enable pulse must be >450ns
    _digitalWrite(_enable_pin, LOW);
    wait_us(100);   // commands need > 37us to settle
}

void Adafruit_I2C_LCD::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
        wait_us(1);
        out |= (1 << _enable_pin);
        _i2c->writeGPIOAB(out);
        wait_us(1);
        out &= ~(1 << _enable_pin);
        _i2c->writeGPIOAB(out);
        wait_us(100);

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

void Adafruit_I2C_LCD::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_I2C_LCD::readButtons(void)
{
    uint8_t reply = 0x1F;

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