LiquidCrystal_I2C.cpp

// Based on the work by DFRobot

#include "LiquidCrystal_I2C.h"
#include <inttypes.h>
#if defined(ARDUINO) && ARDUINO >= 100
  #include <Arduino.h>
  #define printIIC(args)    _i2c_bus.write(args)
#else
  #include <WProgram.h>
  #define printIIC(args)    _i2c_bus.send(args)
#endif

#if defined(ARDUINO) && ARDUINO >= 100
  inline size_t LiquidCrystal_I2C::write(uint8_t value) {
#else
  inline void LiquidCrystal_I2C::write(uint8_t value) {
#endif
    switch (value) {
    case 13: // Carriage Return
      setCursor(0, _currentrow);
      break;
    case 10: // Line Feed
      setCursor(0, _currentrow + 1);
      break; 
    default:
      send(value, Rs);
    }
    #if defined(ARDUINO) && ARDUINO >= 100
        return 1;
    #endif
}

#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
// LiquidCrystal constructor is called).

LiquidCrystal_I2C::LiquidCrystal_I2C(uint8_t lcd_addr,uint8_t lcd_cols,uint8_t lcd_rows, uint8_t charsize)
{
  _addr = lcd_addr;
  _cols = lcd_cols;
  _rows = lcd_rows;
  _charsize = charsize;
  _backlightval = LCD_NOBACKLIGHT;
}

// Optional argument i2c_bus gives the opportunity to use Wire1 instead of Wire on the Arduino models that have two I2C buses (such as the Arduino DUE)
void LiquidCrystal_I2C::begin(TwoWire &i2c_bus) {
    _i2c_bus = i2c_bus;
    _i2c_bus.begin();
    _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
    reset();
}
    
void LiquidCrystal_I2C::reset(uint8_t cols, uint8_t lines, uint8_t dotsize) {
    _cols = cols;
    _rows = lines;
    _charsize = dotsize;
    reset();
}
    
void LiquidCrystal_I2C::reset() {
    if (_rows > 1) {
        _displayfunction |= LCD_2LINE;
    }

    // for some 1 line displays you can select a 10 pixel high font
    if ((_charsize != 0) && (_rows == 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
    delay(50); 
  
    // Now we pull both RS and R/W low to begin commands
    expanderWrite(_backlightval);    // reset expanderand turn backlight off (Bit 8 =1)
    delay(1000);

      //put the LCD into 4 bit mode
    // 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 << 4);
    delayMicroseconds(4500); // wait min 4.1ms
   
    // second try
    write4bits(0x03 << 4);
    delayMicroseconds(4500); // wait min 4.1ms
   
    // third go!
    write4bits(0x03 << 4); 
    delayMicroseconds(150);
   
    // finally, set to 4-bit interface
    write4bits(0x02 << 4); 

    // 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 roman languages)
    _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
    
    // set the entry mode
    command(LCD_ENTRYMODESET | _displaymode);
    
    home();
}

/********** high level commands, for the user! */
void LiquidCrystal_I2C::clear(){
    command(LCD_CLEARDISPLAY);// clear display, set cursor position to zero
    delayMicroseconds(2000);  // this command takes a long time!
    _currentrow = 0;
}

void LiquidCrystal_I2C::home(){
    command(LCD_RETURNHOME);  // set cursor position to zero
    delayMicroseconds(2000);  // this command takes a long time!
    _currentrow = 0;
}

void LiquidCrystal_I2C::setCursor(uint8_t col, uint8_t row){
    int row_offsets[] = { 0x00, 0x40, 0x14, 0x54 };
    if ( row > _rows ) {
        row = _rows-1;    // we count rows starting w/0
    }
    command(LCD_SETDDRAMADDR | (col + row_offsets[row]));
    _currentrow = row;
}

// Turn the display on/off (quickly)
void LiquidCrystal_I2C::noDisplay() {
    _displaycontrol &= ~LCD_DISPLAYON;
    command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void LiquidCrystal_I2C::display() {
    _displaycontrol |= LCD_DISPLAYON;
    command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// Turns the underline cursor on/off
void LiquidCrystal_I2C::noCursor() {
    _displaycontrol &= ~LCD_CURSORON;
    command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void LiquidCrystal_I2C::cursor() {
    _displaycontrol |= LCD_CURSORON;
    command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// Turn on and off the blinking cursor
void LiquidCrystal_I2C::noBlink() {
    _displaycontrol &= ~LCD_BLINKON;
    command(LCD_DISPLAYCONTROL | _displaycontrol);
}
void LiquidCrystal_I2C::blink() {
    _displaycontrol |= LCD_BLINKON;
    command(LCD_DISPLAYCONTROL | _displaycontrol);
}

// These commands scroll the display without changing the RAM
void LiquidCrystal_I2C::scrollDisplayLeft(void) {
    command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
}
void LiquidCrystal_I2C::scrollDisplayRight(void) {
    command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
}

// This is for text that flows Left to Right
void LiquidCrystal_I2C::leftToRight(void) {
    _displaymode |= LCD_ENTRYLEFT;
    command(LCD_ENTRYMODESET | _displaymode);
}

// This is for text that flows Right to Left
void LiquidCrystal_I2C::rightToLeft(void) {
    _displaymode &= ~LCD_ENTRYLEFT;
    command(LCD_ENTRYMODESET | _displaymode);
}

// This will 'right justify' text from the cursor
void LiquidCrystal_I2C::autoscroll(void) {
    _displaymode |= LCD_ENTRYSHIFTINCREMENT;
    command(LCD_ENTRYMODESET | _displaymode);
}

// This will 'left justify' text from the cursor
void LiquidCrystal_I2C::noAutoscroll(void) {
    _displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
    command(LCD_ENTRYMODESET | _displaymode);
}

// Allows us to fill the first 8 CGRAM locations
// with custom characters
void LiquidCrystal_I2C::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]);
    }
}

//createChar with PROGMEM input
void LiquidCrystal_I2C::createChar(uint8_t location, const char *charmap) {
    location &= 0x7; // we only have 8 locations 0-7
    command(LCD_SETCGRAMADDR | (location << 3));
    for (int i=0; i<8; i++) {
        write(pgm_read_byte_near(charmap++));
    }
}

// Turn the (optional) backlight off/on
void LiquidCrystal_I2C::noBacklight(void) {
    _backlightval=LCD_NOBACKLIGHT;
    expanderWrite(0);
}

void LiquidCrystal_I2C::backlight(void) {
    _backlightval=LCD_BACKLIGHT;
    expanderWrite(0);
}

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

inline void LiquidCrystal_I2C::command(uint8_t value) {
    send(value, 0);
}


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

// write either command or data
void LiquidCrystal_I2C::send(uint8_t value, uint8_t mode) {
    uint8_t highnib=value&0xf0;
    uint8_t lownib=(value<<4)&0xf0;
    write4bits((highnib)|mode);
    write4bits((lownib)|mode); 
}

void LiquidCrystal_I2C::write4bits(uint8_t value) {
    expanderWrite(value);
    pulseEnable(value);
}

void LiquidCrystal_I2C::expanderWrite(uint8_t _data){                                        
    _i2c_bus.beginTransmission(_addr);
    printIIC((int)(_data) | _backlightval);
    _i2c_bus.endTransmission();   
}

void LiquidCrystal_I2C::pulseEnable(uint8_t _data){
    expanderWrite(_data | En);    // En high
    delayMicroseconds(1);        // enable pulse must be >450ns
    
    expanderWrite(_data & ~En);    // En low
    delayMicroseconds(50);        // commands need > 37us to settle
} 


// Alias functions

void LiquidCrystal_I2C::cursor_on(){
    cursor();
}

void LiquidCrystal_I2C::cursor_off(){
    noCursor();
}

void LiquidCrystal_I2C::blink_on(){
    blink();
}

void LiquidCrystal_I2C::blink_off(){
    noBlink();
}

void LiquidCrystal_I2C::load_custom_character(uint8_t char_num, uint8_t *rows){
    createChar(char_num, rows);
}

void LiquidCrystal_I2C::setBacklight(uint8_t new_val){
    if (new_val) {
        backlight();        // turn backlight on
    } else {
        noBacklight();        // turn backlight off
    }
}

void LiquidCrystal_I2C::printstr(const char c[]){
    //This function is not identical to the function used for "real" I2C displays
    //it's here so the user sketch doesn't have to be changed 
    print(c);
}


// unsupported API functions
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
void LiquidCrystal_I2C::off(){}
void LiquidCrystal_I2C::on(){}
void LiquidCrystal_I2C::setDelay (int cmdDelay,int charDelay) {}
uint8_t LiquidCrystal_I2C::status(){return 0;}
uint8_t LiquidCrystal_I2C::keypad (){return 0;}
uint8_t LiquidCrystal_I2C::init_bargraph(uint8_t graphtype){return 0;}
void LiquidCrystal_I2C::draw_horizontal_graph(uint8_t row, uint8_t column, uint8_t len,  uint8_t pixel_col_end){}
void LiquidCrystal_I2C::draw_vertical_graph(uint8_t row, uint8_t column, uint8_t len,  uint8_t pixel_row_end){}
void LiquidCrystal_I2C::setContrast(uint8_t new_val){}
#pragma GCC diagnostic pop