LCD Library 1.2.0
LCD Library - LCD control class hierarchy library. Drop in replacement for the LiquidCrystal Library.
/Users/fmalpartida/development/ardWorkspace/LiquidCrystal_I2C/LiquiCrystal_I2C/LiquidCrystal_I2C.cpp
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00001 // ---------------------------------------------------------------------------
00002 // Created by Francisco Malpartida on 20/08/11.
00003 // Copyright 2011 - Under creative commons license 3.0:
00004 //        Attribution-ShareAlike CC BY-SA
00005 //
00006 // This software is furnished "as is", without technical support, and with no 
00007 // warranty, express or implied, as to its usefulness for any purpose.
00008 //
00009 // Thread Safe: No
00010 // Extendable: Yes
00011 //
00012 // @file LiquidCrystal_I2C.c
00013 // This file implements a basic liquid crystal library that comes as standard
00014 // in the Arduino SDK but using an I2C IO extension board.
00015 // 
00016 // @brief 
00017 // This is a basic implementation of the LiquidCrystal library of the
00018 // Arduino SDK. The original library has been reworked in such a way that 
00019 // this class implements the all methods to command an LCD based
00020 // on the Hitachi HD44780 and compatible chipsets using I2C extension
00021 // backpacks such as the I2CLCDextraIO with the PCF8574* I2C IO Expander ASIC.
00022 //
00023 // The functionality provided by this class and its base class is identical
00024 // to the original functionality of the Arduino LiquidCrystal library.
00025 //
00026 //
00027 //
00028 // @author F. Malpartida - fmalpartida@gmail.com
00029 // ---------------------------------------------------------------------------
00030 #if (ARDUINO <  100)
00031 #include <WProgram.h>
00032 #else
00033 #include <Arduino.h>
00034 #endif
00035 #include <inttypes.h>
00036 #include "I2CIO.h"
00037 #include "LiquidCrystal_I2C.h"
00038 
00039 // CONSTANT  definitions
00040 // ---------------------------------------------------------------------------
00041 
00042 // flags for backlight control
00043 #define LCD_NOBACKLIGHT 0x00
00044 #define LCD_BACKLIGHT   0xFF
00045 
00046 
00047 // CONSTRUCTORS
00048 // ---------------------------------------------------------------------------
00049 LiquidCrystal_I2C::LiquidCrystal_I2C( uint8_t lcd_Addr )
00050 {
00051    _Addr = lcd_Addr;
00052    
00053    _backlightPin  = 0x0;
00054    _backlightMask = LCD_NOBACKLIGHT;
00055    
00056    _En = EN;
00057    _Rw = RW;
00058    _Rs = RS;
00059    
00060    // Initialise default values data[0] pin 0, data[1] pin 1, ...
00061    for ( uint8_t i = 0; i < 4; i++ )
00062    {
00063       _data_pins[i] = ( 1 << i );
00064    }
00065 }
00066 
00067 LiquidCrystal_I2C::LiquidCrystal_I2C( uint8_t lcd_Addr, uint8_t En, uint8_t Rw,
00068                                       uint8_t Rs)
00069 {
00070    _Addr = lcd_Addr;
00071    
00072    _backlightPin  = 0;
00073    _backlightMask = LCD_NOBACKLIGHT;
00074    
00075    _En = ( 1 << En );
00076    _Rw = ( 1 << Rw );
00077    _Rs = ( 1 << Rs );
00078    
00079    // Initialise default values data[0] pin 0, data[1] pin 1, ...
00080    for ( uint8_t i = 0; i < 4; i++ )
00081    {
00082       _data_pins[i] = ( 1 << i );
00083    }
00084 }
00085 
00086 LiquidCrystal_I2C::LiquidCrystal_I2C( uint8_t lcd_Addr, uint8_t En, uint8_t Rw,
00087                                      uint8_t Rs, uint8_t d0, uint8_t d1,
00088                                      uint8_t d2, uint8_t d3 )
00089 {
00090    _Addr = lcd_Addr;
00091    
00092    _backlightPin  = 0;
00093    _backlightMask = LCD_NOBACKLIGHT;
00094 
00095    _En = ( 1 << En );
00096    _Rw = ( 1 << Rw );
00097    _Rs = ( 1 << Rs );
00098    
00099    // Initialise pin mapping
00100    _data_pins[0] = ( 1 << d0 );
00101    _data_pins[1] = ( 1 << d1 );
00102    _data_pins[2] = ( 1 << d2 );
00103    _data_pins[3] = ( 1 << d3 );
00104 }
00105 
00106 // PUBLIC METHODS
00107 // ---------------------------------------------------------------------------
00108 
00109 //
00110 // begin
00111 void LiquidCrystal_I2C::begin(uint8_t cols, uint8_t lines, uint8_t dotsize) 
00112 {
00113    
00114    init();     // Initialise the I2C expander interface
00115    LCD::begin ( cols, lines, dotsize );   
00116 }
00117 
00118 
00119 // User commands - users can expand this section
00120 //----------------------------------------------------------------------------
00121 
00122 // Turn the (optional) backlight off/on
00123 //
00124 // setBacklight
00125 void LiquidCrystal_I2C::setBacklight( uint8_t mode ) 
00126 {
00127    if ( mode == HIGH )
00128    {
00129       _backlightMask = _backlightPin & LCD_BACKLIGHT;
00130       
00131    }
00132    else 
00133    {
00134       _backlightMask = _backlightPin & LCD_NOBACKLIGHT;
00135    }
00136    _i2cio.write( _backlightMask );
00137 }
00138 
00139 //
00140 // setBacklightPin
00141 void LiquidCrystal_I2C::setBacklightPin ( uint8_t pin )
00142 {
00143    _backlightPin = ( 1 << pin );
00144 }
00145 
00146 // PRIVATE METHODS
00147 // ---------------------------------------------------------------------------
00148 
00149 //
00150 // init
00151 int LiquidCrystal_I2C::init()
00152 {
00153    int status = 0;
00154    
00155    // initialize the backpack IO expander
00156    // and display functions.
00157    // ------------------------------------------------------------------------
00158    if ( _i2cio.begin ( _Addr ) == 1 )
00159    {
00160       _i2cio.portMode ( OUTPUT );  // Set the entire IO extender to OUTPUT
00161       _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
00162       status = 1;
00163       _i2cio.write(0);  // Set the entire port to LOW
00164    }
00165    return ( status );
00166 }
00167 
00168 // low level data pushing commands
00169 //----------------------------------------------------------------------------
00170 
00171 //
00172 // send - write either command or data
00173 void LiquidCrystal_I2C::send(uint8_t value, uint8_t mode) 
00174 {
00175    // No need to use the delay routines since the time taken to write takes
00176    // longer that what is needed both for toggling and enable pin an to execute
00177    // the command.
00178    write4bits( (value >> 4), mode );
00179    write4bits( (value & 0x0F), mode);
00180 }
00181 
00182 //
00183 // write4bits
00184 void LiquidCrystal_I2C::write4bits ( uint8_t value, uint8_t mode ) 
00185 {
00186    uint8_t pinMapValue = 0;
00187    
00188    // Map the value to LCD pin mapping
00189    // --------------------------------
00190    for ( uint8_t i = 0; i < 4; i++ )
00191    {
00192       if ( ( value & 0x1 ) == 1 )
00193       {
00194          pinMapValue |= _data_pins[i];
00195       }
00196       value = ( value >> 1 );
00197    }
00198    
00199    // Is it a command or data
00200    // -----------------------
00201    if ( mode == DATA )
00202    {
00203       mode = _Rs;
00204    }
00205    
00206    pinMapValue |= mode | _backlightMask;
00207    _i2cio.write ( pinMapValue );
00208    pulseEnable ( pinMapValue );
00209 }
00210 
00211 //
00212 // pulseEnable
00213 void LiquidCrystal_I2C::pulseEnable (uint8_t _data)
00214 {
00215    _i2cio.write (_data | _En);   // En HIGH
00216    _i2cio.write (_data & ~_En);  // En LOW
00217 }
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