LCD Library 1.1.7
LCD Library - LCD control class hierarchy library. Drop in replacement for the LiquidCrystal Library.
/Users/fmalpartida/development/ardWorkspace/LiquidCrystal_I2C/LiquiCrystal_I2C/LiquidCrystal.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 //LiquidCrystal
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.cpp
00013 // This file implements a basic liquid crystal library that comes as standard
00014 // in the Arduino SDK.
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 the parallel port of
00021 // the LCD (4 bit and 8 bit).
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 // This library is only compatible with Arduino's SDK version 1.0
00028 //
00029 //
00030 // @author F. Malpartida - fmalpartida@gmail.com
00031 // ---------------------------------------------------------------------------
00032 #include <stdio.h>
00033 #include <string.h>
00034 #include <inttypes.h>
00035 
00036 #if (ARDUINO <  100)
00037 #include <WProgram.h>
00038 #else
00039 #include <Arduino.h>
00040 #endif
00041 #include <LiquidCrystal.h>
00042 
00043 // STATIC helper functions
00044 // ---------------------------------------------------------------------------
00045 
00046 
00047 // CONSTRUCTORS
00048 // ---------------------------------------------------------------------------
00049 LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable,
00050                              uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
00051                              uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
00052 {
00053    init(LCD_8BIT, rs, rw, enable, d0, d1, d2, d3, d4, d5, d6, d7);
00054 }
00055 
00056 LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t enable,
00057                              uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
00058                              uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
00059 {
00060    init(LCD_8BIT, rs, 255, enable, d0, d1, d2, d3, d4, d5, d6, d7);
00061 }
00062 
00063 LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable,
00064                              uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3)
00065 {
00066    init(LCD_4BIT, rs, rw, enable, d0, d1, d2, d3, 0, 0, 0, 0);
00067 }
00068 
00069 LiquidCrystal::LiquidCrystal(uint8_t rs,  uint8_t enable,
00070                              uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3)
00071 {
00072    init(LCD_4BIT, rs, 255, enable, d0, d1, d2, d3, 0, 0, 0, 0);
00073 }
00074 
00075 // PRIVATE METHODS
00076 // ---------------------------------------------------------------------------
00077 
00078 // When the display powers up, it is configured as follows:
00079 //
00080 // 1. Display clear
00081 // 2. Function set: 
00082 //    DL = 1; 8-bit interface data 
00083 //    N = 0; 1-line display 
00084 //    F = 0; 5x8 dot character font 
00085 // 3. Display on/off control: 
00086 //    D = 0; Display off 
00087 //    C = 0; Cursor off 
00088 //    B = 0; Blinking off 
00089 // 4. Entry mode set: 
00090 //    I/D = 1; Increment by 1 
00091 //    S = 0; No shift 
00092 //
00093 // Note, however, that resetting the Arduino doesn't reset the LCD, so we
00094 // can't assume that its in that state when a sketch starts (and the
00095 // LiquidCrystal constructor is called).
00096 // A call to begin() will reinitialize the LCD.
00097 //
00098 // init
00099 void LiquidCrystal::init(uint8_t fourbitmode, uint8_t rs, uint8_t rw, uint8_t enable,
00100                          uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
00101                          uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
00102 {
00103    uint8_t i;
00104    
00105    // Initialize the IO pins
00106    // -----------------------
00107    
00108    _rs_pin = rs;
00109    _rw_pin = rw;
00110    _enable_pin = enable;
00111    
00112    _data_pins[0] = d0;
00113    _data_pins[1] = d1;
00114    _data_pins[2] = d2;
00115    _data_pins[3] = d3; 
00116    _data_pins[4] = d4;
00117    _data_pins[5] = d5;
00118    _data_pins[6] = d6;
00119    _data_pins[7] = d7;
00120    
00121    // Initialize the IO port direction to OUTPUT
00122    // ------------------------------------------
00123    
00124    for ( i = 0; i < 4; i++ )
00125    {
00126       pinMode ( _data_pins[i], OUTPUT );
00127    }
00128    
00129    // Initialize the rest of the ports if it is an 8bit controlled LCD
00130    // ----------------------------------------------------------------
00131    
00132    if ( !fourbitmode )
00133    {
00134       for ( i = 4; i < 8; i++ )
00135       {
00136          pinMode ( _data_pins[i], OUTPUT );
00137       }
00138    }
00139    pinMode(_rs_pin, OUTPUT);
00140    
00141    // we can save 1 pin by not using RW. Indicate by passing 255 instead of pin#
00142    if (_rw_pin != 255) 
00143    { 
00144       pinMode(_rw_pin, OUTPUT);
00145    }
00146    
00147    pinMode(_enable_pin, OUTPUT);
00148    
00149    // Initialise displaymode functions to defaults: LCD_1LINE and LCD_5x8DOTS
00150    // -------------------------------------------------------------------------
00151    if (fourbitmode)
00152       _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
00153    else 
00154       _displayfunction = LCD_8BITMODE | LCD_1LINE | LCD_5x8DOTS;
00155 }
00156 
00157 // PUBLIC METHODS
00158 // ---------------------------------------------------------------------------
00159 
00160 //
00161 // begin
00162 void LiquidCrystal::begin(uint8_t cols, uint8_t lines, uint8_t dotsize) 
00163 {
00164    if (lines > 1) 
00165    {
00166       _displayfunction |= LCD_2LINE;
00167    }
00168    _numlines = lines;
00169    _cols = cols;
00170    
00171    // for some 1 line displays you can select a 10 pixel high font
00172    // ------------------------------------------------------------
00173    if ((dotsize != 0) && (lines == 1)) 
00174    {
00175       _displayfunction |= LCD_5x10DOTS;
00176    }
00177    
00178    // SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
00179    // according to datasheet, we need at least 40ms after power rises above 2.7V
00180    // before sending commands. Arduino can turn on way before 4.5V so we'll wait 
00181    // 50
00182    // ---------------------------------------------------------------------------
00183    delayMicroseconds(50000); 
00184    
00185    // Now we pull both RS and R/W low to begin commands
00186    digitalWrite(_rs_pin, LOW);
00187    digitalWrite(_enable_pin, LOW);
00188    
00189    if (_rw_pin != 255) 
00190    { 
00191       digitalWrite(_rw_pin, LOW);
00192    }
00193    
00194    //put the LCD into 4 bit or 8 bit mode
00195    // -------------------------------------
00196    if (! (_displayfunction & LCD_8BITMODE)) 
00197    {
00198       // this is according to the hitachi HD44780 datasheet
00199       // figure 24, pg 46
00200       
00201       // we start in 8bit mode, try to set 4 bit mode
00202       writeNbits(0x03, 4);
00203       delayMicroseconds(4500); // wait min 4.1ms
00204       
00205       // second try
00206       writeNbits(0x03, 4);
00207       delayMicroseconds(4500); // wait min 4.1ms
00208       
00209       // third go!
00210       writeNbits(0x03, 4); 
00211       delayMicroseconds(150);
00212       
00213       // finally, set to 4-bit interface
00214       writeNbits(0x02, 4); 
00215    } 
00216    else 
00217    {
00218       // this is according to the hitachi HD44780 datasheet
00219       // page 45 figure 23
00220       
00221       // Send function set command sequence
00222       command(LCD_FUNCTIONSET | _displayfunction);
00223       delayMicroseconds(4500);  // wait more than 4.1ms
00224       
00225       // second try
00226       command(LCD_FUNCTIONSET | _displayfunction);
00227       delayMicroseconds(150);
00228       
00229       // third go
00230       command(LCD_FUNCTIONSET | _displayfunction);
00231    }
00232    
00233    // finally, set # lines, font size, etc.
00234    command(LCD_FUNCTIONSET | _displayfunction);  
00235    
00236    // turn the display on with no cursor or blinking default
00237    _displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;  
00238    display();
00239    
00240    // clear the LCD
00241    clear();
00242    
00243    // Initialize to default text direction (for romance languages)
00244    _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
00245    // set the entry mode
00246    command(LCD_ENTRYMODESET | _displaymode);
00247    
00248 }
00249 
00250 /************ low level data pushing commands **********/
00251 
00252 // send
00253 void LiquidCrystal::send(uint8_t value, uint8_t mode) 
00254 {
00255    digitalWrite( _rs_pin, mode );
00256    
00257    // if there is a RW pin indicated, set it low to Write
00258    // ---------------------------------------------------
00259    if (_rw_pin != 255) 
00260    { 
00261       digitalWrite(_rw_pin, LOW);
00262    }
00263    
00264    if (_displayfunction & LCD_8BITMODE)
00265    {
00266       writeNbits(value, 8); 
00267    } 
00268    else 
00269    {
00270       writeNbits ( value >> 4, 4 );
00271       writeNbits ( value, 4 );
00272    }
00273    waitUsec ( EXEC_TIME ); // wait for the command to execute by the LCD
00274 }
00275 
00276 //
00277 // pulseEnable
00278 void LiquidCrystal::pulseEnable(void) 
00279 {
00280    // There is no need for the delays, since the digitalWrite operation
00281    // takes longer.
00282    digitalWrite(_enable_pin, HIGH);   
00283    waitUsec(1);          // enable pulse must be > 450ns   
00284    digitalWrite(_enable_pin, LOW);
00285    waitUsec(20);
00286 }
00287 
00288 //
00289 // write4bits
00290 void LiquidCrystal::writeNbits(uint8_t value, uint8_t numBits) 
00291 {
00292    for (uint8_t i = 0; i < numBits; i++) 
00293    {
00294       digitalWrite(_data_pins[i], (value >> i) & 0x01);
00295    }
00296    pulseEnable();
00297 }
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