LCD Library 1.3.0
LCD Library - LCD control class hierarchy library. Drop in replacement for the LiquidCrystal Library.
LCD.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 LCD.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 HD44780 library of the
00018 // Arduino SDK. This library is a refactored version of the one supplied
00019 // in the Arduino SDK in such a way that it simplifies its extension
00020 // to support other mechanism to communicate to LCDs such as I2C, Serial, SR, ...
00021 // The original library has been reworked in such a way that this will be
00022 // the base class implementing all generic methods to command an LCD based
00023 // on the Hitachi HD44780 and compatible chipsets.
00024 //
00025 // This base class is a pure abstract class and needs to be extended. As reference,
00026 // it has been extended to drive 4 and 8 bit mode control, LCDs and I2C extension
00027 // backpacks such as the I2CLCDextraIO using the PCF8574* I2C IO Expander ASIC.
00028 //
00029 //
00030 // @version API 1.1.0
00031 //
00032 // 2012.03.29 bperrybap - changed comparision to use LCD_5x8DOTS rather than 0
00033 // @author F. Malpartida - fmalpartida@gmail.com
00034 // ---------------------------------------------------------------------------
00035 #include <stdio.h>
00036 #include <string.h>
00037 #include <inttypes.h>
00038 
00039 #if (ARDUINO <  100)
00040 #include <WProgram.h>
00041 #else
00042 #include <Arduino.h>
00043 #endif
00044 
00045 #include "LCD.h"
00046 
00047 // CLASS CONSTRUCTORS
00048 // ---------------------------------------------------------------------------
00049 // Constructor
00050 LCD::LCD () 
00051 {
00052    
00053 }
00054 
00055 // PUBLIC METHODS
00056 // ---------------------------------------------------------------------------
00057 // When the display powers up, it is configured as follows:
00058 // 0. LCD starts in 8 bit mode
00059 // 1. Display clear
00060 // 2. Function set: 
00061 //    DL = 1; 8-bit interface data 
00062 //    N = 0; 1-line display 
00063 //    F = 0; 5x8 dot character font 
00064 // 3. Display on/off control: 
00065 //    D = 0; Display off 
00066 //    C = 0; Cursor off 
00067 //    B = 0; Blinking off 
00068 // 4. Entry mode set: 
00069 //    I/D = 1; Increment by 1 
00070 //    S = 0; No shift 
00071 //
00072 // Note, however, that resetting the Arduino doesn't reset the LCD, so we
00073 // can't assume that its in that state when a application starts (and the
00074 // LiquidCrystal constructor is called).
00075 // A call to begin() will reinitialize the LCD.
00076 //
00077 void LCD::begin(uint8_t cols, uint8_t lines, uint8_t dotsize) 
00078 {
00079    if (lines > 1) 
00080    {
00081       _displayfunction |= LCD_2LINE;
00082    }
00083    _numlines = lines;
00084    _cols = cols;
00085    
00086    // for some 1 line displays you can select a 10 pixel high font
00087    // ------------------------------------------------------------
00088    if ((dotsize != LCD_5x8DOTS) && (lines == 1)) 
00089    {
00090       _displayfunction |= LCD_5x10DOTS;
00091    }
00092    
00093    // SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
00094    // according to datasheet, we need at least 40ms after power rises above 2.7V
00095    // before sending commands. Arduino can turn on way before 4.5V so we'll wait 
00096    // 50
00097    // ---------------------------------------------------------------------------
00098    delay (100); // 100ms delay
00099    
00100    //put the LCD into 4 bit or 8 bit mode
00101    // -------------------------------------
00102    if (! (_displayfunction & LCD_8BITMODE)) 
00103    {
00104       // this is according to the hitachi HD44780 datasheet
00105       // figure 24, pg 46
00106       
00107       // we start in 8bit mode, try to set 4 bit mode
00108       // Special case of "Function Set"
00109       send(0x03, FOUR_BITS);
00110       delayMicroseconds(4500); // wait min 4.1ms
00111       
00112       // second try
00113       send ( 0x03, FOUR_BITS );
00114       delayMicroseconds(150); // wait min 100us
00115       
00116       // third go!
00117       send( 0x03, FOUR_BITS );
00118       delayMicroseconds(150); // wait min of 100us
00119       
00120       // finally, set to 4-bit interface
00121       send ( 0x02, FOUR_BITS );
00122       delayMicroseconds(150); // wait min of 100us
00123 
00124    } 
00125    else 
00126    {
00127       // this is according to the hitachi HD44780 datasheet
00128       // page 45 figure 23
00129       
00130       // Send function set command sequence
00131       command(LCD_FUNCTIONSET | _displayfunction);
00132       delayMicroseconds(4500);  // wait more than 4.1ms
00133       
00134       // second try
00135       command(LCD_FUNCTIONSET | _displayfunction);
00136       delayMicroseconds(150);
00137       
00138       // third go
00139       command(LCD_FUNCTIONSET | _displayfunction);
00140       delayMicroseconds(150);
00141 
00142    }
00143    
00144    // finally, set # lines, font size, etc.
00145    command(LCD_FUNCTIONSET | _displayfunction);
00146    delayMicroseconds ( 60 );  // wait more
00147    
00148    // turn the display on with no cursor or blinking default
00149    _displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;  
00150    display();
00151    
00152    // clear the LCD
00153    clear();
00154    
00155    // Initialize to default text direction (for romance languages)
00156    _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
00157    // set the entry mode
00158    command(LCD_ENTRYMODESET | _displaymode);
00159 
00160    backlight();
00161 
00162 }
00163 
00164 // Common LCD Commands
00165 // ---------------------------------------------------------------------------
00166 void LCD::clear()
00167 {
00168    command(LCD_CLEARDISPLAY);             // clear display, set cursor position to zero
00169    delayMicroseconds(HOME_CLEAR_EXEC);    // this command is time consuming
00170 }
00171 
00172 void LCD::home()
00173 {
00174    command(LCD_RETURNHOME);             // set cursor position to zero
00175    delayMicroseconds(HOME_CLEAR_EXEC);  // This command is time consuming
00176 }
00177 
00178 void LCD::setCursor(uint8_t col, uint8_t row)
00179 {
00180    const byte row_offsetsDef[]   = { 0x00, 0x40, 0x14, 0x54 }; // For regular LCDs
00181    const byte row_offsetsLarge[] = { 0x00, 0x40, 0x10, 0x50 }; // For 16x4 LCDs
00182    
00183    if ( row >= _numlines ) 
00184    {
00185       row = _numlines-1;    // rows start at 0
00186    }
00187    
00188    // 16x4 LCDs have special memory map layout
00189    // ----------------------------------------
00190    if ( _cols == 16 && _numlines == 4 )
00191    {
00192       command(LCD_SETDDRAMADDR | (col + row_offsetsLarge[row]));
00193    }
00194    else 
00195    {
00196       command(LCD_SETDDRAMADDR | (col + row_offsetsDef[row]));
00197    }
00198    
00199 }
00200 
00201 // Turn the display on/off
00202 void LCD::noDisplay() 
00203 {
00204    _displaycontrol &= ~LCD_DISPLAYON;
00205    command(LCD_DISPLAYCONTROL | _displaycontrol);
00206 }
00207 
00208 void LCD::display() 
00209 {
00210    _displaycontrol |= LCD_DISPLAYON;
00211    command(LCD_DISPLAYCONTROL | _displaycontrol);
00212 }
00213 
00214 // Turns the underline cursor on/off
00215 void LCD::noCursor() 
00216 {
00217    _displaycontrol &= ~LCD_CURSORON;
00218    command(LCD_DISPLAYCONTROL | _displaycontrol);
00219 }
00220 void LCD::cursor() 
00221 {
00222    _displaycontrol |= LCD_CURSORON;
00223    command(LCD_DISPLAYCONTROL | _displaycontrol);
00224 }
00225 
00226 // Turns on/off the blinking cursor
00227 void LCD::noBlink() 
00228 {
00229    _displaycontrol &= ~LCD_BLINKON;
00230    command(LCD_DISPLAYCONTROL | _displaycontrol);
00231 }
00232 
00233 void LCD::blink() 
00234 {
00235    _displaycontrol |= LCD_BLINKON;
00236    command(LCD_DISPLAYCONTROL | _displaycontrol);
00237 }
00238 
00239 // These commands scroll the display without changing the RAM
00240 void LCD::scrollDisplayLeft(void) 
00241 {
00242    command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
00243 }
00244 
00245 void LCD::scrollDisplayRight(void) 
00246 {
00247    command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
00248 }
00249 
00250 // This is for text that flows Left to Right
00251 void LCD::leftToRight(void) 
00252 {
00253    _displaymode |= LCD_ENTRYLEFT;
00254    command(LCD_ENTRYMODESET | _displaymode);
00255 }
00256 
00257 // This is for text that flows Right to Left
00258 void LCD::rightToLeft(void) 
00259 {
00260    _displaymode &= ~LCD_ENTRYLEFT;
00261    command(LCD_ENTRYMODESET | _displaymode);
00262 }
00263 
00264 // This method moves the cursor one space to the right
00265 void LCD::moveCursorRight(void)
00266 {
00267    command(LCD_CURSORSHIFT | LCD_CURSORMOVE | LCD_MOVERIGHT);
00268 }
00269 
00270 // This method moves the cursor one space to the left
00271 void LCD::moveCursorLeft(void)
00272 {
00273    command(LCD_CURSORSHIFT | LCD_CURSORMOVE | LCD_MOVELEFT);
00274 }
00275 
00276 
00277 // This will 'right justify' text from the cursor
00278 void LCD::autoscroll(void) 
00279 {
00280    _displaymode |= LCD_ENTRYSHIFTINCREMENT;
00281    command(LCD_ENTRYMODESET | _displaymode);
00282 }
00283 
00284 // This will 'left justify' text from the cursor
00285 void LCD::noAutoscroll(void) 
00286 {
00287    _displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
00288    command(LCD_ENTRYMODESET | _displaymode);
00289 }
00290 
00291 // Write to CGRAM of new characters
00292 void LCD::createChar(uint8_t location, uint8_t charmap[]) 
00293 {
00294    location &= 0x7;            // we only have 8 locations 0-7
00295    
00296    command(LCD_SETCGRAMADDR | (location << 3));
00297    delayMicroseconds(30);
00298    
00299    for (uint8_t i = 0; i < 8; i++)
00300    {
00301       write(charmap[i]);      // call the virtual write method
00302       delayMicroseconds(40);
00303    }
00304 }
00305 
00306 #ifdef __AVR__
00307 void LCD::createChar(uint8_t location, const char *charmap)
00308 {
00309    location &= 0x7;   // we only have 8 memory locations 0-7
00310    
00311    command(LCD_SETCGRAMADDR | (location << 3));
00312    delayMicroseconds(30);
00313    
00314    for (uint8_t i = 0; i < 8; i++)
00315    {
00316       write(pgm_read_byte_near(charmap++));
00317       delayMicroseconds(40);
00318    }
00319 }
00320 #endif // __AVR__
00321 
00322 //
00323 // Switch on the backlight
00324 void LCD::backlight ( void )
00325 {
00326    setBacklight(255);
00327 }
00328 
00329 //
00330 // Switch off the backlight
00331 void LCD::noBacklight ( void )
00332 {
00333    setBacklight(0);
00334 }
00335 
00336 //
00337 // Switch fully on the LCD (backlight and LCD)
00338 void LCD::on ( void )
00339 {
00340    display();
00341    backlight();
00342 }
00343 
00344 //
00345 // Switch fully off the LCD (backlight and LCD) 
00346 void LCD::off ( void )
00347 {
00348    noBacklight();
00349    noDisplay();
00350 }
00351 
00352 // General LCD commands - generic methods used by the rest of the commands
00353 // ---------------------------------------------------------------------------
00354 void LCD::command(uint8_t value) 
00355 {
00356    send(value, COMMAND);
00357 }
00358 
00359 #if (ARDUINO <  100)
00360 void LCD::write(uint8_t value)
00361 {
00362    send(value, DATA);
00363 }
00364 #else
00365 size_t LCD::write(uint8_t value) 
00366 {
00367    send(value, DATA);
00368    return 1;             // assume OK
00369 }
00370 #endif
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