LCD Library 1.1.1
LCD Library - LCD control class hierarchy library. Drop in replacement for the LiquidCrystal Library.
/Users/fmalpartida/development/ardWorkspace/LiquidCrystal_I2C/LiquiCrystal_I2C/LiquidCrystal_SR.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_SR.h
00013 //  Connects an LCD using 2 or 3 pins from the Arduino, via an 8-bit 
00014 // ShiftRegister (SR from now on).
00015 // 
00016 // @brief 
00017 // This is a port of the ShiftRegLCD library from raron and ported to the
00018 // LCD library.
00019 //
00020 // The functionality provided by this class and its base class is identical
00021 // to the original functionality of the Arduino LiquidCrystal library and can
00022 // be used as such.
00023 //
00024 // Modified to work serially with the shiftOut() function, an 8-bit shiftregister 
00025 // (SR) and an LCD in 4-bit mode.
00026 //
00027 // Shiftregister connection description (NEW as of 2009.07.27)
00028 //
00029 // Bit  #0 - N/C - not connected, used to hold a zero
00030 // Bits #1 - N/C
00031 // Bit  #2 - connects to RS (Register Select) on the LCD
00032 // Bits #3 - #6 from SR connects to LCD data inputs D4 - D7.
00033 // Bit  #7 - is used to enabling the enable-puls (via a diode-resistor AND "gate")
00034 //
00035 // 2 or 3 Pins required from the Arduino for Data, Clock, and Enable (optional). 
00036 // If not using Enable, the Data pin is used for the enable signal by defining 
00037 // the same pin for Enable as for Data. Data and Clock outputs/pins goes to the 
00038 // shiftregister.
00039 // LCD RW-pin hardwired to LOW (only writing to LCD). Busy Flag (BF, data bit D7) 
00040 // is not read.
00041 //
00042 // Any shift register should do. I used 74LS164, for the reason that's what I 
00043 // had at hand.
00044 //
00045 //  Original project homepage: http://code.google.com/p/arduinoshiftreglcd/
00046 //
00047 // History
00048 // 2011.10.29  fmalpartida - adaption of the library to the LCD class hierarchy.
00049 // 2009.05.23  raron - but; based mostly (as in almost verbatim) on the 
00050 //             "official" LiquidCrystal library.
00051 // 2009.07.23  Incorporated some proper initialization routines
00052 //             inspired (lets say copy-paste-tweaked) from LiquidCrystal library 
00053 //             improvements from LadyAda
00054 // 2009.07.25  raron - Fixed comments. I really messed up the comments before 
00055 //             posting this, so I had to fix it.
00056 //             Also renamed a function, but no improvements or functional changes.
00057 // 2009.07.27  Thanks to an excellent suggestion from mircho at the Arduiono 
00058 //             playgrond forum, the number of wires now required is only two!
00059 // 2009.07.28  Mircho / raron - a new modification to the schematics, and a more 
00060 //             streamlined interface
00061 // 2009.07.30  raron - minor corrections to the comments. Fixed keyword highlights. 
00062 //             Fixed timing to datasheet safe.
00063 // 2011.07.02  Fixed a minor flaw in setCursor function. No functional change, 
00064 //             just a bit more memory efficient.
00065 //             Thanks to CapnBry (from google code and github) who noticed it. 
00066 //             URL to his version of shiftregLCD:
00067 //https://github.com/CapnBry/HeaterMeter/commit/c6beba1b46b092ab0b33bcbd0a30a201fd1f28c1
00068 //
00069 //
00070 // This library is only compatible with Arduino's SDK version 1.0
00071 //
00072 //
00073 // @author F. Malpartida - fmalpartida@gmail.com
00074 // ---------------------------------------------------------------------------
00075 #include <stdio.h>
00076 #include <string.h>
00077 #include <inttypes.h>
00078 
00079 #if (ARDUINO <  100)
00080 #include <WProgram.h>
00081 #else
00082 #include <Arduino.h>
00083 #endif
00084 #include <LiquidCrystal_SR.h>
00085 
00086 // When the display powers up, it is configured as follows:
00087 //
00088 // 1. Display clear
00089 // 2. Function set: 
00090 //    DL = 1; 8-bit interface data 
00091 //    N = 0; 1-line display 
00092 //    F = 0; 5x8 dot character font 
00093 // 3. Display on/off control: 
00094 //    D = 0; Display off 
00095 //    C = 0; Cursor off 
00096 //    B = 0; Blinking off 
00097 // 4. Entry mode set: 
00098 //    I/D = 1; Increment by 1 
00099 //    S = 0; No shift 
00100 //
00101 // Note, however, that resetting the Arduino doesn't reset the LCD, so we
00102 // can't assume that its in that state when a sketch starts (and the
00103 // LiquidCrystal constructor is called).
00104 // A call to begin() will reinitialize the LCD.
00105 
00106 // STATIC helper routines
00107 // ---------------------------------------------------------------------------
00117 inline static void waitUsec ( uint16_t uSec )
00118 {
00119 #ifndef FAST_MODE
00120    delayMicroseconds ( uSec );
00121 #endif // FAST_MODE
00122 
00123 // CONSTRUCTORS
00124 // ---------------------------------------------------------------------------
00125 // Assuming 1 line 8 pixel high font
00126 LiquidCrystal_SR::LiquidCrystal_SR ( uint8_t srdata, uint8_t srclock, 
00127                                      uint8_t enable ) 
00128 {
00129         init ( srdata, srclock, enable, 1, 0 );
00130 }
00131 // Set nr. of lines, assume 8 pixel high font
00132 LiquidCrystal_SR::LiquidCrystal_SR ( uint8_t srdata, uint8_t srclock, 
00133                                      uint8_t enable, uint8_t lines ) 
00134 {
00135         init ( srdata, srclock, enable, lines, 0 );
00136 }
00137 
00138 // Set nr. of lines and font
00139 LiquidCrystal_SR::LiquidCrystal_SR ( uint8_t srdata, uint8_t srclock, 
00140                                      uint8_t enable, uint8_t lines, 
00141                                      uint8_t font ) 
00142 {
00143         init ( srdata, srclock, enable, lines, font );
00144 }
00145 
00146 
00147 // PRIVATE METHODS
00148 // ---------------------------------------------------------------------------
00149 
00150 //
00151 // init
00152 void LiquidCrystal_SR::init( uint8_t srdata, uint8_t srclock, uint8_t enable, 
00153                              uint8_t lines, uint8_t font )
00154 {
00155    // Initialise private variables
00156    _two_wire    = 0;
00157    _srdata_pin  = srdata; 
00158    _srclock_pin = srclock; 
00159    _enable_pin  = enable;
00160    
00161    if (enable == TWO_WIRE)
00162    {
00163       _enable_pin = _srdata_pin;
00164       _two_wire   = 1;
00165    }
00166    
00167    // Configure control pins as outputs
00168    // ------------------------------------------------------------------------
00169    pinMode(_srclock_pin, OUTPUT);
00170    pinMode(_srdata_pin, OUTPUT);
00171    pinMode(_enable_pin, OUTPUT);
00172    
00173    _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x10DOTS;
00174 }
00175 
00176 // PUBLIC METHODS
00177 // ---------------------------------------------------------------------------
00178 
00179 //
00180 // begin
00181 void LiquidCrystal_SR::begin(uint8_t cols, uint8_t lines, uint8_t dotsize) 
00182 {
00183    
00184    if (lines > 1) 
00185    {
00186       _displayfunction |= LCD_2LINE;
00187    }
00188 
00189    _numlines = lines;
00190    _cols = cols;
00191    
00192    // for some 1 line displays you can select a 10 pixel high font
00193    // ------------------------------------------------------------
00194    if ((dotsize != 0) && (lines == 1)) 
00195    {
00196       _displayfunction |= LCD_5x10DOTS;
00197    }
00198    
00199    // SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
00200    // according to datasheet, we need at least 40ms after power rises above 2.7V
00201    // before sending commands. Arduino can turn on way before 4.5V so we'll wait 
00202    // 50
00203    // ---------------------------------------------------------------------------
00204    delayMicroseconds(50000);
00205    init4bits(LCD_FUNCTIONSET | LCD_8BITMODE);
00206    delayMicroseconds(4500);  // wait more than 4.1ms
00207    
00208    // Second try
00209    init4bits(LCD_FUNCTIONSET | LCD_8BITMODE);
00210    delayMicroseconds(150);
00211    // Third go
00212    init4bits(LCD_FUNCTIONSET | LCD_8BITMODE);
00213    
00214    // And finally, set to 4-bit interface
00215    init4bits(LCD_FUNCTIONSET | LCD_4BITMODE);
00216    
00217    // Set # lines, font size, etc.
00218    command(LCD_FUNCTIONSET | _displayfunction);
00219    // Turn the display on with no cursor or blinking default
00220    _displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;
00221    display();
00222    // Clear it off
00223    clear();
00224    // Initialize to default text direction (for romance languages)
00225    _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
00226    // set the entry mode
00227    command(LCD_ENTRYMODESET | _displaymode);
00228    home();
00229    
00230 }
00231 
00232 /************ low level data pushing commands **********/
00233 
00234 // send
00235 void LiquidCrystal_SR::send(uint8_t value, uint8_t mode) 
00236 {
00237    uint8_t val1, val2;
00238    
00239    // If _two_wire - clear the shiftregister first.
00240    // ----------------------------------------------
00241    if ( _two_wire ) 
00242    {
00243       shiftOut ( _srdata_pin, _srclock_pin, MSBFIRST, 0x00 );
00244    }
00245    digitalWrite( _enable_pin, LOW );
00246    
00247    mode = mode ? SR_RS_BIT : 0; // RS bit; LOW: command.  HIGH: character.
00248    val1 = mode | SR_EN_BIT | ((value >> 1) & 0x78); // upper nibble
00249    val2 = mode | SR_EN_BIT | ((value << 3) & 0x78); // lower nibble
00250    
00251    shiftOut ( _srdata_pin, _srclock_pin, MSBFIRST, val1 );
00252    
00253    digitalWrite( _enable_pin, HIGH );
00254    waitUsec( 1 );                 // enable pulse must be >450ns
00255    digitalWrite( _enable_pin, LOW );
00256 
00257    // clear shiftregister
00258    // ---------------------------
00259    if ( _two_wire ) 
00260    {
00261       shiftOut ( _srdata_pin, _srclock_pin, MSBFIRST, 0x00 ); 
00262    }
00263    shiftOut ( _srdata_pin, _srclock_pin, MSBFIRST, val2 );
00264    
00265    digitalWrite( _enable_pin, HIGH );
00266    waitUsec( 1 );                 // enable pulse must be >450ns
00267    digitalWrite( _enable_pin, LOW );
00268    waitUsec( 40 );                // commands need > 37us to settle
00269 }
00270 
00271 //
00272 // init4bits
00273 void LiquidCrystal_SR::init4bits(uint8_t value) 
00274 {
00275    uint8_t val1;
00276    
00277    // clear shiftregister
00278    // --------------------------
00279    if ( _two_wire ) 
00280    {
00281       shiftOut ( _srdata_pin, _srclock_pin, MSBFIRST, 0x00 ); 
00282    }
00283    digitalWrite( _enable_pin, LOW );
00284    
00285    val1 = SR_EN_BIT | ((value >> 1) & 0x78);
00286    shiftOut ( _srdata_pin, _srclock_pin, MSBFIRST, val1 );
00287    
00288    digitalWrite( _enable_pin, HIGH );
00289    waitUsec( 1 );                 // enable pulse must be >450ns
00290    digitalWrite( _enable_pin, LOW );
00291    
00292    waitUsec( 40 );               // commands need > 37us to settle
00293 }
00294 
00295 
00296 
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