LCD Library 1.2.1
LCD Library - LCD control class hierarchy library. Drop in replacement for the LiquidCrystal Library.
/Users/fmalpartida/development/ardWorkspace/LiquidCrystal_I2C/LiquiCrystal_I2C/LiquidCrystal_SR3W.cpp
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00001 // ---------------------------------------------------------------------------
00002 // Created by Francisco Malpartida on 7.3.2012.
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_SRG.h
00013 // This file implements a basic liquid crystal library that comes as standard
00014 // in the Arduino SDK but using a generic SHIFT REGISTER 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 a 3 wire latching
00021 // shift register. While it has been tested with a 74HC595N shift register
00022 // it should also work with other latching shift registers such as the MC14094
00023 // and the HEF4094
00024 //
00025 // This particular driver has been created as generic as possible to enable
00026 // users to configure and connect their LCDs using just 3 digital IOs from the
00027 // AVR or Arduino, and connect the LCD to the outputs of the shiftregister
00028 // in any configuration. The library is configured by passing the IO pins
00029 // that control the strobe, data and clock of the shift register and a map
00030 // of how the shiftregister is connected to the LCD.
00031 // 
00032 //
00033 //   +--------------------------------------------+
00034 //   |                 MCU                        |
00035 //   |   IO1           IO2           IO3          |
00036 //   +----+-------------+-------------+-----------+
00037 //        |             |             |
00038 //        |             |             |
00039 //   +----+-------------+-------------+-----------+
00040 //   |    Strobe        Data          Clock       |
00041 //   |          8-bit shift/latch register        | 74HC595N
00042 //   |    Qa0  Qb1  Qc2  Qd3  Qe4  Qf5  Qg6  Qh7  |
00043 //   +----+----+----+----+----+----+----+----+----+
00044 //        |    |    |    |    |    |    |    
00045 //        |11  |12  |13  |14  |6   |5   |4   (LCD pins)
00046 //   +----+----+----+----+----+----+----+----+----+
00047 //   |    DB4  DB5  DB6  DB7  E    Rw   RS        |
00048 //   |                 LCD Module                 |
00049 //
00050 // NOTE: Rw is not used by the driver so it can be connected to GND.
00051 //
00052 // The functionality provided by this class and its base class is identical
00053 // to the original functionality of the Arduino LiquidCrystal library.
00054 //
00055 //
00056 // History
00057 // 2012.03.29 bperrybap - fixed constructors not properly using Rs
00058 //                        Fixed incorrect use of 5x10 for default font 
00059 //                        - now matches original LQ library.
00060 //                        moved delay to send() so it is per cmd/write vs shiftout()
00061 //                        NOTE: delay is on hairy edge of working when FAST_MODE is on.
00062 //                        because of waitUsec().
00063 //                        There is margin at 16Mhz AVR but might fail on 20Mhz AVRs.
00064 //                        
00065 // @author F. Malpartida - fmalpartida@gmail.com
00066 // ---------------------------------------------------------------------------
00067 // flags for backlight control
00068 #include <stdio.h>
00069 #include <string.h>
00070 #include <inttypes.h>
00071 
00072 #if (ARDUINO <  100)
00073 #include <WProgram.h>
00074 #else
00075 #include <Arduino.h>
00076 #endif
00077 #include "LiquidCrystal_SR3W.h"
00078 
00079 #include "FastIO.h"
00080 
00086 #define LCD_NOBACKLIGHT 0x00
00087 
00093 #define LCD_BACKLIGHT   0xFF
00094 
00095 
00096 // Default library configuration parameters used by class constructor with
00097 // only the I2C address field.
00098 // ---------------------------------------------------------------------------
00104 #define EN 4  // Enable bit
00105 
00111 #define RW 5  // Read/Write bit
00112 
00118 #define RS 6  // Register select bit
00119 
00126 #define D4 0
00127 #define D5 1
00128 #define D6 2
00129 #define D7 3
00130 
00131 
00132 
00133 LiquidCrystal_SR3W::LiquidCrystal_SR3W(uint8_t data, uint8_t clk, uint8_t strobe)
00134 {
00135    init( data, clk, strobe, RS, RW, EN, D4, D5, D6, D7 );
00136 }
00137 
00138 LiquidCrystal_SR3W::LiquidCrystal_SR3W(uint8_t data, uint8_t clk, uint8_t strobe,
00139                                        uint8_t backlighPin, t_backlighPol pol)
00140 {
00141    init( data, clk, strobe, RS, RW, EN, D4, D5, D6, D7 );
00142    setBacklightPin(backlighPin, pol);
00143 }
00144 
00145 LiquidCrystal_SR3W::LiquidCrystal_SR3W(uint8_t data, uint8_t clk, uint8_t strobe,
00146                                        uint8_t En, uint8_t Rw, uint8_t Rs, 
00147                                        uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7 )
00148 {
00149    init( data, clk, strobe, Rs, Rw, En, d4, d5, d6, d7 );
00150 }
00151 
00152 LiquidCrystal_SR3W::LiquidCrystal_SR3W(uint8_t data, uint8_t clk, uint8_t strobe, 
00153                                        uint8_t En, uint8_t Rw, uint8_t Rs, 
00154                                        uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7,
00155                                        uint8_t backlighPin, t_backlighPol pol)
00156 {
00157    init( data, clk, strobe, Rs, Rw, En, d4, d5, d6, d7 );
00158    setBacklightPin(backlighPin, pol);
00159 }
00160 
00161 
00162 void LiquidCrystal_SR3W::send(uint8_t value, uint8_t mode)
00163 {
00164    
00165    if ( mode != FOUR_BITS )
00166    {
00167       write4bits( (value >> 4), mode ); // upper nibble
00168    }   
00169    write4bits( (value & 0x0F), mode); // lower nibble
00170 
00171 
00172 #if (F_CPU <= 16000000)
00173    // No need to use the delay routines on AVR since the time taken to write
00174    // on AVR with SR pin mapping even with fio is longer than LCD command execution.
00175    waitUsec(37); //goes away on AVRs
00176 #else
00177    delayMicroseconds ( 37 );      // commands & data writes need > 37us to complete
00178 #endif
00179 
00180 }
00181 
00182 
00183 void LiquidCrystal_SR3W::setBacklightPin ( uint8_t value, t_backlighPol pol = POSITIVE )
00184 {
00185    _backlightPinMask = ( 1 << value );
00186    _backlightStsMask = LCD_NOBACKLIGHT;
00187    _polarity = pol;
00188    setBacklight (BACKLIGHT_OFF);     // Set backlight to off as initial setup
00189 }
00190 
00191 void LiquidCrystal_SR3W::setBacklight ( uint8_t value )
00192 {
00193    // Check if backlight is available
00194    // ----------------------------------------------------
00195    if ( _backlightPinMask != 0x0 )
00196    {
00197       // Check for polarity to configure mask accordingly
00198       // ----------------------------------------------------------
00199       if  (((_polarity == POSITIVE) && (value > 0)) || 
00200            ((_polarity == NEGATIVE ) && ( value == 0 )))
00201       {
00202          _backlightStsMask = _backlightPinMask & LCD_BACKLIGHT;
00203       }
00204       else 
00205       {
00206          _backlightStsMask = _backlightPinMask & LCD_NOBACKLIGHT;
00207       }
00208       loadSR( _backlightStsMask );
00209    }
00210 }
00211 
00212 
00213 // PRIVATE METHODS
00214 // -----------------------------------------------------------------------------
00215 
00216 int LiquidCrystal_SR3W::init(uint8_t data, uint8_t clk, uint8_t strobe, 
00217                              uint8_t Rs, uint8_t Rw, uint8_t En,
00218                              uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
00219 {
00220    _data       = fio_pinToBit(data);
00221    _clk        = fio_pinToBit(clk);
00222    _strobe     = fio_pinToBit(strobe);
00223    _data_reg   = fio_pinToOutputRegister(data);
00224    _clk_reg    = fio_pinToOutputRegister(clk);
00225    _strobe_reg = fio_pinToOutputRegister(strobe);
00226    
00227    // LCD pin mapping
00228    _backlightPinMask = 0;
00229    _backlightStsMask = LCD_NOBACKLIGHT;
00230    _polarity = POSITIVE;
00231    
00232    _En = ( 1 << En );
00233    _Rw = ( 1 << Rw );
00234    _Rs = ( 1 << Rs );
00235    
00236    // Initialise pin mapping
00237    _data_pins[0] = ( 1 << d4 );
00238    _data_pins[1] = ( 1 << d5 );
00239    _data_pins[2] = ( 1 << d6 );
00240    _data_pins[3] = ( 1 << d7 );
00241    
00242    _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
00243    
00244    return (1);
00245 }
00246 
00247 void LiquidCrystal_SR3W::write4bits(uint8_t value, uint8_t mode)
00248 {
00249    uint8_t pinMapValue = 0;
00250    
00251    // Map the value to LCD pin mapping
00252    // --------------------------------
00253    for ( uint8_t i = 0; i < 4; i++ )
00254    {
00255       if ( ( value & 0x1 ) == 1 )
00256       {
00257          pinMapValue |= _data_pins[i];
00258       }
00259       value = ( value >> 1 );
00260    }
00261    
00262    // Is it a command or data
00263    // -----------------------
00264    mode = ( mode == DATA ) ? _Rs : 0;
00265    
00266    pinMapValue |= mode | _backlightStsMask;
00267    loadSR ( pinMapValue | _En );  // Send with enable high
00268    loadSR ( pinMapValue); // Send with enable low
00269 }
00270 
00271 
00272 void LiquidCrystal_SR3W::loadSR(uint8_t value) 
00273 {
00274    // Load the shift register with information
00275    fio_shiftOut(_data_reg, _data, _clk_reg, _clk, value, MSBFIRST);
00276    
00277    // Strobe the data into the latch
00278    ATOMIC_BLOCK(ATOMIC_RESTORESTATE)
00279    {
00280       fio_digitalWrite_HIGH(_strobe_reg, _strobe);
00281       fio_digitalWrite_SWITCHTO(_strobe_reg, _strobe, LOW);
00282    }
00283 }
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