LCD Library: LiquidCrystal_SR3W.cpp Source File

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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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