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LCD Library 1.2.0
LCD Library - LCD control class hierarchy library. Drop in replacement for the LiquidCrystal Library.
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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 00025 // unlatched, no-tristate, unidirectional SIPO (Serial-In-Parallel-Out) 00026 // shift register (IE a very simple SR), and an LCD in 4-bit mode. 00027 // Any such shift register should do (pref. 74LS family IC's for 2-wire). 00028 // I used 74LS164, for the reason that's what I had at hand. 00029 // 00030 // Connection description: 00031 // 00032 // SR output: 00033 // Bit #0 - N/C - not connected, used to hold a zero 00034 // Bit #1 - N/C 00035 // Bit #2 - connects to RS (Register Select) on the LCD 00036 // Bits #3-6 - connects to LCD data inputs D4 - D7. 00037 // Bit #7 - enables the LCD enable-puls (via the diode-resistor AND "gate") 00038 // 00039 // 2 or 3 Pins required from the Arduino for Data, Clock and (optional) Enable 00040 // If not using Enable, the Data pin is used for the enable signal by defining 00041 // the same pin for Enable as for Data. Data and Clock outputs/pins goes to 00042 // the shiftregister. 00043 // LCD RW-pin hardwired to LOW (only writing to LCD). 00044 // Busy Flag (BF, data bit D7) is not read. 00045 // 00046 // Original project homepage: http://code.google.com/p/arduinoshiftreglcd/ 00047 // 00048 // 00049 // History 00050 // 2012.01.16 Florian Fida - faster digitalWrite/shiftOut 00051 // 2011.10.29 fmalpartida - adaption of the library to the LCD class hierarchy. 00052 // 2011.07.02 Fixed a minor flaw in setCursor function. No functional change, 00053 // just a bit more memory efficient. 00054 // Thanks to CapnBry (from google code and github) who noticed it. 00055 // URL to his version of shiftregLCD: 00056 // https://github.com/CapnBry/HeaterMeter/commit/c6beba1b46b092ab0b33bcbd0a30a201fd1f28c1 00057 // 2009.07.30 raron - minor corrections to the comments. 00058 // Fixed timing to datasheet safe. Fixed keyword highlights. 00059 // 2009.07.28 Mircho / raron - a new modification to the schematics, and a 00060 // more streamlined interface 00061 // 2009.07.27 Thanks to an excellent suggestion from mircho at the Arduino 00062 // playgrond forum, the number of wires now required is only two! 00063 // 2009.07.25 raron - Fixed comments. I really messed up the comments before 00064 // posting this, so I had to fix it. 00065 // Renamed a function, but no improvements or functional changes. 00066 // 2009.07.23 Incorporated some proper initialization routines 00067 // inspired (lets say copy-paste-tweaked) from LiquidCrystal 00068 // library improvements from LadyAda. 00069 // 2009.05.23 raron - first version, but based mostly (as in almost verbatim) 00070 // on the "official" LiquidCrystal library. 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 #include "FastIO.h" 00087 00088 00089 // CONSTRUCTORS 00090 // --------------------------------------------------------------------------- 00091 // Assuming 1 line 8 pixel high font 00092 LiquidCrystal_SR::LiquidCrystal_SR ( uint8_t srdata, uint8_t srclock, 00093 uint8_t enable ) 00094 { 00095 init ( srdata, srclock, enable, 1, 0 ); 00096 } 00097 00098 00099 // PRIVATE METHODS 00100 // --------------------------------------------------------------------------- 00101 00102 // 00103 // init 00104 void LiquidCrystal_SR::init(uint8_t srdata, uint8_t srclock, uint8_t enable, uint8_t lines, uint8_t font) 00105 { 00106 // Initialise private variables 00107 _two_wire = 0; 00108 00109 _srDataRegister = fio_pinToOutputRegister(srdata); 00110 _srDataBit = fio_pinToBit(srdata); 00111 _srClockRegister = fio_pinToOutputRegister(srclock); 00112 _srClockBit = fio_pinToBit(srclock); 00113 00114 if (enable == TWO_WIRE) 00115 { 00116 _two_wire = 1; 00117 _srEnableRegister = _srDataRegister; 00118 _srEnableBit = _srDataBit; 00119 } 00120 else 00121 { 00122 _srEnableRegister = fio_pinToOutputRegister(enable); 00123 _srEnableBit = fio_pinToBit(enable); 00124 } 00125 00126 // Configure control pins as outputs 00127 // ------------------------------------------------------------------------ 00128 00129 _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x10DOTS; 00130 } 00131 00132 // shiftIt 00133 void LiquidCrystal_SR::shiftIt(uint8_t val) 00134 { 00135 if (_two_wire) 00136 { 00137 // Clear to get Enable LOW 00138 fio_shiftOut(_srDataRegister, _srDataBit, _srClockRegister, _srClockBit); 00139 } 00140 fio_shiftOut(_srDataRegister, _srDataBit, _srClockRegister, _srClockBit, val, MSBFIRST); 00141 00142 // LCD ENABLE PULSE 00143 // 00144 // While this library is written with a shift register without an output 00145 // latch in mind, it can work in 3-wire mode with a shiftregister with a 00146 // latch. The shiftregister latch pin (STR, RCL or similar) is then 00147 // connected to the LCD enable pin. The LCD is (very likely) slower 00148 // to read the Enable pulse, and then reads the new contents of the SR. 00149 fio_digitalWrite_HIGH(_srEnableRegister, _srEnableBit); 00150 waitUsec (1); // enable pulse must be >450ns 00151 fio_digitalWrite_SWITCHTO(_srEnableRegister, _srEnableBit, LOW); 00152 waitUsec ( 37 ); // commands need > 37us to settle 00153 } 00154 00155 // PUBLIC METHODS 00156 // --------------------------------------------------------------------------- 00157 00158 00159 /************ low level data pushing commands **********/ 00160 00161 // send 00162 void LiquidCrystal_SR::send(uint8_t value, uint8_t mode) 00163 { 00164 // Divide byte in two nibbles include the RS signal 00165 // and format it for shiftregister output wiring to the LCD 00166 mode = mode ? SR_RS_BIT : 0; // RS bit; LOW: command. HIGH: character. 00167 shiftIt(mode | SR_EN_BIT | ((value >> 1) & 0x78)); // upper nibble 00168 shiftIt(mode | SR_EN_BIT | ((value << 3) & 0x78)); // lower nibble 00169 } 00170 00171 // 00172 // setBacklight 00173 void LiquidCrystal_SR::setBacklight ( uint8_t mode ) 00174 { } 00175 00176 00177 void LiquidCrystal_SR::setBacklightPin ( uint8_t pin ) 00178 { }