![]() |
LCD Library 1.3.0
LCD Library - LCD control class hierarchy library. Drop in replacement for the LiquidCrystal Library.
|
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 // 2012.03.29 bperrybap - Added delays for faster fio shiftout (it got too fast) 00051 // AVR needed delay. cmd/write delays are based on CPU speed so it works on pic32. 00052 // Added code to support indicating two wire mode by using enable=data pin 00053 // (documentation indicated this as working) 00054 // Fixed incorrect use of 5x10 for default font - now matches original LQ library. 00055 // can now eliminate enable pin in constructor for two wire mode. 00056 // 2012.01.16 Florian Fida - faster digitalWrite/shiftOut 00057 // 2011.10.29 fmalpartida - adaption of the library to the LCD class hierarchy. 00058 // 2011.07.02 Fixed a minor flaw in setCursor function. No functional change, 00059 // just a bit more memory efficient. 00060 // Thanks to CapnBry (from google code and github) who noticed it. 00061 // URL to his version of shiftregLCD: 00062 // https://github.com/CapnBry/HeaterMeter/commit/c6beba1b46b092ab0b33bcbd0a30a201fd1f28c1 00063 // 2009.07.30 raron - minor corrections to the comments. 00064 // Fixed timing to datasheet safe. Fixed keyword highlights. 00065 // 2009.07.28 Mircho / raron - a new modification to the schematics, and a 00066 // more streamlined interface 00067 // 2009.07.27 Thanks to an excellent suggestion from mircho at the Arduino 00068 // playgrond forum, the number of wires now required is only two! 00069 // 2009.07.25 raron - Fixed comments. I really messed up the comments before 00070 // posting this, so I had to fix it. 00071 // Renamed a function, but no improvements or functional changes. 00072 // 2009.07.23 Incorporated some proper initialization routines 00073 // inspired (lets say copy-paste-tweaked) from LiquidCrystal 00074 // library improvements from LadyAda. 00075 // 2009.05.23 raron - first version, but based mostly (as in almost verbatim) 00076 // on the "official" LiquidCrystal library. 00077 // 00078 // 00079 // @author F. Malpartida - fmalpartida@gmail.com 00080 // --------------------------------------------------------------------------- 00081 #include <stdio.h> 00082 #include <string.h> 00083 #include <inttypes.h> 00084 00085 #if (ARDUINO < 100) 00086 #include <WProgram.h> 00087 #else 00088 #include <Arduino.h> 00089 #endif 00090 #include "LiquidCrystal_SR.h" 00091 00092 #include "FastIO.h" 00093 00094 00095 // CONSTRUCTORS 00096 // --------------------------------------------------------------------------- 00097 // Assuming 1 line 8 pixel high font 00098 LiquidCrystal_SR::LiquidCrystal_SR (uint8_t srdata, uint8_t srclock, 00099 uint8_t enable ) 00100 { 00101 init ( srdata, srclock, enable, 1, 0 ); 00102 } 00103 00104 00105 // PRIVATE METHODS 00106 // --------------------------------------------------------------------------- 00107 00108 // 00109 // init 00110 void LiquidCrystal_SR::init(uint8_t srdata, uint8_t srclock, uint8_t enable, 00111 uint8_t lines, uint8_t font) 00112 { 00113 // Initialise private variables 00114 _two_wire = 0; 00115 00116 _srDataRegister = fio_pinToOutputRegister(srdata); 00117 _srDataBit = fio_pinToBit(srdata); 00118 _srClockRegister = fio_pinToOutputRegister(srclock); 00119 _srClockBit = fio_pinToBit(srclock); 00120 00121 if ((enable == TWO_WIRE) || (enable == srdata)) 00122 { 00123 _two_wire = 1; 00124 _srEnableRegister = _srDataRegister; 00125 _srEnableBit = _srDataBit; 00126 } 00127 else 00128 { 00129 _srEnableRegister = fio_pinToOutputRegister(enable); 00130 _srEnableBit = fio_pinToBit(enable); 00131 } 00132 00133 // Configure control pins as outputs 00134 // ------------------------------------------------------------------------ 00135 00136 _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS; 00137 } 00138 00139 // 00140 // shiftIt 00141 void LiquidCrystal_SR::shiftIt(uint8_t val) 00142 { 00143 if (_two_wire) 00144 { 00145 // Clear to get Enable LOW 00146 fio_shiftOut(_srDataRegister, _srDataBit, _srClockRegister, _srClockBit); 00147 } 00148 fio_shiftOut(_srDataRegister, _srDataBit, _srClockRegister, _srClockBit, val, MSBFIRST); 00149 00150 // LCD ENABLE PULSE 00151 // 00152 // While this library is written with a shift register without an output 00153 // latch in mind, it can work in 3-wire mode with a shiftregister with a 00154 // latch. The shiftregister latch pin (STR, RCL or similar) is then 00155 // connected to the LCD enable pin. The LCD is (very likely) slower 00156 // to read the Enable pulse, and then reads the new contents of the SR. 00157 ATOMIC_BLOCK(ATOMIC_RESTORESTATE) 00158 { 00159 fio_digitalWrite_HIGH(_srEnableRegister, _srEnableBit); 00160 delayMicroseconds (1); // enable pulse must be >450ns 00161 fio_digitalWrite_SWITCHTO(_srEnableRegister, _srEnableBit, LOW); 00162 } // end critical section 00163 } 00164 00165 // PUBLIC METHODS 00166 // --------------------------------------------------------------------------- 00167 00168 00169 /************ low level data pushing commands **********/ 00170 // 00171 // send 00172 void LiquidCrystal_SR::send(uint8_t value, uint8_t mode) 00173 { 00174 // Divide byte in two nibbles include the RS signal 00175 // and format it for shiftregister output wiring to the LCD 00176 // We are only interested in my COMMAND or DATA for myMode 00177 uint8_t myMode = ( mode == DATA ) ? SR_RS_BIT : 0; // RS bit; LOW: command. HIGH: character. 00178 00179 if ( mode != FOUR_BITS ) 00180 { 00181 shiftIt(myMode | SR_EN_BIT | ((value >> 1) & 0x78)); // upper nibble 00182 } 00183 00184 shiftIt(myMode | SR_EN_BIT | ((value << 3) & 0x78)); // lower nibble 00185 /* 00186 * Add some delay since this code is so fast it needs some added delay 00187 * even on AVRs because the shiftout is shorter than the LCD command execution time. 00188 */ 00189 #if (F_CPU <= 16000000) 00190 if(_two_wire) 00191 delayMicroseconds ( 10 ); 00192 else 00193 delayMicroseconds ( 17 ); // 3 wire mode is faster so it must delay longer 00194 #else 00195 delayMicroseconds ( 37 ); // commands & data writes need > 37us to complete 00196 #endif 00197 00198 } 00199 00200 // 00201 // setBacklightPin 00202 void LiquidCrystal_SR::setBacklightPin ( uint8_t pin, t_backlighPol pol ) 00203 { } 00204 00205 // 00206 // setBacklight 00207 void LiquidCrystal_SR::setBacklight ( uint8_t mode ) 00208 { } 00209