LCD Library 1.2.1
LCD Library - LCD control class hierarchy library. Drop in replacement for the LiquidCrystal Library.
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00001 // ---------------------------------------------------------------------------
00002 // Created/Adapted by Bill Perry 2012-03-16
00003 // Copyright 2012 - 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_SR2W.cpp
00013 // Connects a hd44780 LCD using 2 pins from the Arduino, via an 8-bit 
00014 // ShiftRegister (SR2W 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 //
00021 // See the corresponding SR2W header file for full details.
00022 //
00023 // History
00024 // 2012.03.29  bperrybap - Fixed incorrect use of 5x10 for default font 
00025 //                         (now matches original LQ library)
00026 //                         Fixed typo in SR2W mask define names
00027 //                         changed default backlight state to on
00028 // 2012.03.16  bperrybap - created/modified from SR sources to create SR2W
00029 // @author B. Perry - bperrybap@opensource.billsworld.billandterrie.com
00030 // ---------------------------------------------------------------------------
00031 
00032 #include "LiquidCrystal_SR2W.h"
00033 
00034 // CONSTRUCTORS
00035 // ---------------------------------------------------------------------------
00036 // Assuming 1 line 8 pixel high font
00037 LiquidCrystal_SR2W::LiquidCrystal_SR2W (uint8_t srdata, uint8_t srclock, t_backlighPol blpol)
00038 {
00039         init ( srdata, srclock, blpol, 1, 0 );
00040 }
00041 
00042 
00043 // PRIVATE METHODS
00044 // ---------------------------------------------------------------------------
00045 
00046 //
00047 // init
00048 void LiquidCrystal_SR2W::init(uint8_t srdata, uint8_t srclock, t_backlighPol blpol, uint8_t lines, uint8_t font)
00049 {
00050         _srDataRegister = fio_pinToOutputRegister(srdata);
00051         _srDataMask = fio_pinToBit(srdata);
00052         _srClockRegister = fio_pinToOutputRegister(srclock);
00053         _srClockMask = fio_pinToBit(srclock);
00054    
00055         _blPolarity = blpol;
00056    
00057         _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
00058    
00059         backlight(); // set default backlight state to on
00060 }
00061 
00062 //
00063 // loadSR
00064 void LiquidCrystal_SR2W::loadSR(uint8_t val)
00065 {
00066         // Clear to keep Enable LOW while clocking in new bits
00067         fio_shiftOut(_srDataRegister, _srDataMask, _srClockRegister, _srClockMask);
00068    
00069    
00070         // clock out SR data byte
00071         fio_shiftOut(_srDataRegister, _srDataMask, _srClockRegister, _srClockMask, val, MSBFIRST);
00072    
00073         
00074         // strobe LCD enable which can now be toggled by the data line
00075         ATOMIC_BLOCK(ATOMIC_RESTORESTATE)
00076         {
00077                 fio_digitalWrite_HIGH(_srDataRegister, _srDataMask);
00078                 waitUsec (1);         // enable pulse must be >450ns               
00079                 fio_digitalWrite_SWITCHTO(_srDataRegister, _srDataMask, LOW);
00080         } // end critical section
00081 }
00082 
00083 // PUBLIC METHODS
00084 // ---------------------------------------------------------------------------
00085 
00086 
00087 /************ low level data pushing commands **********/
00088 //
00089 // send
00090 void LiquidCrystal_SR2W::send(uint8_t value, uint8_t mode)
00091 {
00092         uint8_t myMode = ( mode == DATA ) ? SR2W_RS_MASK : 0; 
00093    
00094         myMode = myMode | SR2W_EN_MASK | _blMask;
00095 
00096         if ( mode != FOUR_BITS )
00097         {
00098                 loadSR(myMode | ((value >> 1) & SR2W_DATA_MASK)); // upper nibble
00099         }
00100 
00101         loadSR(myMode | ((value << 3) & SR2W_DATA_MASK)); // lower nibble
00102    
00103         /*
00104          * Don't call waitUsec()
00105          * do our own delay optmization since this code is so fast it needs some added delay
00106          * even on slower AVRs.
00107          */
00108 #if (F_CPU <= 16000000)
00109         delayMicroseconds ( 10 );      // commands & data writes need > 37us to complete
00110 #else
00111         delayMicroseconds ( 37 );      // commands & data writes need > 37us to complete
00112 #endif
00113 }
00114 
00115 //
00116 // setBacklight
00117 void LiquidCrystal_SR2W::setBacklight ( uint8_t value ) 
00118 { 
00119         // Check for polarity to configure mask accordingly
00120         // ----------------------------------------------------------
00121         if  ( ((_blPolarity == POSITIVE) && (value > 0)) || 
00122         ((_blPolarity == NEGATIVE ) && ( value == 0 )) )
00123         {
00124                 _blMask = SR2W_BL_MASK;
00125         }
00126         else 
00127         {
00128                 _blMask = 0;
00129         }
00130    
00131         // send dummy data of blMask to set BL pin
00132         // Note: loadSR() will strobe the data line trying to pulse EN
00133         // but E will not strobe because the EN output bit is not set.
00134         loadSR(_blMask); 
00135 }
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