NewTextLCD.cpp

00001 /* mbed TextLCD Library, for a 4-bit LCD based on HD44780
00002  * Copyright (c) 2007-2010, sford, http://mbed.org
00003  * Changes by Erik Kerger
00004  *
00005  *
00006  * Permission is hereby granted, free of charge, to any person obtaining a copy
00007  * of this software and associated documentation files (the "Software"), to deal
00008  * in the Software without restriction, including without limitation the rights
00009  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00010  * copies of the Software, and to permit persons to whom the Software is
00011  * furnished to do so, subject to the following conditions:
00012  *
00013  * The above copyright notice and this permission notice shall be included in
00014  * all copies or substantial portions of the Software.
00015  *
00016  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00017  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00018  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00019  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00020  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00021  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00022  * THE SOFTWARE.
00023  */
00024 
00025 #include "NewTextLCD.h"
00026 #include "mbed.h"
00027 
00028 TextLCD::TextLCD(PinName rs, PinName rw, PinName e, PinName d4, PinName d5,
00029                  PinName d6, PinName d7, LCDType type) : _rs(rs), _rw(rw), _e(e), 
00030                     _d(d4, d5, d6, d7), _type(type) {
00031     _rs = 0;            // command mode
00032     _rw = 0;            // r/w in defined state
00033     _e  = 0;            // 0 --> inactive (most important change to original TextLCD)
00034     
00035     if (_type != LCDuser)
00036         setLCDparam(_type); // otherwise rows, colums, comdelay, adresses must be set before
00037 
00038     wait(0.050f);       // Wait 50ms to ensure powered up
00039 
00040     // send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
00041     // this sets controler into 8 bit mode, so we have a defined state
00042     for (int i=0; i<3; i++) {
00043         _e = 1;
00044         __nop();
00045         __nop();
00046         _d = 0x3;
00047         __nop();        // data setup time at least 60 ns
00048         _e = 0;
00049         wait(0.005f);   // 5ms
00050        }
00051     _e = 1;
00052     __nop();
00053     __nop();
00054     _d = 0x2;           // 4 Bit mode (after this command, we have to send 2 nibbles)
00055     __nop(); 
00056     _e = 0;
00057     wait_us(LCDparam.delay);
00058     
00059     writeCommand(0x28); // Function set 4 Bit, 2Line, 5*7
00060     writeCommand(0x08); // Display off
00061     cls();              // clear display, reset _column and _row
00062     writeCommand(0x04); // cursor right, Display is not shifted
00063     writeCommand(0x0C); // Display on , Cursor off 
00064 }
00065 
00066 void TextLCD::character(int column, int row, int c) {
00067     int a = 0x80 | (LCDparam.adresses[row & 3] + column);
00068     writeCommand(a);    // set cursor address
00069     writeData(c);       // write char
00070 }
00071 
00072 void TextLCD::cls() {
00073     writeCommand(0x01); // cls, and set cursor to 0
00074     locate(0, 0);       // set internal position
00075     wait_us(45 * LCDparam.delay);   // CLS need much time
00076 }
00077 
00078 void TextLCD::locate(int column, int row) {
00079     _column = column;   // set position for next char
00080     _row = row;         // note: cursor is not set yet
00081 }
00082 
00083 
00084 
00085 int TextLCD::_putc(int value) {
00086     if (value == '\n') {
00087         _column = 0;
00088         _row++;
00089         if (_row >= LCDparam.rows) {
00090             _row = 0;
00091         }
00092     } else {
00093         character(_column, _row, value);
00094         _column++;
00095         if (_column >= LCDparam.columns) {
00096             _column = 0;
00097             _row++;
00098             if (_row >= LCDparam.rows) {
00099                 _row = 0;
00100             }
00101         }
00102     }
00103     return value;
00104 }
00105 
00106 // Dummy function - read not supported
00107 int TextLCD::_getc() {
00108     return -1;
00109 }
00110 
00111 void TextLCD::writeByte(int value) {
00112     _e = 1;
00113     __nop();    
00114     _d = value >> 4;        // higher nibble first
00115     __nop();
00116     _e = 0;
00117     __nop();
00118     __nop();
00119     _e = 1;
00120     __nop();
00121     _d = value >> 0;        // then lower
00122     __nop();
00123     _e = 0;
00124 }
00125 
00126 void TextLCD::writeCommand(int command) {
00127     _rs = 0;
00128     writeByte(command);
00129     wait_us(LCDparam.delay);
00130 }
00131 
00132 
00133 void TextLCD::writeData(int data) {
00134     _rs = 1;
00135     writeByte(data);
00136     wait_us(LCDparam.delay);
00137 }
00138 
00139 
00140 // set user defined char 
00141 void  TextLCD::writeCGRAM(int address, int pattern[8]){
00142     int i;
00143     address = address & 7;  //max 8 char
00144     for(i=0;i<8;i++){
00145         writeCommand(0x40 | (address * 8) + i);
00146         writeData(pattern[i]);
00147         }
00148 }   
00149 
00150 void TextLCD::setLCDparam(LCDType _type){
00151     switch (_type) {
00152     
00153         case LCD16x2:
00154         case LCD16x2B:
00155             LCDparam.columns = 16;
00156             break;
00157         case LCD20x2:
00158         case LCD20x4:
00159             LCDparam.columns = 20;
00160             break;
00161         case LCD24x2:
00162             LCDparam.columns = 24;
00163             break;
00164     }
00165     if (_type == LCD20x4) 
00166         LCDparam.rows = 4;
00167     else 
00168         LCDparam.rows = 2;
00169         
00170     LCDparam.adresses[0] = 0;
00171     
00172     if (_type == LCD16x2B)
00173         LCDparam.adresses[1] = 40;
00174     else
00175         LCDparam.adresses[1] = 0x40;
00176         
00177     if (_type == LCD20x4) {
00178         LCDparam.adresses[2] = 0x14;
00179         LCDparam.adresses[3] = 0x54;}
00180     else {
00181         LCDparam.adresses[2] = 0;
00182         LCDparam.adresses[3] = 0;}
00183         
00184     LCDparam.delay = 50;            // 50 us delays as default              
00185 }
00186