TextLCD.cpp

00001 /* mbed TextLCD Library, for a 4-bit LCD based on HD44780
00002  * Copyright (c) 2007-2010, sford
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00020  * THE SOFTWARE.
00021  */
00022 
00023 /*
00024  * Modified for star board orange by Shinichiro Nakamura. (CuBeatSystems)
00025  *
00026  * ID : shintamainjp
00027  * Added : RW-
00028  */
00029 
00030 #include "TextLCD.h"
00031 #include "mbed.h"
00032 
00033 TextLCD::TextLCD(PinName rs, PinName rw, PinName e, PinName d0, PinName d1,
00034                  PinName d2, PinName d3, LCDType type) : _rs(rs), _rw(rw),
00035         _e(e), _d(d0, d1, d2, d3),
00036         _type(type) {
00037 
00038     _e  = 1;
00039     _rs = 0;            // command mode
00040     _rw = 0;
00041 
00042     wait(0.015);        // Wait 15ms to ensure powered up
00043 
00044     // send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
00045     for (int i=0; i<3; i++) {
00046         writeByte(0x3);
00047         wait(0.00164);  // this command takes 1.64ms, so wait for it
00048     }
00049     writeByte(0x2);     // 4-bit mode
00050     wait(0.000040f);    // most instructions take 40us
00051 
00052     writeCommand(0x28); // Function set 001 BW N F - -
00053     writeCommand(0x0C);
00054     writeCommand(0x6);  // Cursor Direction and Display Shift : 0000 01 CD S (CD 0-left, 1-right S(hift) 0-no, 1-yes
00055     cls();
00056 }
00057 
00058 void TextLCD::character(int column, int row, int c) {
00059     int a = address(column, row);
00060     writeCommand(a);
00061     writeData(c);
00062 }
00063 
00064 void TextLCD::cls() {
00065     writeCommand(0x01); // cls, and set cursor to 0
00066     wait(0.00164f);     // This command takes 1.64 ms
00067     locate(0, 0);
00068 }
00069 
00070 void TextLCD::locate(int column, int row) {
00071     _column = column;
00072     _row = row;
00073 }
00074 
00075 int TextLCD::_putc(int value) {
00076     if (value == '\n') {
00077         _column = 0;
00078         _row++;
00079         if (_row >= rows()) {
00080             _row = 0;
00081         }
00082     } else {
00083         character(_column, _row, value);
00084         _column++;
00085         if (_column >= columns()) {
00086             _column = 0;
00087             _row++;
00088             if (_row >= rows()) {
00089                 _row = 0;
00090             }
00091         }
00092     }
00093     return value;
00094 }
00095 
00096 int TextLCD::_getc() {
00097     return -1;
00098 }
00099 
00100 void TextLCD::writeByte(int value) {
00101     _d = value >> 4;
00102     wait(0.000040f); // most instructions take 40us
00103     _e = 0;
00104     wait(0.000040f);
00105     _e = 1;
00106     _d = value >> 0;
00107     wait(0.000040f);
00108     _e = 0;
00109     wait(0.000040f);  // most instructions take 40us
00110     _e = 1;
00111 }
00112 
00113 void TextLCD::writeCommand(int command) {
00114     _rs = 0;
00115     writeByte(command);
00116 }
00117 
00118 void TextLCD::writeData(int data) {
00119     _rs = 1;
00120     writeByte(data);
00121 }
00122 
00123 int TextLCD::address(int column, int row) {
00124     switch (_type) {
00125         case LCD20x4:
00126             switch (row) {
00127                 case 0:
00128                     return 0x80 + column;
00129                 case 1:
00130                     return 0xc0 + column;
00131                 case 2:
00132                     return 0x94 + column;
00133                 case 3:
00134                     return 0xd4 + column;
00135             }
00136         case LCD16x2B:
00137             return 0x80 + (row * 40) + column;
00138         case LCD16x2:
00139         case LCD20x2:
00140         default:
00141             return 0x80 + (row * 0x40) + column;
00142     }
00143 }
00144 
00145 int TextLCD::columns() {
00146     switch (_type) {
00147         case LCD20x4:
00148         case LCD20x2:
00149             return 20;
00150         case LCD16x2:
00151         case LCD16x2B:
00152         default:
00153             return 16;
00154     }
00155 }
00156 
00157 int TextLCD::rows() {
00158     switch (_type) {
00159         case LCD20x4:
00160             return 4;
00161         case LCD16x2:
00162         case LCD16x2B:
00163         case LCD20x2:
00164         default:
00165             return 2;
00166     }
00167 }