Tianyang Chen / TextLCD

HW

Fork of TextLCD by Simon Ford

TextLCD.cpp@6:e4cb7ddee0d3, 2010-11-23 (annotated)

Committer:
simon
Date:
Tue Nov 23 14:26:19 2010 +0000
Revision:
6:e4cb7ddee0d3
Parent:
4:bf5b706f8d32
Child:
7:44f34c09bd37
Published as a library

Who changed what in which revision?

UserRevisionLine numberNew contents of line
simon 1:ac48b187213c 1 /* mbed TextLCD Library, for a 4-bit LCD based on HD44780
simon 6:e4cb7ddee0d3 2 * Copyright (c) 2007-2010, sford, http://mbed.org
simon 1:ac48b187213c 3 *
simon 1:ac48b187213c 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
simon 1:ac48b187213c 5 * of this software and associated documentation files (the "Software"), to deal
simon 1:ac48b187213c 6 * in the Software without restriction, including without limitation the rights
simon 1:ac48b187213c 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
simon 1:ac48b187213c 8 * copies of the Software, and to permit persons to whom the Software is
simon 1:ac48b187213c 9 * furnished to do so, subject to the following conditions:
simon 1:ac48b187213c 10 *
simon 1:ac48b187213c 11 * The above copyright notice and this permission notice shall be included in
simon 1:ac48b187213c 12 * all copies or substantial portions of the Software.
simon 1:ac48b187213c 13 *
simon 1:ac48b187213c 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
simon 1:ac48b187213c 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
simon 1:ac48b187213c 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
simon 1:ac48b187213c 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
simon 1:ac48b187213c 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
simon 1:ac48b187213c 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
simon 1:ac48b187213c 20 * THE SOFTWARE.
simon 1:ac48b187213c 21 */
simon 1:ac48b187213c 22
simon 1:ac48b187213c 23 #include "TextLCD.h"
simon 1:ac48b187213c 24 #include "mbed.h"
simon 1:ac48b187213c 25
simon 1:ac48b187213c 26 TextLCD::TextLCD(PinName rs, PinName e, PinName d0, PinName d1,
simon 1:ac48b187213c 27 PinName d2, PinName d3, LCDType type) : _rs(rs),
simon 1:ac48b187213c 28 _e(e), _d(d0, d1, d2, d3),
simon 1:ac48b187213c 29 _type(type) {
simon 1:ac48b187213c 30
simon 1:ac48b187213c 31 _e = 1;
simon 1:ac48b187213c 32 _rs = 0; // command mode
simon 1:ac48b187213c 33
simon 1:ac48b187213c 34 wait(0.015); // Wait 15ms to ensure powered up
simon 1:ac48b187213c 35
simon 1:ac48b187213c 36 // send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
simon 1:ac48b187213c 37 for (int i=0; i<3; i++) {
simon 1:ac48b187213c 38 writeByte(0x3);
simon 1:ac48b187213c 39 wait(0.00164); // this command takes 1.64ms, so wait for it
simon 1:ac48b187213c 40 }
simon 1:ac48b187213c 41 writeByte(0x2); // 4-bit mode
simon 1:ac48b187213c 42 wait(0.000040f); // most instructions take 40us
simon 1:ac48b187213c 43
simon 1:ac48b187213c 44 writeCommand(0x28); // Function set 001 BW N F - -
simon 1:ac48b187213c 45 writeCommand(0x0C);
simon 1:ac48b187213c 46 writeCommand(0x6); // Cursor Direction and Display Shift : 0000 01 CD S (CD 0-left, 1-right S(hift) 0-no, 1-yes
simon 1:ac48b187213c 47 cls();
simon 1:ac48b187213c 48 }
simon 1:ac48b187213c 49
simon 1:ac48b187213c 50 void TextLCD::character(int column, int row, int c) {
simon 1:ac48b187213c 51 int a = address(column, row);
simon 1:ac48b187213c 52 writeCommand(a);
simon 1:ac48b187213c 53 writeData(c);
simon 1:ac48b187213c 54 }
simon 1:ac48b187213c 55
simon 1:ac48b187213c 56 void TextLCD::cls() {
simon 1:ac48b187213c 57 writeCommand(0x01); // cls, and set cursor to 0
simon 1:ac48b187213c 58 wait(0.00164f); // This command takes 1.64 ms
simon 1:ac48b187213c 59 locate(0, 0);
simon 1:ac48b187213c 60 }
simon 1:ac48b187213c 61
simon 1:ac48b187213c 62 void TextLCD::locate(int column, int row) {
simon 1:ac48b187213c 63 _column = column;
simon 1:ac48b187213c 64 _row = row;
simon 1:ac48b187213c 65 }
simon 1:ac48b187213c 66
simon 1:ac48b187213c 67 int TextLCD::_putc(int value) {
simon 1:ac48b187213c 68 if (value == '\n') {
simon 1:ac48b187213c 69 _column = 0;
simon 1:ac48b187213c 70 _row++;
simon 1:ac48b187213c 71 if (_row >= rows()) {
simon 1:ac48b187213c 72 _row = 0;
simon 1:ac48b187213c 73 }
simon 1:ac48b187213c 74 } else {
simon 1:ac48b187213c 75 character(_column, _row, value);
simon 1:ac48b187213c 76 _column++;
simon 1:ac48b187213c 77 if (_column >= columns()) {
simon 1:ac48b187213c 78 _column = 0;
simon 1:ac48b187213c 79 _row++;
simon 1:ac48b187213c 80 if (_row >= rows()) {
simon 1:ac48b187213c 81 _row = 0;
simon 1:ac48b187213c 82 }
simon 1:ac48b187213c 83 }
simon 1:ac48b187213c 84 }
simon 1:ac48b187213c 85 return value;
simon 1:ac48b187213c 86 }
simon 1:ac48b187213c 87
simon 1:ac48b187213c 88 int TextLCD::_getc() {
simon 1:ac48b187213c 89 return -1;
simon 1:ac48b187213c 90 }
simon 1:ac48b187213c 91
simon 1:ac48b187213c 92 void TextLCD::writeByte(int value) {
simon 1:ac48b187213c 93 _d = value >> 4;
simon 1:ac48b187213c 94 wait(0.000040f); // most instructions take 40us
simon 1:ac48b187213c 95 _e = 0;
simon 1:ac48b187213c 96 wait(0.000040f);
simon 1:ac48b187213c 97 _e = 1;
simon 1:ac48b187213c 98 _d = value >> 0;
simon 1:ac48b187213c 99 wait(0.000040f);
simon 1:ac48b187213c 100 _e = 0;
simon 1:ac48b187213c 101 wait(0.000040f); // most instructions take 40us
simon 1:ac48b187213c 102 _e = 1;
simon 1:ac48b187213c 103 }
simon 1:ac48b187213c 104
simon 1:ac48b187213c 105 void TextLCD::writeCommand(int command) {
simon 1:ac48b187213c 106 _rs = 0;
simon 1:ac48b187213c 107 writeByte(command);
simon 1:ac48b187213c 108 }
simon 1:ac48b187213c 109
simon 1:ac48b187213c 110 void TextLCD::writeData(int data) {
simon 1:ac48b187213c 111 _rs = 1;
simon 1:ac48b187213c 112 writeByte(data);
simon 1:ac48b187213c 113 }
simon 1:ac48b187213c 114
simon 1:ac48b187213c 115 int TextLCD::address(int column, int row) {
simon 1:ac48b187213c 116 switch (_type) {
simon 1:ac48b187213c 117 case LCD20x4:
simon 1:ac48b187213c 118 switch (row) {
simon 1:ac48b187213c 119 case 0:
simon 1:ac48b187213c 120 return 0x80 + column;
simon 1:ac48b187213c 121 case 1:
simon 1:ac48b187213c 122 return 0xc0 + column;
simon 1:ac48b187213c 123 case 2:
simon 1:ac48b187213c 124 return 0x94 + column;
simon 1:ac48b187213c 125 case 3:
simon 1:ac48b187213c 126 return 0xd4 + column;
simon 1:ac48b187213c 127 }
simon 1:ac48b187213c 128 case LCD16x2B:
simon 4:bf5b706f8d32 129 return 0x80 + (row * 40) + column;
simon 1:ac48b187213c 130 case LCD16x2:
simon 1:ac48b187213c 131 case LCD20x2:
simon 1:ac48b187213c 132 default:
simon 4:bf5b706f8d32 133 return 0x80 + (row * 0x40) + column;
simon 1:ac48b187213c 134 }
simon 1:ac48b187213c 135 }
simon 1:ac48b187213c 136
simon 1:ac48b187213c 137 int TextLCD::columns() {
simon 1:ac48b187213c 138 switch (_type) {
simon 1:ac48b187213c 139 case LCD20x4:
simon 1:ac48b187213c 140 case LCD20x2:
simon 1:ac48b187213c 141 return 20;
simon 1:ac48b187213c 142 case LCD16x2:
simon 1:ac48b187213c 143 case LCD16x2B:
simon 1:ac48b187213c 144 default:
simon 1:ac48b187213c 145 return 16;
simon 1:ac48b187213c 146 }
simon 1:ac48b187213c 147 }
simon 1:ac48b187213c 148
simon 1:ac48b187213c 149 int TextLCD::rows() {
simon 1:ac48b187213c 150 switch (_type) {
simon 1:ac48b187213c 151 case LCD20x4:
simon 1:ac48b187213c 152 return 4;
simon 1:ac48b187213c 153 case LCD16x2:
simon 1:ac48b187213c 154 case LCD16x2B:
simon 1:ac48b187213c 155 case LCD20x2:
simon 1:ac48b187213c 156 default:
simon 1:ac48b187213c 157 return 2;
simon 1:ac48b187213c 158 }
simon 1:ac48b187213c 159 }