Pranav Sawant / TextLCD

Oct122012mbedLab

Dependents:   Lab3_VoiceMeter

Fork of TextLCD by Simon Ford

TextLCD.cpp@8:bd49ebdd4f64, 2012-10-12 (annotated)

Committer:
psawant9
Date:
Fri Oct 12 16:02:26 2012 +0000
Revision:
8:bd49ebdd4f64
Parent:
4:bf5b706f8d32 
Done

Who changed what in which revision?

UserRevisionLine numberNew contents of line
psawant9 8:bd49ebdd4f64 1 /* mbed TextLCD Library, for a 4-bit LCD based on HD44780
psawant9 8:bd49ebdd4f64 2 * Copyright (c) 2007-2010, sford
psawant9 8:bd49ebdd4f64 3 *
psawant9 8:bd49ebdd4f64 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
psawant9 8:bd49ebdd4f64 5 * of this software and associated documentation files (the "Software"), to deal
psawant9 8:bd49ebdd4f64 6 * in the Software without restriction, including without limitation the rights
psawant9 8:bd49ebdd4f64 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
psawant9 8:bd49ebdd4f64 8 * copies of the Software, and to permit persons to whom the Software is
psawant9 8:bd49ebdd4f64 9 * furnished to do so, subject to the following conditions:
psawant9 8:bd49ebdd4f64 10 *
psawant9 8:bd49ebdd4f64 11 * The above copyright notice and this permission notice shall be included in
psawant9 8:bd49ebdd4f64 12 * all copies or substantial portions of the Software.
psawant9 8:bd49ebdd4f64 13 *
psawant9 8:bd49ebdd4f64 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
psawant9 8:bd49ebdd4f64 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
psawant9 8:bd49ebdd4f64 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
psawant9 8:bd49ebdd4f64 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
psawant9 8:bd49ebdd4f64 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
psawant9 8:bd49ebdd4f64 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
psawant9 8:bd49ebdd4f64 20 * THE SOFTWARE.
psawant9 8:bd49ebdd4f64 21 */
psawant9 8:bd49ebdd4f64 22
psawant9 8:bd49ebdd4f64 23 #include "TextLCD.h"
psawant9 8:bd49ebdd4f64 24 #include "mbed.h"
psawant9 8:bd49ebdd4f64 25
psawant9 8:bd49ebdd4f64 26 TextLCD::TextLCD(PinName rs, PinName e, PinName d0, PinName d1,
psawant9 8:bd49ebdd4f64 27 PinName d2, PinName d3, LCDType type) : _rs(rs),
psawant9 8:bd49ebdd4f64 28 _e(e), _d(d0, d1, d2, d3),
psawant9 8:bd49ebdd4f64 29 _type(type) {
psawant9 8:bd49ebdd4f64 30
psawant9 8:bd49ebdd4f64 31 _e = 1;
psawant9 8:bd49ebdd4f64 32 _rs = 0; // command mode
psawant9 8:bd49ebdd4f64 33
psawant9 8:bd49ebdd4f64 34 wait(0.015); // Wait 15ms to ensure powered up
psawant9 8:bd49ebdd4f64 35
psawant9 8:bd49ebdd4f64 36 // send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
psawant9 8:bd49ebdd4f64 37 for (int i=0; i<3; i++) {
psawant9 8:bd49ebdd4f64 38 writeByte(0x3);
psawant9 8:bd49ebdd4f64 39 wait(0.00164); // this command takes 1.64ms, so wait for it
psawant9 8:bd49ebdd4f64 40 }
psawant9 8:bd49ebdd4f64 41 writeByte(0x2); // 4-bit mode
psawant9 8:bd49ebdd4f64 42 wait(0.000040f); // most instructions take 40us
psawant9 8:bd49ebdd4f64 43
psawant9 8:bd49ebdd4f64 44 writeCommand(0x28); // Function set 001 BW N F - -
psawant9 8:bd49ebdd4f64 45 writeCommand(0x0C);
psawant9 8:bd49ebdd4f64 46 writeCommand(0x6); // Cursor Direction and Display Shift : 0000 01 CD S (CD 0-left, 1-right S(hift) 0-no, 1-yes
psawant9 8:bd49ebdd4f64 47 cls();
psawant9 8:bd49ebdd4f64 48 }
psawant9 8:bd49ebdd4f64 49
psawant9 8:bd49ebdd4f64 50 void TextLCD::character(int column, int row, int c) {
psawant9 8:bd49ebdd4f64 51 int a = address(column, row);
psawant9 8:bd49ebdd4f64 52 writeCommand(a);
psawant9 8:bd49ebdd4f64 53 writeData(c);
psawant9 8:bd49ebdd4f64 54 }
psawant9 8:bd49ebdd4f64 55
psawant9 8:bd49ebdd4f64 56 void TextLCD::cls() {
psawant9 8:bd49ebdd4f64 57 writeCommand(0x01); // cls, and set cursor to 0
psawant9 8:bd49ebdd4f64 58 wait(0.00164f); // This command takes 1.64 ms
psawant9 8:bd49ebdd4f64 59 locate(0, 0);
psawant9 8:bd49ebdd4f64 60 }
psawant9 8:bd49ebdd4f64 61
psawant9 8:bd49ebdd4f64 62 void TextLCD::locate(int column, int row) {
psawant9 8:bd49ebdd4f64 63 _column = column;
psawant9 8:bd49ebdd4f64 64 _row = row;
psawant9 8:bd49ebdd4f64 65 }
psawant9 8:bd49ebdd4f64 66
psawant9 8:bd49ebdd4f64 67 int TextLCD::_putc(int value) {
psawant9 8:bd49ebdd4f64 68 if (value == '\n') {
psawant9 8:bd49ebdd4f64 69 _column = 0;
psawant9 8:bd49ebdd4f64 70 _row++;
psawant9 8:bd49ebdd4f64 71 if (_row >= rows()) {
psawant9 8:bd49ebdd4f64 72 _row = 0;
psawant9 8:bd49ebdd4f64 73 }
psawant9 8:bd49ebdd4f64 74 } else {
psawant9 8:bd49ebdd4f64 75 character(_column, _row, value);
psawant9 8:bd49ebdd4f64 76 _column++;
psawant9 8:bd49ebdd4f64 77 if (_column >= columns()) {
psawant9 8:bd49ebdd4f64 78 _column = 0;
psawant9 8:bd49ebdd4f64 79 _row++;
psawant9 8:bd49ebdd4f64 80 if (_row >= rows()) {
psawant9 8:bd49ebdd4f64 81 _row = 0;
psawant9 8:bd49ebdd4f64 82 }
psawant9 8:bd49ebdd4f64 83 }
psawant9 8:bd49ebdd4f64 84 }
psawant9 8:bd49ebdd4f64 85 return value;
psawant9 8:bd49ebdd4f64 86 }
psawant9 8:bd49ebdd4f64 87
psawant9 8:bd49ebdd4f64 88 int TextLCD::_getc() {
psawant9 8:bd49ebdd4f64 89 return -1;
psawant9 8:bd49ebdd4f64 90 }
psawant9 8:bd49ebdd4f64 91
psawant9 8:bd49ebdd4f64 92 void TextLCD::writeByte(int value) {
psawant9 8:bd49ebdd4f64 93 _d = value >> 4;
psawant9 8:bd49ebdd4f64 94 wait(0.000040f); // most instructions take 40us
psawant9 8:bd49ebdd4f64 95 _e = 0;
psawant9 8:bd49ebdd4f64 96 wait(0.000040f);
psawant9 8:bd49ebdd4f64 97 _e = 1;
psawant9 8:bd49ebdd4f64 98 _d = value >> 0;
psawant9 8:bd49ebdd4f64 99 wait(0.000040f);
psawant9 8:bd49ebdd4f64 100 _e = 0;
psawant9 8:bd49ebdd4f64 101 wait(0.000040f); // most instructions take 40us
psawant9 8:bd49ebdd4f64 102 _e = 1;
psawant9 8:bd49ebdd4f64 103 }
psawant9 8:bd49ebdd4f64 104
psawant9 8:bd49ebdd4f64 105 void TextLCD::writeCommand(int command) {
psawant9 8:bd49ebdd4f64 106 _rs = 0;
psawant9 8:bd49ebdd4f64 107 writeByte(command);
psawant9 8:bd49ebdd4f64 108 }
psawant9 8:bd49ebdd4f64 109
psawant9 8:bd49ebdd4f64 110 void TextLCD::writeData(int data) {
psawant9 8:bd49ebdd4f64 111 _rs = 1;
psawant9 8:bd49ebdd4f64 112 writeByte(data);
psawant9 8:bd49ebdd4f64 113 }
psawant9 8:bd49ebdd4f64 114
psawant9 8:bd49ebdd4f64 115 int TextLCD::address(int column, int row) {
psawant9 8:bd49ebdd4f64 116 switch (_type) {
psawant9 8:bd49ebdd4f64 117 case LCD20x4:
psawant9 8:bd49ebdd4f64 118 switch (row) {
psawant9 8:bd49ebdd4f64 119 case 0:
psawant9 8:bd49ebdd4f64 120 return 0x80 + column;
psawant9 8:bd49ebdd4f64 121 case 1:
psawant9 8:bd49ebdd4f64 122 return 0xc0 + column;
psawant9 8:bd49ebdd4f64 123 case 2:
psawant9 8:bd49ebdd4f64 124 return 0x94 + column;
psawant9 8:bd49ebdd4f64 125 case 3:
psawant9 8:bd49ebdd4f64 126 return 0xd4 + column;
psawant9 8:bd49ebdd4f64 127 }
psawant9 8:bd49ebdd4f64 128 case LCD16x2B:
psawant9 8:bd49ebdd4f64 129 return 0x80 + (row * 40) + column;
psawant9 8:bd49ebdd4f64 130 case LCD16x2:
psawant9 8:bd49ebdd4f64 131 case LCD20x2:
psawant9 8:bd49ebdd4f64 132 default:
psawant9 8:bd49ebdd4f64 133 return 0x80 + (row * 0x40) + column;
psawant9 8:bd49ebdd4f64 134 }
psawant9 8:bd49ebdd4f64 135 }
psawant9 8:bd49ebdd4f64 136
psawant9 8:bd49ebdd4f64 137 int TextLCD::columns() {
psawant9 8:bd49ebdd4f64 138 switch (_type) {
psawant9 8:bd49ebdd4f64 139 case LCD20x4:
psawant9 8:bd49ebdd4f64 140 case LCD20x2:
psawant9 8:bd49ebdd4f64 141 return 20;
psawant9 8:bd49ebdd4f64 142 case LCD16x2:
psawant9 8:bd49ebdd4f64 143 case LCD16x2B:
psawant9 8:bd49ebdd4f64 144 default:
psawant9 8:bd49ebdd4f64 145 return 16;
psawant9 8:bd49ebdd4f64 146 }
psawant9 8:bd49ebdd4f64 147 }
psawant9 8:bd49ebdd4f64 148
psawant9 8:bd49ebdd4f64 149 int TextLCD::rows() {
psawant9 8:bd49ebdd4f64 150 switch (_type) {
psawant9 8:bd49ebdd4f64 151 case LCD20x4:
psawant9 8:bd49ebdd4f64 152 return 4;
psawant9 8:bd49ebdd4f64 153 case LCD16x2:
psawant9 8:bd49ebdd4f64 154 case LCD16x2B:
psawant9 8:bd49ebdd4f64 155 case LCD20x2:
psawant9 8:bd49ebdd4f64 156 default:
psawant9 8:bd49ebdd4f64 157 return 2;
psawant9 8:bd49ebdd4f64 158 }
psawant9 8:bd49ebdd4f64 159 }