cristian rodriguez / Mbed 2 deprecated lcd

lcd

Dependencies:   Keypad mbed

TextLCD_20X4.cpp@0:33c425e06a2c, 2018-10-03 (annotated)

Committer:
crizz777
Date:
Wed Oct 03 00:42:11 2018 +0000
Revision:
0:33c425e06a2c
lcd

Who changed what in which revision?

UserRevisionLine numberNew contents of line
crizz777 0:33c425e06a2c 1 /* mbed TextLCD Library
crizz777 0:33c425e06a2c 2 * Copyright (c) 2007-2009 sford
crizz777 0:33c425e06a2c 3 * Released under the MIT License: http://mbed.org/license/mit
crizz777 0:33c425e06a2c 4 *
crizz777 0:33c425e06a2c 5 * TODO: Needs serious rework/neatening up!
crizz777 0:33c425e06a2c 6 */
crizz777 0:33c425e06a2c 7
crizz777 0:33c425e06a2c 8 /*
crizz777 0:33c425e06a2c 9 * 2010/05/14 modified for 20X4 LCD by ym1784
crizz777 0:33c425e06a2c 10 */
crizz777 0:33c425e06a2c 11
crizz777 0:33c425e06a2c 12 #include "TextLCD_20X4.h"
crizz777 0:33c425e06a2c 13
crizz777 0:33c425e06a2c 14 #include "mbed.h"
crizz777 0:33c425e06a2c 15 #include "error.h"
crizz777 0:33c425e06a2c 16
crizz777 0:33c425e06a2c 17 using namespace mbed;
crizz777 0:33c425e06a2c 18
crizz777 0:33c425e06a2c 19 /*
crizz777 0:33c425e06a2c 20 * useful info found at http://www.a-netz.de/lcd.en.php
crizz777 0:33c425e06a2c 21 *
crizz777 0:33c425e06a2c 22 *
crizz777 0:33c425e06a2c 23 * Initialization
crizz777 0:33c425e06a2c 24 * ==============
crizz777 0:33c425e06a2c 25 *
crizz777 0:33c425e06a2c 26 * After attaching the supply voltage/after a reset, the display needs to be brought in to a defined state
crizz777 0:33c425e06a2c 27 *
crizz777 0:33c425e06a2c 28 * - wait approximately 15 ms so the display is ready to execute commands
crizz777 0:33c425e06a2c 29 * - Execute the command 0x30 ("Display Settings") three times (wait 1,64ms after each command, the busy flag cannot be queried now).
crizz777 0:33c425e06a2c 30 * - The display is in 8 bit mode, so if you have only connected 4 data pins you should only transmit the higher nibble of each command.
crizz777 0:33c425e06a2c 31 * - If you want to use the 4 bit mode, now you can execute the command to switch over to this mode now.
crizz777 0:33c425e06a2c 32 * - Execute the "clear display" command
crizz777 0:33c425e06a2c 33 *
crizz777 0:33c425e06a2c 34 * Timing
crizz777 0:33c425e06a2c 35 * ======
crizz777 0:33c425e06a2c 36 *
crizz777 0:33c425e06a2c 37 * Nearly all commands transmitted to the display need 40us for execution.
crizz777 0:33c425e06a2c 38 * Exceptions are the commands "Clear Display and Reset" and "Set Cursor to Start Position"
crizz777 0:33c425e06a2c 39 * These commands need 1.64ms for execution. These timings are valid for all displays working with an
crizz777 0:33c425e06a2c 40 * internal clock of 250kHz. But I do not know any displays that use other frequencies. Any time you
crizz777 0:33c425e06a2c 41 * can use the busy flag to test if the display is ready to accept the next command.
crizz777 0:33c425e06a2c 42 *
crizz777 0:33c425e06a2c 43 * _e is kept high apart from calling clock
crizz777 0:33c425e06a2c 44 * _rw is kept 0 (write) apart from actions that uyse it differently
crizz777 0:33c425e06a2c 45 * -> on this program, the _rw is not used ... ym1784
crizz777 0:33c425e06a2c 46 * _rs is set by the data/command writes
crizz777 0:33c425e06a2c 47 */
crizz777 0:33c425e06a2c 48
crizz777 0:33c425e06a2c 49 TextLCD_20X4::TextLCD_20X4(PinName rs, PinName e, PinName d0, PinName d1,
crizz777 0:33c425e06a2c 50 PinName d2, PinName d3, int columns, int rows) : _rs(rs), _e(e), _d(d0, d1, d2, d3),
crizz777 0:33c425e06a2c 51 _columns(columns), _rows(rows) {
crizz777 0:33c425e06a2c 52
crizz777 0:33c425e06a2c 53 _rows = 4;
crizz777 0:33c425e06a2c 54 _columns = 20;
crizz777 0:33c425e06a2c 55 // Mon, 27 Apr 2009 23:32:34 +0200
crizz777 0:33c425e06a2c 56 // Kevin Konradt:
crizz777 0:33c425e06a2c 57 // When using a LCD with 1 row x 16 characters
crizz777 0:33c425e06a2c 58 // instead of 2x16, try changing _columns to 8.
crizz777 0:33c425e06a2c 59 // (display seems to split the 16 characters into
crizz777 0:33c425e06a2c 60 // 2 virtual rows with 8 characters each.)
crizz777 0:33c425e06a2c 61 //
crizz777 0:33c425e06a2c 62 // 2010/05/14 ym1784
crizz777 0:33c425e06a2c 63 // This program is only for 4 rows x 20 characters specific
crizz777 0:33c425e06a2c 64
crizz777 0:33c425e06a2c 65 // _rw = 0; // on this program, the _rw is not used ... ym1784
crizz777 0:33c425e06a2c 66 _e = 1;
crizz777 0:33c425e06a2c 67 _rs = 0; // command mode
crizz777 0:33c425e06a2c 68
crizz777 0:33c425e06a2c 69 // Should theoretically wait 15ms, but most things will be powered up pre-reset
crizz777 0:33c425e06a2c 70 // so i'll disable that for the minute. If implemented, could wait 15ms post reset
crizz777 0:33c425e06a2c 71 // instead
crizz777 0:33c425e06a2c 72 wait(0.015); // for safety ... ym1784
crizz777 0:33c425e06a2c 73
crizz777 0:33c425e06a2c 74 // send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
crizz777 0:33c425e06a2c 75 for(int i=0; i<3; i++) {
crizz777 0:33c425e06a2c 76 writeNibble(0x3);
crizz777 0:33c425e06a2c 77 wait(0.00164); // this command takes 1.64ms, so wait for it
crizz777 0:33c425e06a2c 78 }
crizz777 0:33c425e06a2c 79 writeNibble(0x2); // 4-bit mode
crizz777 0:33c425e06a2c 80
crizz777 0:33c425e06a2c 81 writeCommand(0x28); // Function set 001 BW N F - -
crizz777 0:33c425e06a2c 82 writeCommand(0x0C);
crizz777 0:33c425e06a2c 83 writeCommand(0x6); // Cursor Direction and Display Shift : 0000 01 CD S (CD 0-left, 1-right S(hift) 0-no, 1-yes
crizz777 0:33c425e06a2c 84
crizz777 0:33c425e06a2c 85 cls();
crizz777 0:33c425e06a2c 86 }
crizz777 0:33c425e06a2c 87
crizz777 0:33c425e06a2c 88 int TextLCD_20X4::_putc(int value) {
crizz777 0:33c425e06a2c 89 if(value == '\n') {
crizz777 0:33c425e06a2c 90 newline();
crizz777 0:33c425e06a2c 91 } else {
crizz777 0:33c425e06a2c 92 writeData(value);
crizz777 0:33c425e06a2c 93 }
crizz777 0:33c425e06a2c 94 return value;
crizz777 0:33c425e06a2c 95 }
crizz777 0:33c425e06a2c 96
crizz777 0:33c425e06a2c 97 int TextLCD_20X4::_getc() {
crizz777 0:33c425e06a2c 98 return 0;
crizz777 0:33c425e06a2c 99 }
crizz777 0:33c425e06a2c 100
crizz777 0:33c425e06a2c 101 void TextLCD_20X4::newline() {
crizz777 0:33c425e06a2c 102 _column = 0;
crizz777 0:33c425e06a2c 103 _row++;
crizz777 0:33c425e06a2c 104 if(_row >= _rows) {
crizz777 0:33c425e06a2c 105 _row = 0;
crizz777 0:33c425e06a2c 106 }
crizz777 0:33c425e06a2c 107 locate(_column, _row);
crizz777 0:33c425e06a2c 108 }
crizz777 0:33c425e06a2c 109
crizz777 0:33c425e06a2c 110 void TextLCD_20X4::locate(int column, int row) {
crizz777 0:33c425e06a2c 111 if(column < 0 || column >= _columns || row < 0 || row >= _rows) {
crizz777 0:33c425e06a2c 112 error("locate(%d,%d) out of range on %dx%d display", column, row, _columns, _rows);
crizz777 0:33c425e06a2c 113 return;
crizz777 0:33c425e06a2c 114 }
crizz777 0:33c425e06a2c 115 _row = row;
crizz777 0:33c425e06a2c 116 _column = column;
crizz777 0:33c425e06a2c 117 // modified for 20X4 LCD
crizz777 0:33c425e06a2c 118 switch (_row) {
crizz777 0:33c425e06a2c 119 case (0) : address = 0x80 + _column;
crizz777 0:33c425e06a2c 120 break;
crizz777 0:33c425e06a2c 121 case (1) : address = 0xc0 + _column;
crizz777 0:33c425e06a2c 122 break;
crizz777 0:33c425e06a2c 123 case (2) : address = 0x94 + _column;
crizz777 0:33c425e06a2c 124 break;
crizz777 0:33c425e06a2c 125 case (3) : address = 0xd4 + _column;
crizz777 0:33c425e06a2c 126 break;
crizz777 0:33c425e06a2c 127 } // switch
crizz777 0:33c425e06a2c 128 writeCommand(address);
crizz777 0:33c425e06a2c 129 }
crizz777 0:33c425e06a2c 130
crizz777 0:33c425e06a2c 131 void TextLCD_20X4::cls() {
crizz777 0:33c425e06a2c 132 writeCommand(0x01); // Clear Display
crizz777 0:33c425e06a2c 133 wait(0.00164f); // This command takes 1.64 ms
crizz777 0:33c425e06a2c 134 // locate(0, 0); // We don't have to do this here
crizz777 0:33c425e06a2c 135 }
crizz777 0:33c425e06a2c 136
crizz777 0:33c425e06a2c 137 void TextLCD_20X4::reset() {
crizz777 0:33c425e06a2c 138 cls();
crizz777 0:33c425e06a2c 139 }
crizz777 0:33c425e06a2c 140
crizz777 0:33c425e06a2c 141 void TextLCD_20X4::clock() {
crizz777 0:33c425e06a2c 142 wait(0.000040f);
crizz777 0:33c425e06a2c 143 _e = 0;
crizz777 0:33c425e06a2c 144 wait(0.000040f); // most instructions take 40us
crizz777 0:33c425e06a2c 145 _e = 1;
crizz777 0:33c425e06a2c 146 }
crizz777 0:33c425e06a2c 147
crizz777 0:33c425e06a2c 148 void TextLCD_20X4::writeNibble(int value) {
crizz777 0:33c425e06a2c 149 _d = value;
crizz777 0:33c425e06a2c 150 clock();
crizz777 0:33c425e06a2c 151 }
crizz777 0:33c425e06a2c 152
crizz777 0:33c425e06a2c 153 void TextLCD_20X4::writeByte(int value) {
crizz777 0:33c425e06a2c 154 writeNibble(value >> 4);
crizz777 0:33c425e06a2c 155 writeNibble(value >> 0);
crizz777 0:33c425e06a2c 156 }
crizz777 0:33c425e06a2c 157
crizz777 0:33c425e06a2c 158 void TextLCD_20X4::writeCommand(int command) {
crizz777 0:33c425e06a2c 159 _rs = 0;
crizz777 0:33c425e06a2c 160 writeByte(command);
crizz777 0:33c425e06a2c 161 }
crizz777 0:33c425e06a2c 162
crizz777 0:33c425e06a2c 163 void TextLCD_20X4::writeData(int data) {
crizz777 0:33c425e06a2c 164 _rs = 1;
crizz777 0:33c425e06a2c 165 writeByte(data);
crizz777 0:33c425e06a2c 166 _column++;
crizz777 0:33c425e06a2c 167 if(_column >= _columns) {
crizz777 0:33c425e06a2c 168 newline();
crizz777 0:33c425e06a2c 169 }
crizz777 0:33c425e06a2c 170 }