easytronic / i2clcd

faster data display from previous driver

TextLCD.cpp@0:3fad116e266c, 2016-02-22 (annotated)

Committer:
mijimy
Date:
Mon Feb 22 08:04:43 2016 +0000
Revision:
0:3fad116e266c
faster data rate updated

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mijimy 0:3fad116e266c 1 /* mbed I2CTextLCD Library, for a 4-bit LCD driven by I2C and a PCF8574
mijimy 0:3fad116e266c 2 * Copyright (c) 2007-2010, sford, rcocking
mijimy 0:3fad116e266c 3 *
mijimy 0:3fad116e266c 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
mijimy 0:3fad116e266c 5 * of this software and associated documentation files (the "Software"), to deal
mijimy 0:3fad116e266c 6 * in the Software without restriction, including without limitation the rights
mijimy 0:3fad116e266c 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
mijimy 0:3fad116e266c 8 * copies of the Software, and to permit persons to whom the Software is
mijimy 0:3fad116e266c 9 * furnished to do so, subject to the following conditions:
mijimy 0:3fad116e266c 10 *
mijimy 0:3fad116e266c 11 * The above copyright notice and this permission notice shall be included in
mijimy 0:3fad116e266c 12 * all copies or substantial portions of the Software.
mijimy 0:3fad116e266c 13 *
mijimy 0:3fad116e266c 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
mijimy 0:3fad116e266c 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
mijimy 0:3fad116e266c 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
mijimy 0:3fad116e266c 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
mijimy 0:3fad116e266c 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
mijimy 0:3fad116e266c 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
mijimy 0:3fad116e266c 20 * THE SOFTWARE.
mijimy 0:3fad116e266c 21 */
mijimy 0:3fad116e266c 22
mijimy 0:3fad116e266c 23 /* This is a hack of Simon Ford's direct-driven TextLCD code.
mijimy 0:3fad116e266c 24 * It should be refactored to extract a common superclass
mijimy 0:3fad116e266c 25 * but my C++ isn't yet good enough :)
mijimy 0:3fad116e266c 26 *
mijimy 0:3fad116e266c 27 * The code assumes the following connections between the PCF8574
mijimy 0:3fad116e266c 28 * and the LCD
mijimy 0:3fad116e266c 29 *
mijimy 0:3fad116e266c 30 * nc - D0
mijimy 0:3fad116e266c 31 * nc - D1
mijimy 0:3fad116e266c 32 * nc - D2
mijimy 0:3fad116e266c 33 * nc - D3
mijimy 0:3fad116e266c 34 * P0 - D4
mijimy 0:3fad116e266c 35 * P1 - D5
mijimy 0:3fad116e266c 36 * P2 - D6
mijimy 0:3fad116e266c 37 * P3 - D7
mijimy 0:3fad116e266c 38 * P4 - E
mijimy 0:3fad116e266c 39 * P5 - nc
mijimy 0:3fad116e266c 40 * P6 - nc
mijimy 0:3fad116e266c 41 * P7 - RS
mijimy 0:3fad116e266c 42 * gnd - R/W
mijimy 0:3fad116e266c 43 *
mijimy 0:3fad116e266c 44 * D0-3 of the LCD are not connected because we work in 4-bit mode
mijimy 0:3fad116e266c 45 * R/W is hardwired to gound, as we only ever write to the LCD
mijimy 0:3fad116e266c 46 * A0-2 on the PCF8574 can be set in any combination; you will need to modify
mijimy 0:3fad116e266c 47 * the I2C address in the I2CTextLCD constructor.
mijimy 0:3fad116e266c 48 * Remember that the mbed uses 8-bit addresses, which should be
mijimy 0:3fad116e266c 49 * in the range 0x40-0x4E for the PCF8574
mijimy 0:3fad116e266c 50 */
mijimy 0:3fad116e266c 51 #include "TextLCD.h"
mijimy 0:3fad116e266c 52 #include "mbed.h"
mijimy 0:3fad116e266c 53
mijimy 0:3fad116e266c 54
mijimy 0:3fad116e266c 55 TextLCD::TextLCD(PinName sda, PinName scl, int i2cAddress, LCDType type) : _i2c(sda, scl), _i2cAddress(i2cAddress) , _type(type){
mijimy 0:3fad116e266c 56 // _i2cAddress = i2cAddress;
mijimy 0:3fad116e266c 57 writeByte(E_ON,false);
mijimy 0:3fad116e266c 58 wait(0.015); // Wait 15ms to ensure powered up
mijimy 0:3fad116e266c 59
mijimy 0:3fad116e266c 60 // send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
mijimy 0:3fad116e266c 61 for (int i=0; i<3; i++) {
mijimy 0:3fad116e266c 62 writeByte(0x3, false);
mijimy 0:3fad116e266c 63 wait(0.00164); // this command takes 1.64ms, so wait for it
mijimy 0:3fad116e266c 64 }
mijimy 0:3fad116e266c 65 writeByte(0x2, false); // 4-bit mode
mijimy 0:3fad116e266c 66 wait(0.000040f); // most instructions take 40us
mijimy 0:3fad116e266c 67
mijimy 0:3fad116e266c 68 writeCommand(0x28); // Function set 001 BW N F - -
mijimy 0:3fad116e266c 69 writeCommand(0x0C);
mijimy 0:3fad116e266c 70 writeCommand(0x6); // Cursor Direction and Display Shift : 0000 01 CD S (CD 0-left, 1-right S(hift) 0-no, 1-yes
mijimy 0:3fad116e266c 71 cls();
mijimy 0:3fad116e266c 72 }
mijimy 0:3fad116e266c 73
mijimy 0:3fad116e266c 74 void TextLCD::character(int column, int row, int c) {
mijimy 0:3fad116e266c 75 int a = address(column, row);
mijimy 0:3fad116e266c 76 writeCommand(a);
mijimy 0:3fad116e266c 77 writeData(c);
mijimy 0:3fad116e266c 78 }
mijimy 0:3fad116e266c 79
mijimy 0:3fad116e266c 80 void TextLCD::cls() {
mijimy 0:3fad116e266c 81 writeCommand(0x01); // cls, and set cursor to 0
mijimy 0:3fad116e266c 82 wait(0.00164f); // This command takes 1.64 ms
mijimy 0:3fad116e266c 83 locate(0, 0);
mijimy 0:3fad116e266c 84 }
mijimy 0:3fad116e266c 85
mijimy 0:3fad116e266c 86 void TextLCD::locate(int column, int row) {
mijimy 0:3fad116e266c 87 _column = column;
mijimy 0:3fad116e266c 88 _row = row;
mijimy 0:3fad116e266c 89 }
mijimy 0:3fad116e266c 90
mijimy 0:3fad116e266c 91 int TextLCD::_putc(int value) {
mijimy 0:3fad116e266c 92 if (value == '\n') {
mijimy 0:3fad116e266c 93 _column = 0;
mijimy 0:3fad116e266c 94 _row++;
mijimy 0:3fad116e266c 95 if (_row >= rows()) {
mijimy 0:3fad116e266c 96 _row = 0;
mijimy 0:3fad116e266c 97 }
mijimy 0:3fad116e266c 98 } else {
mijimy 0:3fad116e266c 99 character(_column, _row, value);
mijimy 0:3fad116e266c 100 _column++;
mijimy 0:3fad116e266c 101 if (_column >= columns()) {
mijimy 0:3fad116e266c 102 _column = 0;
mijimy 0:3fad116e266c 103 _row++;
mijimy 0:3fad116e266c 104 if (_row >= rows()) {
mijimy 0:3fad116e266c 105 _row = 0;
mijimy 0:3fad116e266c 106 }
mijimy 0:3fad116e266c 107 }
mijimy 0:3fad116e266c 108 }
mijimy 0:3fad116e266c 109 return value;
mijimy 0:3fad116e266c 110 }
mijimy 0:3fad116e266c 111
mijimy 0:3fad116e266c 112 int TextLCD::_getc() {
mijimy 0:3fad116e266c 113 return -1;
mijimy 0:3fad116e266c 114 }
mijimy 0:3fad116e266c 115
mijimy 0:3fad116e266c 116 void TextLCD::writeI2CByte(int data) {
mijimy 0:3fad116e266c 117 // equivalent to writeI2CByte
mijimy 0:3fad116e266c 118 char cmd[1];
mijimy 0:3fad116e266c 119 cmd[0] = data;
mijimy 0:3fad116e266c 120 _i2c.write(_i2cAddress, cmd, 1);
mijimy 0:3fad116e266c 121 }
mijimy 0:3fad116e266c 122
mijimy 0:3fad116e266c 123 void TextLCD::writeNibble(int data, bool rs) {
mijimy 0:3fad116e266c 124 data = data << 4;
mijimy 0:3fad116e266c 125 data |= BL_ON; // E on
mijimy 0:3fad116e266c 126 if (rs) {
mijimy 0:3fad116e266c 127 data = data | RS_ON; // set rs bit
mijimy 0:3fad116e266c 128 }
mijimy 0:3fad116e266c 129 data |= E_ON; // E on
mijimy 0:3fad116e266c 130 writeI2CByte(data);
mijimy 0:3fad116e266c 131 data ^= E_ON; // E off
mijimy 0:3fad116e266c 132 writeI2CByte(data);
mijimy 0:3fad116e266c 133
mijimy 0:3fad116e266c 134 }
mijimy 0:3fad116e266c 135
mijimy 0:3fad116e266c 136 void TextLCD::writeByte(int data, bool rs) {
mijimy 0:3fad116e266c 137 writeNibble(data >> 4, rs);
mijimy 0:3fad116e266c 138 writeNibble(data & 0x0F, rs);
mijimy 0:3fad116e266c 139 }
mijimy 0:3fad116e266c 140
mijimy 0:3fad116e266c 141 void TextLCD::writeCommand(int command) {
mijimy 0:3fad116e266c 142 // equivalent to ard commandWrite
mijimy 0:3fad116e266c 143 writeByte(command, false);
mijimy 0:3fad116e266c 144 }
mijimy 0:3fad116e266c 145
mijimy 0:3fad116e266c 146 void TextLCD::writeData(int data) {
mijimy 0:3fad116e266c 147
mijimy 0:3fad116e266c 148 writeByte(data, true);
mijimy 0:3fad116e266c 149 }
mijimy 0:3fad116e266c 150
mijimy 0:3fad116e266c 151 int TextLCD::address(int column, int row) {
mijimy 0:3fad116e266c 152 switch (_type) {
mijimy 0:3fad116e266c 153 case LCD20x4:
mijimy 0:3fad116e266c 154 switch (row) {
mijimy 0:3fad116e266c 155 case 0:
mijimy 0:3fad116e266c 156 return 0x80 + column;
mijimy 0:3fad116e266c 157 case 1:
mijimy 0:3fad116e266c 158 return 0xc0 + column;
mijimy 0:3fad116e266c 159 case 2:
mijimy 0:3fad116e266c 160 return 0x94 + column;
mijimy 0:3fad116e266c 161 case 3:
mijimy 0:3fad116e266c 162 return 0xd4 + column;
mijimy 0:3fad116e266c 163 }
mijimy 0:3fad116e266c 164 case LCD16x2B:
mijimy 0:3fad116e266c 165 return 0x80 + (row * 40) + column;
mijimy 0:3fad116e266c 166 case LCD16x2:
mijimy 0:3fad116e266c 167 case LCD20x2:
mijimy 0:3fad116e266c 168 default:
mijimy 0:3fad116e266c 169 return 0x80 + (row * 0x40) + column;
mijimy 0:3fad116e266c 170 }
mijimy 0:3fad116e266c 171 }
mijimy 0:3fad116e266c 172
mijimy 0:3fad116e266c 173 int TextLCD::columns() {
mijimy 0:3fad116e266c 174 switch (_type) {
mijimy 0:3fad116e266c 175 case LCD20x4:
mijimy 0:3fad116e266c 176 case LCD20x2:
mijimy 0:3fad116e266c 177 return 20;
mijimy 0:3fad116e266c 178 case LCD16x2:
mijimy 0:3fad116e266c 179 case LCD16x2B:
mijimy 0:3fad116e266c 180 default:
mijimy 0:3fad116e266c 181 return 16;
mijimy 0:3fad116e266c 182 }
mijimy 0:3fad116e266c 183 }
mijimy 0:3fad116e266c 184
mijimy 0:3fad116e266c 185 int TextLCD::rows() {
mijimy 0:3fad116e266c 186 switch (_type) {
mijimy 0:3fad116e266c 187 case LCD20x4:
mijimy 0:3fad116e266c 188 return 4;
mijimy 0:3fad116e266c 189 case LCD16x2:
mijimy 0:3fad116e266c 190 case LCD16x2B:
mijimy 0:3fad116e266c 191 case LCD20x2:
mijimy 0:3fad116e266c 192 default:
mijimy 0:3fad116e266c 193 return 2;
mijimy 0:3fad116e266c 194 }
mijimy 0:3fad116e266c 195 }