Updated for more display types. Fixed memoryaddress confusion in address() method. Added new getAddress() method. Added support for UDCs, Backlight control and other features such as control through I2C and SPI port expanders and controllers with native I2C and SPI interfaces. Refactored to fix issue with pins that are default declared as NC.
Dependents: GPSDevice TestTextLCD SD to Flash Data Transfer DrumMachine ... more
Fork of TextLCD by
Example
Hello World! for the TextLCD
#include "mbed.h" #include "TextLCD.h" // Host PC Communication channels Serial pc(USBTX, USBRX); // tx, rx // I2C Communication I2C i2c_lcd(p28,p27); // SDA, SCL // SPI Communication SPI spi_lcd(p5, NC, p7); // MOSI, MISO, SCLK //TextLCD lcd(p15, p16, p17, p18, p19, p20); // RS, E, D4-D7, LCDType=LCD16x2, BL=NC, E2=NC, LCDTCtrl=HD44780 //TextLCD_SPI lcd(&spi_lcd, p8, TextLCD::LCD40x4); // SPI bus, 74595 expander, CS pin, LCD Type TextLCD_I2C lcd(&i2c_lcd, 0x42, TextLCD::LCD20x4); // I2C bus, PCF8574 Slaveaddress, LCD Type //TextLCD_I2C lcd(&i2c_lcd, 0x42, TextLCD::LCD16x2, TextLCD::WS0010); // I2C bus, PCF8574 Slaveaddress, LCD Type, Device Type //TextLCD_SPI_N lcd(&spi_lcd, p8, p9); // SPI bus, CS pin, RS pin, LCDType=LCD16x2, BL=NC, LCDTCtrl=ST7032_3V3 //TextLCD_I2C_N lcd(&i2c_lcd, ST7032_SA, TextLCD::LCD16x2, NC, TextLCD::ST7032_3V3); // I2C bus, Slaveaddress, LCD Type, BL=NC, LCDTCtrl=ST7032_3V3 int main() { pc.printf("LCD Test. Columns=%d, Rows=%d\n\r", lcd.columns(), lcd.rows()); for (int row=0; row<lcd.rows(); row++) { int col=0; pc.printf("MemAddr(Col=%d, Row=%d)=0x%02X\n\r", col, row, lcd.getAddress(col, row)); // lcd.putc('-'); lcd.putc('0' + row); for (col=1; col<lcd.columns()-1; col++) { lcd.putc('*'); } pc.printf("MemAddr(Col=%d, Row=%d)=0x%02X\n\r", col, row, lcd.getAddress(col, row)); lcd.putc('+'); } // Show cursor as blinking character lcd.setCursor(TextLCD::CurOff_BlkOn); // Set and show user defined characters. A maximum of 8 UDCs are supported by the HD44780. // They are defined by a 5x7 bitpattern. lcd.setUDC(0, (char *) udc_0); // Show |> lcd.putc(0); lcd.setUDC(1, (char *) udc_1); // Show <| lcd.putc(1); }
Handbook page
More info is here
TextLCD.cpp@1:ac48b187213c, 2010-05-27 (annotated)
- Committer:
- simon
- Date:
- Thu May 27 13:44:15 2010 +0000
- Revision:
- 1:ac48b187213c
- Parent:
- 0:edfb85c53631
- Child:
- 2:227356c7d12c
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
simon | 1:ac48b187213c | 1 | /* mbed TextLCD Library, for a 4-bit LCD based on HD44780 |
simon | 1:ac48b187213c | 2 | * Copyright (c) 2007-2010, sford |
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 | /* useful info found at http://www.a-netz.de/lcd.en.php |
simon | 1:ac48b187213c | 27 | * |
simon | 1:ac48b187213c | 28 | * Initialisation |
simon | 1:ac48b187213c | 29 | * ============== |
simon | 1:ac48b187213c | 30 | * |
simon | 1:ac48b187213c | 31 | * After attaching the supply voltage/after a reset, the display needs to be brought in to a defined state |
simon | 1:ac48b187213c | 32 | * |
simon | 1:ac48b187213c | 33 | * - wait approximately 15 ms so the display is ready to execute commands |
simon | 1:ac48b187213c | 34 | * - Execute the command 0x30 ("Display Settings") three times (wait 1,64ms after each command, the busy flag cannot be queried now). |
simon | 1:ac48b187213c | 35 | * - 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. |
simon | 1:ac48b187213c | 36 | * - If you want to use the 4 bit mode, now you can execute the command to switch over to this mode now. |
simon | 1:ac48b187213c | 37 | * - Execute the "clear display" command |
simon | 1:ac48b187213c | 38 | * |
simon | 1:ac48b187213c | 39 | * Timing |
simon | 1:ac48b187213c | 40 | * ====== |
simon | 1:ac48b187213c | 41 | * |
simon | 1:ac48b187213c | 42 | * Nearly all commands transmitted to the display need 40us for execution. |
simon | 1:ac48b187213c | 43 | * Exceptions are the commands "Clear Display and Reset" and "Set Cursor to Start Position" |
simon | 1:ac48b187213c | 44 | * These commands need 1.64ms for execution. These timings are valid for all displays working with an |
simon | 1:ac48b187213c | 45 | * internal clock of 250kHz. But I do not know any displays that use other frequencies. Any time you |
simon | 1:ac48b187213c | 46 | * can use the busy flag to test if the display is ready to accept the next command. |
simon | 1:ac48b187213c | 47 | * |
simon | 1:ac48b187213c | 48 | * _e is kept high apart from calling clock |
simon | 1:ac48b187213c | 49 | * _rw is kept 0 (write) apart from actions that uyse it differently |
simon | 1:ac48b187213c | 50 | * _rs is set by the data/command writes |
simon | 1:ac48b187213c | 51 | */ |
simon | 1:ac48b187213c | 52 | |
simon | 1:ac48b187213c | 53 | TextLCD::TextLCD(PinName rs, PinName e, PinName d0, PinName d1, |
simon | 1:ac48b187213c | 54 | PinName d2, PinName d3, LCDType type) : _rs(rs), |
simon | 1:ac48b187213c | 55 | _e(e), _d(d0, d1, d2, d3), |
simon | 1:ac48b187213c | 56 | _type(type) { |
simon | 1:ac48b187213c | 57 | |
simon | 1:ac48b187213c | 58 | _e = 1; |
simon | 1:ac48b187213c | 59 | _rs = 0; // command mode |
simon | 1:ac48b187213c | 60 | |
simon | 1:ac48b187213c | 61 | wait(0.015); // Wait 15ms to ensure powered up |
simon | 1:ac48b187213c | 62 | |
simon | 1:ac48b187213c | 63 | // send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus) |
simon | 1:ac48b187213c | 64 | for (int i=0; i<3; i++) { |
simon | 1:ac48b187213c | 65 | writeByte(0x3); |
simon | 1:ac48b187213c | 66 | wait(0.00164); // this command takes 1.64ms, so wait for it |
simon | 1:ac48b187213c | 67 | } |
simon | 1:ac48b187213c | 68 | writeByte(0x2); // 4-bit mode |
simon | 1:ac48b187213c | 69 | wait(0.000040f); // most instructions take 40us |
simon | 1:ac48b187213c | 70 | |
simon | 1:ac48b187213c | 71 | writeCommand(0x28); // Function set 001 BW N F - - |
simon | 1:ac48b187213c | 72 | writeCommand(0x0C); |
simon | 1:ac48b187213c | 73 | 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 | 74 | cls(); |
simon | 1:ac48b187213c | 75 | } |
simon | 1:ac48b187213c | 76 | |
simon | 1:ac48b187213c | 77 | void TextLCD::character(int column, int row, int c) { |
simon | 1:ac48b187213c | 78 | int a = address(column, row); |
simon | 1:ac48b187213c | 79 | writeCommand(a); |
simon | 1:ac48b187213c | 80 | writeData(c); |
simon | 1:ac48b187213c | 81 | } |
simon | 1:ac48b187213c | 82 | |
simon | 1:ac48b187213c | 83 | void TextLCD::cls() { |
simon | 1:ac48b187213c | 84 | writeCommand(0x01); // cls, and set cursor to 0 |
simon | 1:ac48b187213c | 85 | wait(0.00164f); // This command takes 1.64 ms |
simon | 1:ac48b187213c | 86 | locate(0, 0); |
simon | 1:ac48b187213c | 87 | } |
simon | 1:ac48b187213c | 88 | |
simon | 1:ac48b187213c | 89 | void TextLCD::locate(int column, int row) { |
simon | 1:ac48b187213c | 90 | _column = column; |
simon | 1:ac48b187213c | 91 | _row = row; |
simon | 1:ac48b187213c | 92 | } |
simon | 1:ac48b187213c | 93 | |
simon | 1:ac48b187213c | 94 | int TextLCD::_putc(int value) { |
simon | 1:ac48b187213c | 95 | if (value == '\n') { |
simon | 1:ac48b187213c | 96 | _column = 0; |
simon | 1:ac48b187213c | 97 | _row++; |
simon | 1:ac48b187213c | 98 | if (_row >= rows()) { |
simon | 1:ac48b187213c | 99 | _row = 0; |
simon | 1:ac48b187213c | 100 | } |
simon | 1:ac48b187213c | 101 | } else { |
simon | 1:ac48b187213c | 102 | character(_column, _row, value); |
simon | 1:ac48b187213c | 103 | _column++; |
simon | 1:ac48b187213c | 104 | if (_column >= columns()) { |
simon | 1:ac48b187213c | 105 | _column = 0; |
simon | 1:ac48b187213c | 106 | _row++; |
simon | 1:ac48b187213c | 107 | if (_row >= rows()) { |
simon | 1:ac48b187213c | 108 | _row = 0; |
simon | 1:ac48b187213c | 109 | } |
simon | 1:ac48b187213c | 110 | } |
simon | 1:ac48b187213c | 111 | } |
simon | 1:ac48b187213c | 112 | return value; |
simon | 1:ac48b187213c | 113 | } |
simon | 1:ac48b187213c | 114 | |
simon | 1:ac48b187213c | 115 | int TextLCD::_getc() { |
simon | 1:ac48b187213c | 116 | return -1; |
simon | 1:ac48b187213c | 117 | } |
simon | 1:ac48b187213c | 118 | |
simon | 1:ac48b187213c | 119 | void TextLCD::writeByte(int value) { |
simon | 1:ac48b187213c | 120 | _d = value >> 4; |
simon | 1:ac48b187213c | 121 | wait(0.000040f); // most instructions take 40us |
simon | 1:ac48b187213c | 122 | _e = 0; |
simon | 1:ac48b187213c | 123 | wait(0.000040f); |
simon | 1:ac48b187213c | 124 | _e = 1; |
simon | 1:ac48b187213c | 125 | _d = value >> 0; |
simon | 1:ac48b187213c | 126 | wait(0.000040f); |
simon | 1:ac48b187213c | 127 | _e = 0; |
simon | 1:ac48b187213c | 128 | wait(0.000040f); // most instructions take 40us |
simon | 1:ac48b187213c | 129 | _e = 1; |
simon | 1:ac48b187213c | 130 | } |
simon | 1:ac48b187213c | 131 | |
simon | 1:ac48b187213c | 132 | void TextLCD::writeCommand(int command) { |
simon | 1:ac48b187213c | 133 | _rs = 0; |
simon | 1:ac48b187213c | 134 | writeByte(command); |
simon | 1:ac48b187213c | 135 | } |
simon | 1:ac48b187213c | 136 | |
simon | 1:ac48b187213c | 137 | void TextLCD::writeData(int data) { |
simon | 1:ac48b187213c | 138 | _rs = 1; |
simon | 1:ac48b187213c | 139 | writeByte(data); |
simon | 1:ac48b187213c | 140 | } |
simon | 1:ac48b187213c | 141 | |
simon | 1:ac48b187213c | 142 | int TextLCD::address(int column, int row) { |
simon | 1:ac48b187213c | 143 | switch (_type) { |
simon | 1:ac48b187213c | 144 | case LCD20x4: |
simon | 1:ac48b187213c | 145 | switch (row) { |
simon | 1:ac48b187213c | 146 | case 0: |
simon | 1:ac48b187213c | 147 | return 0x80 + column; |
simon | 1:ac48b187213c | 148 | case 1: |
simon | 1:ac48b187213c | 149 | return 0xc0 + column; |
simon | 1:ac48b187213c | 150 | case 2: |
simon | 1:ac48b187213c | 151 | return 0x94 + column; |
simon | 1:ac48b187213c | 152 | case 3: |
simon | 1:ac48b187213c | 153 | return 0xd4 + column; |
simon | 1:ac48b187213c | 154 | } |
simon | 1:ac48b187213c | 155 | case LCD16x2B: |
simon | 1:ac48b187213c | 156 | return 0x80 + (row * 0x40) + column; |
simon | 1:ac48b187213c | 157 | case LCD16x2: |
simon | 1:ac48b187213c | 158 | case LCD20x2: |
simon | 1:ac48b187213c | 159 | default: |
simon | 1:ac48b187213c | 160 | return 0x80 + (row * 40) + column; |
simon | 1:ac48b187213c | 161 | } |
simon | 1:ac48b187213c | 162 | } |
simon | 1:ac48b187213c | 163 | |
simon | 1:ac48b187213c | 164 | int TextLCD::columns() { |
simon | 1:ac48b187213c | 165 | switch (_type) { |
simon | 1:ac48b187213c | 166 | case LCD20x4: |
simon | 1:ac48b187213c | 167 | case LCD20x2: |
simon | 1:ac48b187213c | 168 | return 20; |
simon | 1:ac48b187213c | 169 | case LCD16x2: |
simon | 1:ac48b187213c | 170 | case LCD16x2B: |
simon | 1:ac48b187213c | 171 | default: |
simon | 1:ac48b187213c | 172 | return 16; |
simon | 1:ac48b187213c | 173 | } |
simon | 1:ac48b187213c | 174 | } |
simon | 1:ac48b187213c | 175 | |
simon | 1:ac48b187213c | 176 | int TextLCD::rows() { |
simon | 1:ac48b187213c | 177 | switch (_type) { |
simon | 1:ac48b187213c | 178 | case LCD20x4: |
simon | 1:ac48b187213c | 179 | return 4; |
simon | 1:ac48b187213c | 180 | case LCD16x2: |
simon | 1:ac48b187213c | 181 | case LCD16x2B: |
simon | 1:ac48b187213c | 182 | case LCD20x2: |
simon | 1:ac48b187213c | 183 | default: |
simon | 1:ac48b187213c | 184 | return 2; |
simon | 1:ac48b187213c | 185 | } |
simon | 1:ac48b187213c | 186 | } |