Example of using a GDM2004D LCD with Elmicro\'s TestBed for mbed carrier board. Uses an altered version of the TextLCD-library.
Revision 0:7c694e032688, committed 2011-10-11
- Comitter:
- elmicro
- Date:
- Tue Oct 11 08:13:19 2011 +0000
- Commit message:
- Initial Revision
Changed in this revision
diff -r 000000000000 -r 7c694e032688 TextLCD/TextLCD.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/TextLCD/TextLCD.cpp Tue Oct 11 08:13:19 2011 +0000 @@ -0,0 +1,164 @@ +/* mbed TextLCD Library, for a 4-bit LCD based on HD44780 + * Copyright (c) 2007-2010, sford, http://mbed.org + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "TextLCD.h" +#include "mbed.h" + +TextLCD::TextLCD(PinName rs, PinName rw, PinName e, PinName d4, PinName d5, + PinName d6, PinName d7, LCDType type) : _rs(rs), _rw(rw), + _e(e), _d(d4, d5, d6, d7), + _type(type) { + + _rw = 0; + _e = 1; + _rs = 0; // command mode + + wait(0.015); // Wait 15ms to ensure powered up + + // send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus) + for (int i=0; i<3; i++) { + writeNibble(0x3); + wait(0.00164); // this command takes 1.64ms, so wait for it + } + + writeNibble(0x2); // 4-bit mode + + writeCommand(0x28); // Function set 001 BW N F - - + writeCommand(0x0C); + writeCommand(0x6); // Cursor Direction and Display Shift : 0000 01 CD S (CD 0-left, 1-right S(hift) 0-no, 1-yes + cls(); +} + +void TextLCD::character(int column, int row, int c) { + int a = address(column, row); + writeCommand(a); + writeData(c); +} + +void TextLCD::cls() { + writeCommand(0x01); // cls, and set cursor to 0 + wait(0.00164f); // This command takes 1.64 ms + locate(0, 0); +} + +void TextLCD::locate(int column, int row) { + _column = column; + _row = row; +} + +int TextLCD::_putc(int value) { + if (value == '\n') { + _column = 0; + _row++; + if (_row >= rows()) { + _row = 0; + } + } else { + character(_column, _row, value); + _column++; + if (_column >= columns()) { + _column = 0; + _row++; + if (_row >= rows()) { + _row = 0; + } + } + } + return value; +} + +int TextLCD::_getc() { + return -1; +} + +void TextLCD::writeByte(int value) { + writeNibble(value >> 4); + writeNibble(value >> 0); +} + +void TextLCD::writeCommand(int command) { + _rs = 0; + writeByte(command); +} + +void TextLCD::clock(void) { + wait(0.000040f); + _e = 0; + wait(0.000040f); + _e = 1; +} + +void TextLCD::writeNibble(int data) { + _d = data; + clock(); +} + +void TextLCD::writeData(int data) { + _rs = 1; + writeByte(data); +} + +int TextLCD::address(int column, int row) { + switch (_type) { + case LCD20x4: + switch (row) { + case 0: + return 0x80 + column; + case 1: + return 0xc0 + column; + case 2: + return 0x94 + column; + case 3: + return 0xd4 + column; + } + case LCD16x2B: + return 0x80 + (row * 40) + column; + case LCD16x2: + case LCD20x2: + default: + return 0x80 + (row * 0x40) + column; + } +} + +int TextLCD::columns() { + switch (_type) { + case LCD20x4: + case LCD20x2: + return 20; + case LCD16x2: + case LCD16x2B: + default: + return 16; + } +} + +int TextLCD::rows() { + switch (_type) { + case LCD20x4: + return 4; + case LCD16x2: + case LCD16x2B: + case LCD20x2: + default: + return 2; + } +}
diff -r 000000000000 -r 7c694e032688 TextLCD/TextLCD.h --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/TextLCD/TextLCD.h Tue Oct 11 08:13:19 2011 +0000 @@ -0,0 +1,113 @@ +/* mbed TextLCD Library, for a 4-bit LCD based on HD44780 + * Copyright (c) 2007-2010, sford, http://mbed.org + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#ifndef MBED_TEXTLCD_H +#define MBED_TEXTLCD_H + +#include "mbed.h" + +/** A TextLCD interface for driving 4-bit HD44780-based LCDs + * + * Currently supports 16x2, 20x2 and 20x4 panels + * + * @code + * #include "mbed.h" + * #include "TextLCD.h" + * + * TextLCD lcd(p10, p12, p15, p16, p29, p30); // rs, e, d4-d7 + * + * int main() { + * lcd.printf("Hello World!\n"); + * } + * @endcode + */ +class TextLCD : public Stream { +public: + + /** LCD panel format */ + enum LCDType { + LCD16x2 /**< 16x2 LCD panel (default) */ + , LCD16x2B /**< 16x2 LCD panel alternate addressing */ + , LCD20x2 /**< 20x2 LCD panel */ + , LCD20x4 /**< 20x4 LCD panel */ + }; + + /** Create a TextLCD interface + * + * @param rs Instruction/data control line + * @param e Enable line (clock) + * @param d4-d7 Data lines for using as a 4-bit interface + * @param type Sets the panel size/addressing mode (default = LCD16x2) + */ + TextLCD(PinName rs, PinName rw, PinName e, PinName d4, PinName d5, PinName d6, PinName d7, LCDType type = LCD16x2); + +#if DOXYGEN_ONLY + /** Write a character to the LCD + * + * @param c The character to write to the display + */ + int putc(int c); + + /** Write a formated string to the LCD + * + * @param format A printf-style format string, followed by the + * variables to use in formating the string. + */ + int printf(const char* format, ...); +#endif + + /** Locate to a screen column and row + * + * @param column The horizontal position from the left, indexed from 0 + * @param row The vertical position from the top, indexed from 0 + */ + void locate(int column, int row); + + /** Clear the screen and locate to 0,0 */ + void cls(); + + int rows(); + int columns(); + +protected: + + // Stream implementation functions + virtual int _putc(int value); + virtual int _getc(); + + int address(int column, int row); + void character(int column, int row, int c); + void writeByte(int value); + void writeCommand(int command); + void writeData(int data); + void writeNibble(int data); + void clock(void); + + DigitalOut _rs, _rw, _e; + BusOut _d; + LCDType _type; + + int _column; + int _row; +}; + +#endif
diff -r 000000000000 -r 7c694e032688 main.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/main.cpp Tue Oct 11 08:13:19 2011 +0000 @@ -0,0 +1,32 @@ +#include "mbed.h" +//the library "TextLCD.h" was slightly altered to work with the GDM2004D LCD +#include "TextLCD.h" + +//the object "lcd" is initialized to act as a TextLCD with 20x4 characters +TextLCD lcd(p26, p25, p24, p23, p22, p20, p19, TextLCD::LCD20x4); + +int main() { + //each line of the LCD can be accessed directly using the .locate(column, line) function + lcd.locate(0,0); + lcd.printf("12345678901234567890"); + lcd.locate(0,1); + lcd.printf("UVWXYZabcdefghijklmn"); + lcd.locate(0,2); + lcd.printf("ABCDEFGHIJKLMNOPQRST"); + lcd.locate(0,3); + lcd.printf("12345678901234567890"); + wait(2); + + //the LCD is cleared using function .cls() + lcd.cls(); + //a "\n" in a text string causes a line feed + lcd.printf("HELLO WORLD\n"); + //if the end of a line is reached, the text is written to the next line automatically + lcd.printf("Testbed for mbed\nLCD example softwarewith altered library"); + + //the endless loop keeps mbed in low power mode + while(1) + { + __WFI(); + } +}
diff -r 000000000000 -r 7c694e032688 mbed.bld --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Tue Oct 11 08:13:19 2011 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed/builds/029aa53d7323