Example of using a GDM2004D LCD with Elmicro\'s TestBed for mbed carrier board. Uses an altered version of the TextLCD-library.

Dependencies:   mbed

Files at this revision

API Documentation at this revision

Comitter:
elmicro
Date:
Tue Oct 11 08:13:19 2011 +0000
Commit message:
Initial Revision

Changed in this revision

TextLCD/TextLCD.cpp Show annotated file Show diff for this revision Revisions of this file
TextLCD/TextLCD.h Show annotated file Show diff for this revision Revisions of this file
main.cpp Show annotated file Show diff for this revision Revisions of this file
mbed.bld Show annotated file Show diff for this revision Revisions of this file
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