Diff: TextLCD.cpp

Revision:

1:ac48b187213c

Parent:

0:edfb85c53631

Child:

2:227356c7d12c

diff -r edfb85c53631 -r ac48b187213c TextLCD.cpp
--- a/TextLCD.cpp	Sat May 22 18:18:19 2010 +0000
+++ b/TextLCD.cpp	Thu May 27 13:44:15 2010 +0000
@@ -1,115 +1,186 @@
-/* mbed TextLCD Library, 4-bit 2x16
- * Copyright (c) 2007-2010, sford
- *
- * 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"
-
-/*
- * useful info found at http://www.a-netz.de/lcd.en.php
- *
- * Initialisation
- * ==============
- *
- * After attaching the supply voltage/after a reset, the display needs to be brought in to a defined state
- *
- * - wait approximately 15 ms so the display is ready to execute commands
- * - Execute the command 0x30 ("Display Settings") three times (wait 1,64ms after each command, the busy flag cannot be queried now). 
- * - 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.
- * - If you want to use the 4 bit mode, now you can execute the command to switch over to this mode now.
- * - Execute the "clear display" command
- *
- * Timing
- * ======
- *
- * Nearly all commands transmitted to the display need 40us for execution. 
- * Exceptions are the commands "Clear Display and Reset" and "Set Cursor to Start Position" 
- * These commands need 1.64ms for execution. These timings are valid for all displays working with an 
- * internal clock of 250kHz. But I do not know any displays that use other frequencies. Any time you 
- * can use the busy flag to test if the display is ready to accept the next command.
- * 
- * _e is kept high apart from calling clock
- * _rw is kept 0 (write) apart from actions that uyse it differently
- * _rs is set by the data/command writes
- */
-
-TextLCD::TextLCD(PinName rs, PinName rw, PinName e, PinName d0, PinName d1, 
-    PinName d2, PinName d3) : _rw(rw), _rs(rs), 
-    _e(e), _d(d0, d1, d2, d3) {
-
-    _rw = 0;
-    _e  = 1;
-    _rs = 0; // command mode
-
-    // Should theoretically wait 15ms, but most things will be powered up pre-reset
-    // so i'll disable that for the minute. If implemented, could wait 15ms post reset
-    // instead
-    // wait(0.015); 
-        
-    // send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
-    for(int i=0; i<3; i++) {
-        writeByte(0x3);
-        wait(0.00164);      // this command takes 1.64ms, so wait for it
-    }
-    writeByte(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 address = 0x80 + (row * 40) + column; // memory starts at 0x80, and is 40 chars long per row
-      writeCommand(address);           
-      writeData(c); 
-}
-
-int TextLCD::columns() {
-    return 16;
-}
-
-int TextLCD::rows() { 
-    return 2; 
-}
-
-void TextLCD::writeByte(int value) {
-    _d = value >> 4;
-    wait(0.000040f); // most instructions take 40us
-    _e = 0;
-    wait(0.000040f);  
-    _e = 1;    
-    _d = value >> 0;
-    wait(0.000040f);
-    _e = 0;
-    wait(0.000040f);  // most instructions take 40us
-    _e = 1;    
-}
-
-void TextLCD::writeCommand(int command) {
-    _rs = 0;
-    writeByte(command);
-}
-
-void TextLCD::writeData(int data) {
-    _rs = 1;
-    writeByte(data);
-}
+/* mbed TextLCD Library, for a 4-bit LCD based on HD44780
+ * Copyright (c) 2007-2010, sford
+ *
+ * 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"
+
+/* useful info found at http://www.a-netz.de/lcd.en.php
+ *
+ * Initialisation
+ * ==============
+ *
+ * After attaching the supply voltage/after a reset, the display needs to be brought in to a defined state
+ *
+ * - wait approximately 15 ms so the display is ready to execute commands
+ * - Execute the command 0x30 ("Display Settings") three times (wait 1,64ms after each command, the busy flag cannot be queried now).
+ * - 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.
+ * - If you want to use the 4 bit mode, now you can execute the command to switch over to this mode now.
+ * - Execute the "clear display" command
+ *
+ * Timing
+ * ======
+ *
+ * Nearly all commands transmitted to the display need 40us for execution.
+ * Exceptions are the commands "Clear Display and Reset" and "Set Cursor to Start Position"
+ * These commands need 1.64ms for execution. These timings are valid for all displays working with an
+ * internal clock of 250kHz. But I do not know any displays that use other frequencies. Any time you
+ * can use the busy flag to test if the display is ready to accept the next command.
+ *
+ * _e is kept high apart from calling clock
+ * _rw is kept 0 (write) apart from actions that uyse it differently
+ * _rs is set by the data/command writes
+ */
+
+TextLCD::TextLCD(PinName rs, PinName e, PinName d0, PinName d1,
+                 PinName d2, PinName d3, LCDType type) : _rs(rs),
+        _e(e), _d(d0, d1, d2, d3),
+        _type(type) {
+
+    _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++) {
+        writeByte(0x3);
+        wait(0.00164);  // this command takes 1.64ms, so wait for it
+    }
+    writeByte(0x2);     // 4-bit mode
+    wait(0.000040f);    // most instructions take 40us
+
+    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) {
+    _d = value >> 4;
+    wait(0.000040f); // most instructions take 40us
+    _e = 0;
+    wait(0.000040f);
+    _e = 1;
+    _d = value >> 0;
+    wait(0.000040f);
+    _e = 0;
+    wait(0.000040f);  // most instructions take 40us
+    _e = 1;
+}
+
+void TextLCD::writeCommand(int command) {
+    _rs = 0;
+    writeByte(command);
+}
+
+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 * 0x40) + column;
+        case LCD16x2:
+        case LCD20x2:
+        default:
+            return 0x80 + (row * 40) + 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;
+    }
+}