Diff: TextLCD.cpp

Revision:

0:006bcd28cc39

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TextLCD.cpp	Wed Mar 21 23:55:03 2012 +0000
@@ -0,0 +1,226 @@
+/* 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 d0, PinName d1,
+                 PinName d2, PinName d3, LCDType type) : _rs(rs), _rw(rw),
+        _e(e), _d(d0, d1, d2, d3), _type(type) {
+    _rs = 0;            // command mode
+    _rw = 0;
+    _e  = 0;            
+    _d.output();        // data out
+
+    wait(0.05);        // Wait 50ms 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++) {
+        _e = 1;
+        __nop();
+        _d = 0x3;
+        __nop();
+        _e = 0;
+        wait(0.004f); // 4ms
+       }
+    _e = 1;
+    __nop();
+    _d = 0x2;           // 4 Bit mode
+    __nop(); 
+    _e = 0;
+    
+    writeCommand(0x28); // Function set 4 Bit, 2Line, 5*7
+    writeCommand(0x08); // Display off
+    writeCommand(0x01); // clear Display
+    writeCommand(0x04); // cursor right, Display is not shifted
+    writeCommand(0x0C); // Display on , Cursor off 
+}
+
+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
+    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() {
+    int a = address(_column, _row);
+    writeCommand(a);
+    return (readData());
+}
+
+void TextLCD::writeByte(int value) {
+    _e = 1;
+    __nop();    
+    _d = value >> 4;
+    __nop();
+    _e = 0;
+    __nop();
+    _e = 1;
+    __nop();
+    _d = value >> 0;
+    __nop();
+    _e = 0;
+}
+
+void TextLCD::writeCommand(int command) {
+    waitBusy();  // check if display is ready 
+    _rs = 0;
+    writeByte(command);
+}
+
+int TextLCD::readData(){
+    int input;
+    waitBusy();
+    _rw = 1;
+    _rs = 1;
+    __nop();
+    _d.input();  // switch Data port to input
+    _e = 1;
+    __nop();
+    input = _d.read() << 4; // high nibble
+    _e = 0;
+    __nop();
+    _e = 1;
+    __nop();
+    input = input | _d.read(); // low nibble
+    _e = 0;   
+    return (input);
+}
+
+ void TextLCD::waitBusy(){
+    int input;
+    _rw = 1;
+    _rs = 0;
+    __nop();
+    _d.input();      // switch Data port to input
+    do{ 
+        _e = 1;
+        __nop();
+        input = _d.read();              
+        _e = 0;
+        __nop();
+        _e = 1;
+        __nop();
+        _e = 0;
+       }while((0x8 & input) == 0x8);  // wait until display is ready
+    _rw = 0;
+    _d.output();      // switch port back to output  
+ }
+
+void TextLCD::writeData(int data) {
+    waitBusy();
+    _rs = 1;
+    writeByte(data);
+}
+
+
+// set user defined char 
+void  TextLCD::writeCGRAM(int address, int pattern[8]){
+    int i;
+    address = address & 0x07;  //max 8 char
+    for(i=0;i<8;i++){
+        waitBusy();  // check if display is ready 
+        _rs = 0;
+        writeByte(0x40 + address * 8 + i);
+        writeData(pattern[i]);
+        }
+}   
+        
+
+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;
+    }
+}