Diff: cryst_lcd.cpp

Revision:

12:5cb9ffad1ad7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cryst_lcd.cpp	Fri May 06 13:10:20 2016 +0000
@@ -0,0 +1,247 @@
+/**
+ * Driver for LCD devices based on the HD44780 controller
+ */
+
+/* Description
+
+LCD SIZES SUPPORTED:
+1-line displays: 8x1, 16x1, 20x1, 24x1, 32x1, 40x1
+2-line displays: 16x2, 20x2, 24x2, 32x2, 40x2
+4-line displays: 16x4, 20x4, 40x4
+
+SUPPORTED PLATFORM: mbed
+*/
+
+
+#include "cryst_lcd.h"
+
+Cryst_LCD::Cryst_LCD(PinName rs, PinName en, PinName db4, PinName db5,
+                     PinName db6, PinName db7, LCDSize size)
+    : _rs(rs), _en(en), _data(db4, db5, db6, db7)
+{
+    _size = size;
+    _row = 0;
+    _col = 0;
+    _displayStatus = 0x0C;
+    init();
+}
+
+
+void Cryst_LCD::cls()
+{
+    writeCommand(0x01, false);
+    wait_ms(2);
+    locate(0, 0);
+}
+
+void Cryst_LCD::locate(int row, int col)
+{
+    _row = 0;
+    _col = col;
+
+    if (row < getMaxRows()) {
+        _row = row;
+    }
+
+    if (_col >= getMaxCols()) {
+        _col = 0;
+        if (_row < getMaxRows() - 1)
+            _row++;
+        else _row = 0;
+    }
+
+    int addr = getAddress(_row, _col);
+    addr |= 0x80;
+    writeCommand(addr);
+}
+
+void Cryst_LCD::display_off() { 
+    _displayStatus &= 0x0B;
+    writeCommand(_displayStatus);
+}
+
+void Cryst_LCD::display_on() {
+    _displayStatus |= 0x04;
+    writeCommand(_displayStatus);
+}
+
+void Cryst_LCD::cursor_on() {
+    _displayStatus |= 0x02;
+    writeCommand(_displayStatus);
+}
+
+void Cryst_LCD::cursor_off() {
+    _displayStatus &= 0x0D;
+    writeCommand(_displayStatus);
+}
+
+void Cryst_LCD::cursor_blink() {
+    _displayStatus |= 0x01;
+    writeCommand(_displayStatus);
+}
+
+void Cryst_LCD::cursor_no_blink() {
+    _displayStatus &= 0x0E;
+    writeCommand(_displayStatus);
+}
+
+void Cryst_LCD::clear_line() {
+    int lineWidth = getMaxCols();
+
+    for (int i = 0; i < lineWidth - 1; i++) {
+        locate(_row, i);
+        printf(" ");
+    }
+
+    locate(_row, 0);
+}
+
+void Cryst_LCD::reset()
+{
+    _rs = 0;
+    wait_ms(15);     // wait approximately 15 ms
+    writeNibble(0x3);  // write config data
+    wait_ms(5);     // wait approximately 4.1 ms
+    writeNibble(0x3);  // write config data again
+    wait_us(100);  // wait approximately 100 us
+}
+
+void Cryst_LCD::init()
+{
+    reset();
+
+    // Function set
+    if (getMaxRows() <= 1) {   // 1-line display
+        // (DF = 0, N = 0, F = 0)
+        // 4-bit mode, 1-line display, 5x8 font size
+        writeCommand(0x20);
+    } else {  // Multi-line display
+        // (DF = 0, N = 1, F = 0)
+        // 4-bit mode, 2-line display, 5x8 font size
+        writeCommand(0x28);
+    }    
+
+    // Entry Mode
+    // (I/D = 1, S = 0)
+    // DDRAM autoincrement, No display shifts
+    writeCommand(0x06);
+
+    // Display Control
+    // (D = 1, C = 0, B = 0)
+    // Display ON, cursor OFF, No cursor blinking
+    writeCommand(_displayStatus);
+
+    // Clear Display
+    cls();
+}
+
+int Cryst_LCD::getAddress(int row, int col)
+{
+    int rowStartAddr[4] = {0x00, 0x40, 0x14, 0x54};
+    int tempRow = 0, tempCol = 0;
+    if (row < getMaxRows()) tempRow = row;
+    if (col < getMaxCols()) tempCol = col;
+    return rowStartAddr[tempRow] + tempCol;
+}
+
+// Default wait time is 40 us
+void Cryst_LCD::writeData(int ch, bool use_default_timing)
+{
+    _rs = 1;
+    writeNibble((ch >> 4) & 0x0F);
+    writeNibble(ch & 0x0F);
+
+    if (use_default_timing)
+        wait_us(40);
+}
+
+// Default wait time is 40 us
+void Cryst_LCD::writeCommand(int cmd, bool use_default_timing)
+{
+    _rs = 0;
+    writeNibble((cmd >> 4) & 0x0F);
+    writeNibble(cmd & 0x0F);
+
+    if (use_default_timing)
+        wait_us(40);
+}
+
+void Cryst_LCD::writeNibble(int nib)
+{
+    _data = nib & 0xF;
+    wait_us(1);
+    _en = 1;
+    wait_us(1);
+    _en = 0;
+    wait_us(1);
+}
+
+void Cryst_LCD::getMaxDimensions(int* rowCount, int* colCount) {
+    switch(_size) {
+        // 1-line displays
+        case LCD8x1:  *rowCount = 1; *colCount = 8;  break;
+        case LCD16x1: *rowCount = 1; *colCount = 16; break;
+        case LCD20x1: *rowCount = 1; *colCount = 20; break;
+        case LCD24x1: *rowCount = 1; *colCount = 24; break;
+        case LCD32x1: *rowCount = 1; *colCount = 32; break;
+        case LCD40x1: *rowCount = 1; *colCount = 40; break;
+
+        // 2-line displays
+        case LCD16x2: *rowCount = 2; *colCount = 16; break;
+        case LCD20x2: *rowCount = 2; *colCount = 20; break;
+        case LCD24x2: *rowCount = 2; *colCount = 24; break;
+        case LCD32x2: *rowCount = 2; *colCount = 32; break;
+        case LCD40x2: *rowCount = 2; *colCount = 40; break;
+
+        // 4-line displays
+        case LCD16x4: *rowCount = 4; *colCount = 16; break;
+        case LCD20x4: *rowCount = 4; *colCount = 20; break;
+        case LCD40x4: *rowCount = 4; *colCount = 40; break;
+
+        default: *rowCount = 0; *colCount = 0; break;
+    }
+}
+
+int Cryst_LCD::getMaxRows()
+{
+    int rowCount = 0;
+    int colCount = 0;
+    getMaxDimensions(&rowCount, &colCount);
+    return rowCount;
+}
+
+int Cryst_LCD::getMaxCols()
+{
+    int rowCount = 0;
+    int colCount = 0;
+    getMaxDimensions(&rowCount, &colCount);
+    return colCount;
+}
+
+int Cryst_LCD::_putc(int ch)
+{
+    if (ch == '\n') {
+        locate(_row + 1, 0);        
+    }
+        
+    else if (ch == '\t') {      
+        locate(_row, _col + 3);
+    } 
+
+    else if (ch == '\r') {  
+        locate(_row, 0);
+    }  
+
+    else {
+        locate(_row, _col);
+        writeData(ch);
+        locate(_row, _col + 1);
+    }
+
+    return ch;
+}
+
+int Cryst_LCD::_getc()
+{
+    return -5;
+}
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