File content as of revision 0:dabc223d3e03:
/* 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 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 * 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;
}
}