Nicolas Duchoud
LCD driver
Dependents: host_mouse lcd_keypad_shield TestDeviceIot
Diff: TextLCD.cpp
- Revision:
- 1:19be52262a2d
- Parent:
- 0:ec079a141883
--- a/TextLCD.cpp Fri Jul 27 15:06:59 2012 +0000
+++ b/TextLCD.cpp Fri Jul 26 03:30:12 2019 +0000
@@ -1,151 +1,159 @@
-/* mbed TextLCD Library
- * Copyright (c) 2007-2009 sford
- * Released under the MIT License: http://mbed.org/license/mit
- */
-
-#include "TextLCD.h"
-
-#include "mbed.h"
-#include "error.h"
-
-using namespace mbed;
-
-/*
- * useful info found at http://www.a-netz.de/lcd.en.php
+/* mbed TextLCD Library, for a 4-bit LCD based on HD44780
+ * Copyright (c) 2007-2010, sford, http://mbed.org
*
- *
- * Initialisation
- * ==============
+ * 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:
*
- * 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
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
*
- * 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
+ * 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.
*/
-TextLCD::TextLCD(PinName rs, PinName rw, PinName e, PinName d0, PinName d1,
- PinName d2, PinName d3, int columns, int rows) : _rw(rw), _rs(rs),
- _e(e), _d(d0, d1, d2, d3), _columns(columns), _rows(rows) {
+#include "TextLCD.h"
+#include "mbed.h"
+
+TextLCD::TextLCD(PinName rs, PinName e, PinName d4, PinName d5,
+ PinName d6, PinName d7, LCDType type) : _rs(rs),
+ _e(e), _d(d4, d5, d6, d7),
+ _type(type) {
-// _rows = 2;
-// _columns = 16;
- // Mon, 27 Apr 2009 23:32:34 +0200
- // Kevin Konradt:
- // When using a LCD with 1 row x 16 characters
- // instead of 2x16, try changing _columns to 8.
- // (display seems to split the 16 characters into
- // 2 virtual rows with 8 characters each.)
+ _e = 1;
+ _rs = 0; // command mode
+
+ wait(0.015); // Wait 15ms to ensure powered up
- _rw = 0;
- _e = 1;
- _rs = 0; // command mode
+ // 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
- // 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++) {
- 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();
+ 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') {
- newline();
- } else {
- writeData(value);
- }
- return 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 0;
-}
-
-void TextLCD::newline() {
- _column = 0;
- _row++;
- if(_row >= _rows) {
- _row = 0;
- }
- locate(_column, _row);
-}
-
-void TextLCD::locate(int column, int row) {
- if(column < 0 || column >= _columns || row < 0 || row >= _rows) {
- error("locate(%d,%d) out of range on %dx%d display", column, row, _columns, _rows);
- return;
- }
-
- _row = row;
- _column = column;
- int address = 0x80 + (_row * 40) + _column; // memory starts at 0x80, and is 40 chars long per row
- writeCommand(address);
-}
-
-void TextLCD::cls() {
- writeCommand(0x01); // Clear Display
- wait(0.00164f); // This command takes 1.64 ms
- locate(0, 0);
-}
-
-void TextLCD::reset() {
- cls();
-}
-
-void TextLCD::clock() {
- wait(0.000040f);
- _e = 0;
- wait(0.000040f); // most instructions take 40us
- _e = 1;
-}
-
-void TextLCD::writeNibble(int value) {
- _d = value;
- clock();
+ return -1;
}
void TextLCD::writeByte(int value) {
- writeNibble(value >> 4);
- writeNibble(value >> 0);
+ _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);
+ _rs = 0;
+ writeByte(command);
}
void TextLCD::writeData(int data) {
- _rs = 1;
- writeByte(data);
- _column++;
- if(_column >= _columns) {
- newline();
- }
+ _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;
+ }
+}