TextLCD - TextLCD library for controlling various LCD panel…

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TextLCD library for controlling various LCD panels based on the HD44780 4-bit interface

TextLCD.cpp@4:bf5b706f8d32, 2010-05-27 (annotated)

Committer:: simon
Date:: Thu May 27 18:03:45 2010 +0000
Revision:: 4:bf5b706f8d32
Parent:: 2:227356c7d12c
Child:: 6:e4cb7ddee0d3

Who changed what in which revision?

User	Revision	Line number	New contents of line
simon	1:ac48b187213c	1	/* mbed TextLCD Library, for a 4-bit LCD based on HD44780
simon	1:ac48b187213c	2	* Copyright (c) 2007-2010, sford
simon	1:ac48b187213c	3	*
simon	1:ac48b187213c	4	* Permission is hereby granted, free of charge, to any person obtaining a copy
simon	1:ac48b187213c	5	* of this software and associated documentation files (the "Software"), to deal
simon	1:ac48b187213c	6	* in the Software without restriction, including without limitation the rights
simon	1:ac48b187213c	7	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
simon	1:ac48b187213c	8	* copies of the Software, and to permit persons to whom the Software is
simon	1:ac48b187213c	9	* furnished to do so, subject to the following conditions:
simon	1:ac48b187213c	10	*
simon	1:ac48b187213c	11	* The above copyright notice and this permission notice shall be included in
simon	1:ac48b187213c	12	* all copies or substantial portions of the Software.
simon	1:ac48b187213c	13	*
simon	1:ac48b187213c	14	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
simon	1:ac48b187213c	15	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
simon	1:ac48b187213c	16	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
simon	1:ac48b187213c	17	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
simon	1:ac48b187213c	18	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
simon	1:ac48b187213c	19	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
simon	1:ac48b187213c	20	* THE SOFTWARE.
simon	1:ac48b187213c	21	*/
simon	1:ac48b187213c	22
simon	1:ac48b187213c	23	#include "TextLCD.h"
simon	1:ac48b187213c	24	#include "mbed.h"
simon	1:ac48b187213c	25
simon	1:ac48b187213c	26	TextLCD::TextLCD(PinName rs, PinName e, PinName d0, PinName d1,
simon	1:ac48b187213c	27	PinName d2, PinName d3, LCDType type) : _rs(rs),
simon	1:ac48b187213c	28	_e(e), _d(d0, d1, d2, d3),
simon	1:ac48b187213c	29	_type(type) {
simon	1:ac48b187213c	30
simon	1:ac48b187213c	31	_e = 1;
simon	1:ac48b187213c	32	_rs = 0; // command mode
simon	1:ac48b187213c	33
simon	1:ac48b187213c	34	wait(0.015); // Wait 15ms to ensure powered up
simon	1:ac48b187213c	35
simon	1:ac48b187213c	36	// send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
simon	1:ac48b187213c	37	for (int i=0; i<3; i++) {
simon	1:ac48b187213c	38	writeByte(0x3);
simon	1:ac48b187213c	39	wait(0.00164); // this command takes 1.64ms, so wait for it
simon	1:ac48b187213c	40	}
simon	1:ac48b187213c	41	writeByte(0x2); // 4-bit mode
simon	1:ac48b187213c	42	wait(0.000040f); // most instructions take 40us
simon	1:ac48b187213c	43
simon	1:ac48b187213c	44	writeCommand(0x28); // Function set 001 BW N F - -
simon	1:ac48b187213c	45	writeCommand(0x0C);
simon	1:ac48b187213c	46	writeCommand(0x6); // Cursor Direction and Display Shift : 0000 01 CD S (CD 0-left, 1-right S(hift) 0-no, 1-yes
simon	1:ac48b187213c	47	cls();
simon	1:ac48b187213c	48	}
simon	1:ac48b187213c	49
simon	1:ac48b187213c	50	void TextLCD::character(int column, int row, int c) {
simon	1:ac48b187213c	51	int a = address(column, row);
simon	1:ac48b187213c	52	writeCommand(a);
simon	1:ac48b187213c	53	writeData(c);
simon	1:ac48b187213c	54	}
simon	1:ac48b187213c	55
simon	1:ac48b187213c	56	void TextLCD::cls() {
simon	1:ac48b187213c	57	writeCommand(0x01); // cls, and set cursor to 0
simon	1:ac48b187213c	58	wait(0.00164f); // This command takes 1.64 ms
simon	1:ac48b187213c	59	locate(0, 0);
simon	1:ac48b187213c	60	}
simon	1:ac48b187213c	61
simon	1:ac48b187213c	62	void TextLCD::locate(int column, int row) {
simon	1:ac48b187213c	63	_column = column;
simon	1:ac48b187213c	64	_row = row;
simon	1:ac48b187213c	65	}
simon	1:ac48b187213c	66
simon	1:ac48b187213c	67	int TextLCD::_putc(int value) {
simon	1:ac48b187213c	68	if (value == '\n') {
simon	1:ac48b187213c	69	_column = 0;
simon	1:ac48b187213c	70	_row++;
simon	1:ac48b187213c	71	if (_row >= rows()) {
simon	1:ac48b187213c	72	_row = 0;
simon	1:ac48b187213c	73	}
simon	1:ac48b187213c	74	} else {
simon	1:ac48b187213c	75	character(_column, _row, value);
simon	1:ac48b187213c	76	_column++;
simon	1:ac48b187213c	77	if (_column >= columns()) {
simon	1:ac48b187213c	78	_column = 0;
simon	1:ac48b187213c	79	_row++;
simon	1:ac48b187213c	80	if (_row >= rows()) {
simon	1:ac48b187213c	81	_row = 0;
simon	1:ac48b187213c	82	}
simon	1:ac48b187213c	83	}
simon	1:ac48b187213c	84	}
simon	1:ac48b187213c	85	return value;
simon	1:ac48b187213c	86	}
simon	1:ac48b187213c	87
simon	1:ac48b187213c	88	int TextLCD::_getc() {
simon	1:ac48b187213c	89	return -1;
simon	1:ac48b187213c	90	}
simon	1:ac48b187213c	91
simon	1:ac48b187213c	92	void TextLCD::writeByte(int value) {
simon	1:ac48b187213c	93	_d = value >> 4;
simon	1:ac48b187213c	94	wait(0.000040f); // most instructions take 40us
simon	1:ac48b187213c	95	_e = 0;
simon	1:ac48b187213c	96	wait(0.000040f);
simon	1:ac48b187213c	97	_e = 1;
simon	1:ac48b187213c	98	_d = value >> 0;
simon	1:ac48b187213c	99	wait(0.000040f);
simon	1:ac48b187213c	100	_e = 0;
simon	1:ac48b187213c	101	wait(0.000040f); // most instructions take 40us
simon	1:ac48b187213c	102	_e = 1;
simon	1:ac48b187213c	103	}
simon	1:ac48b187213c	104
simon	1:ac48b187213c	105	void TextLCD::writeCommand(int command) {
simon	1:ac48b187213c	106	_rs = 0;
simon	1:ac48b187213c	107	writeByte(command);
simon	1:ac48b187213c	108	}
simon	1:ac48b187213c	109
simon	1:ac48b187213c	110	void TextLCD::writeData(int data) {
simon	1:ac48b187213c	111	_rs = 1;
simon	1:ac48b187213c	112	writeByte(data);
simon	1:ac48b187213c	113	}
simon	1:ac48b187213c	114
simon	1:ac48b187213c	115	int TextLCD::address(int column, int row) {
simon	1:ac48b187213c	116	switch (_type) {
simon	1:ac48b187213c	117	case LCD20x4:
simon	1:ac48b187213c	118	switch (row) {
simon	1:ac48b187213c	119	case 0:
simon	1:ac48b187213c	120	return 0x80 + column;
simon	1:ac48b187213c	121	case 1:
simon	1:ac48b187213c	122	return 0xc0 + column;
simon	1:ac48b187213c	123	case 2:
simon	1:ac48b187213c	124	return 0x94 + column;
simon	1:ac48b187213c	125	case 3:
simon	1:ac48b187213c	126	return 0xd4 + column;
simon	1:ac48b187213c	127	}
simon	1:ac48b187213c	128	case LCD16x2B:
simon	4:bf5b706f8d32	129	return 0x80 + (row * 40) + column;
simon	1:ac48b187213c	130	case LCD16x2:
simon	1:ac48b187213c	131	case LCD20x2:
simon	1:ac48b187213c	132	default:
simon	4:bf5b706f8d32	133	return 0x80 + (row * 0x40) + column;
simon	1:ac48b187213c	134	}
simon	1:ac48b187213c	135	}
simon	1:ac48b187213c	136
simon	1:ac48b187213c	137	int TextLCD::columns() {
simon	1:ac48b187213c	138	switch (_type) {
simon	1:ac48b187213c	139	case LCD20x4:
simon	1:ac48b187213c	140	case LCD20x2:
simon	1:ac48b187213c	141	return 20;
simon	1:ac48b187213c	142	case LCD16x2:
simon	1:ac48b187213c	143	case LCD16x2B:
simon	1:ac48b187213c	144	default:
simon	1:ac48b187213c	145	return 16;
simon	1:ac48b187213c	146	}
simon	1:ac48b187213c	147	}
simon	1:ac48b187213c	148
simon	1:ac48b187213c	149	int TextLCD::rows() {
simon	1:ac48b187213c	150	switch (_type) {
simon	1:ac48b187213c	151	case LCD20x4:
simon	1:ac48b187213c	152	return 4;
simon	1:ac48b187213c	153	case LCD16x2:
simon	1:ac48b187213c	154	case LCD16x2B:
simon	1:ac48b187213c	155	case LCD20x2:
simon	1:ac48b187213c	156	default:
simon	1:ac48b187213c	157	return 2;
simon	1:ac48b187213c	158	}
simon	1:ac48b187213c	159	}

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Type:	Library
Created:	21 Jun 2020
Imports:	6
Forks:	0
Commits:	9
Dependents:	0
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Followers:	1

TextLCD.cpp@4:bf5b706f8d32, 2010-05-27 (annotated)

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