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TextLCD.cpp@0:7dd9751172e1, 2011-08-03 (annotated)

Committer:: benyun
Date:: Wed Aug 03 00:44:54 2011 +0000
Revision:: 0:7dd9751172e1

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User	Revision	Line number	New contents of line
benyun	0:7dd9751172e1	1	/* mbed TextLCD Library, for a 4-bit LCD based on HD44780
benyun	0:7dd9751172e1	2	* Copyright (c) 2007-2010, sford, http://mbed.org
benyun	0:7dd9751172e1	3	*
benyun	0:7dd9751172e1	4	* Permission is hereby granted, free of charge, to any person obtaining a copy
benyun	0:7dd9751172e1	5	* of this software and associated documentation files (the "Software"), to deal
benyun	0:7dd9751172e1	6	* in the Software without restriction, including without limitation the rights
benyun	0:7dd9751172e1	7	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
benyun	0:7dd9751172e1	8	* copies of the Software, and to permit persons to whom the Software is
benyun	0:7dd9751172e1	9	* furnished to do so, subject to the following conditions:
benyun	0:7dd9751172e1	10	*
benyun	0:7dd9751172e1	11	* The above copyright notice and this permission notice shall be included in
benyun	0:7dd9751172e1	12	* all copies or substantial portions of the Software.
benyun	0:7dd9751172e1	13	*
benyun	0:7dd9751172e1	14	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
benyun	0:7dd9751172e1	15	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
benyun	0:7dd9751172e1	16	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
benyun	0:7dd9751172e1	17	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
benyun	0:7dd9751172e1	18	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
benyun	0:7dd9751172e1	19	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
benyun	0:7dd9751172e1	20	* THE SOFTWARE.
benyun	0:7dd9751172e1	21	*/
benyun	0:7dd9751172e1	22
benyun	0:7dd9751172e1	23	#include "TextLCD.h"
benyun	0:7dd9751172e1	24	#include "mbed.h"
benyun	0:7dd9751172e1	25
benyun	0:7dd9751172e1	26	TextLCD::TextLCD(PinName rs, PinName e, PinName d4, PinName d5,
benyun	0:7dd9751172e1	27	PinName d6, PinName d7, LCDType type) : _rs(rs),
benyun	0:7dd9751172e1	28	_e(e), _d(d4, d5, d6, d7),
benyun	0:7dd9751172e1	29	_type(type) {
benyun	0:7dd9751172e1	30
benyun	0:7dd9751172e1	31	_e = 1;
benyun	0:7dd9751172e1	32	_rs = 0; // command mode
benyun	0:7dd9751172e1	33
benyun	0:7dd9751172e1	34	wait(0.015); // Wait 15ms to ensure powered up
benyun	0:7dd9751172e1	35
benyun	0:7dd9751172e1	36	// send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
benyun	0:7dd9751172e1	37	for (int i=0; i<3; i++) {
benyun	0:7dd9751172e1	38	writeByte(0x3);
benyun	0:7dd9751172e1	39	wait(0.00164); // this command takes 1.64ms, so wait for it
benyun	0:7dd9751172e1	40	}
benyun	0:7dd9751172e1	41	writeByte(0x2); // 4-bit mode
benyun	0:7dd9751172e1	42	wait(0.000040f); // most instructions take 40us
benyun	0:7dd9751172e1	43
benyun	0:7dd9751172e1	44	writeCommand(0x28); // Function set 001 BW N F - -
benyun	0:7dd9751172e1	45	writeCommand(0x0C);
benyun	0:7dd9751172e1	46	writeCommand(0x6); // Cursor Direction and Display Shift : 0000 01 CD S (CD 0-left, 1-right S(hift) 0-no, 1-yes
benyun	0:7dd9751172e1	47	cls();
benyun	0:7dd9751172e1	48	}
benyun	0:7dd9751172e1	49
benyun	0:7dd9751172e1	50	void TextLCD::character(int column, int row, int c) {
benyun	0:7dd9751172e1	51	int a = address(column, row);
benyun	0:7dd9751172e1	52	writeCommand(a);
benyun	0:7dd9751172e1	53	writeData(c);
benyun	0:7dd9751172e1	54	}
benyun	0:7dd9751172e1	55
benyun	0:7dd9751172e1	56	void TextLCD::cls() {
benyun	0:7dd9751172e1	57	writeCommand(0x01); // cls, and set cursor to 0
benyun	0:7dd9751172e1	58	wait(0.00164f); // This command takes 1.64 ms
benyun	0:7dd9751172e1	59	locate(0, 0);
benyun	0:7dd9751172e1	60	}
benyun	0:7dd9751172e1	61
benyun	0:7dd9751172e1	62	void TextLCD::locate(int column, int row) {
benyun	0:7dd9751172e1	63	_column = column;
benyun	0:7dd9751172e1	64	_row = row;
benyun	0:7dd9751172e1	65	}
benyun	0:7dd9751172e1	66
benyun	0:7dd9751172e1	67	int TextLCD::_putc(int value) {
benyun	0:7dd9751172e1	68	if (value == '\n') {
benyun	0:7dd9751172e1	69	_column = 0;
benyun	0:7dd9751172e1	70	_row++;
benyun	0:7dd9751172e1	71	if (_row >= rows()) {
benyun	0:7dd9751172e1	72	_row = 0;
benyun	0:7dd9751172e1	73	}
benyun	0:7dd9751172e1	74	} else {
benyun	0:7dd9751172e1	75	character(_column, _row, value);
benyun	0:7dd9751172e1	76	_column++;
benyun	0:7dd9751172e1	77	if (_column >= columns()) {
benyun	0:7dd9751172e1	78	_column = 0;
benyun	0:7dd9751172e1	79	_row++;
benyun	0:7dd9751172e1	80	if (_row >= rows()) {
benyun	0:7dd9751172e1	81	_row = 0;
benyun	0:7dd9751172e1	82	}
benyun	0:7dd9751172e1	83	}
benyun	0:7dd9751172e1	84	}
benyun	0:7dd9751172e1	85	return value;
benyun	0:7dd9751172e1	86	}
benyun	0:7dd9751172e1	87
benyun	0:7dd9751172e1	88	int TextLCD::_getc() {
benyun	0:7dd9751172e1	89	return -1;
benyun	0:7dd9751172e1	90	}
benyun	0:7dd9751172e1	91
benyun	0:7dd9751172e1	92	void TextLCD::writeByte(int value) {
benyun	0:7dd9751172e1	93	_d = value >> 4;
benyun	0:7dd9751172e1	94	wait(0.000040f); // most instructions take 40us
benyun	0:7dd9751172e1	95	_e = 0;
benyun	0:7dd9751172e1	96	wait(0.000040f);
benyun	0:7dd9751172e1	97	_e = 1;
benyun	0:7dd9751172e1	98	_d = value >> 0;
benyun	0:7dd9751172e1	99	wait(0.000040f);
benyun	0:7dd9751172e1	100	_e = 0;
benyun	0:7dd9751172e1	101	wait(0.000040f); // most instructions take 40us
benyun	0:7dd9751172e1	102	_e = 1;
benyun	0:7dd9751172e1	103	}
benyun	0:7dd9751172e1	104
benyun	0:7dd9751172e1	105	void TextLCD::writeCommand(int command) {
benyun	0:7dd9751172e1	106	_rs = 0;
benyun	0:7dd9751172e1	107	writeByte(command);
benyun	0:7dd9751172e1	108	}
benyun	0:7dd9751172e1	109
benyun	0:7dd9751172e1	110	void TextLCD::writeData(int data) {
benyun	0:7dd9751172e1	111	_rs = 1;
benyun	0:7dd9751172e1	112	writeByte(data);
benyun	0:7dd9751172e1	113	}
benyun	0:7dd9751172e1	114
benyun	0:7dd9751172e1	115	int TextLCD::address(int column, int row) {
benyun	0:7dd9751172e1	116	switch (_type) {
benyun	0:7dd9751172e1	117	case LCD20x4:
benyun	0:7dd9751172e1	118	switch (row) {
benyun	0:7dd9751172e1	119	case 0:
benyun	0:7dd9751172e1	120	return 0x80 + column;
benyun	0:7dd9751172e1	121	case 1:
benyun	0:7dd9751172e1	122	return 0xc0 + column;
benyun	0:7dd9751172e1	123	case 2:
benyun	0:7dd9751172e1	124	return 0x94 + column;
benyun	0:7dd9751172e1	125	case 3:
benyun	0:7dd9751172e1	126	return 0xd4 + column;
benyun	0:7dd9751172e1	127	}
benyun	0:7dd9751172e1	128	case LCD16x2B:
benyun	0:7dd9751172e1	129	return 0x80 + (row * 40) + column;
benyun	0:7dd9751172e1	130	case LCD16x2:
benyun	0:7dd9751172e1	131	case LCD20x2:
benyun	0:7dd9751172e1	132	default:
benyun	0:7dd9751172e1	133	return 0x80 + (row * 0x40) + column;
benyun	0:7dd9751172e1	134	}
benyun	0:7dd9751172e1	135	}
benyun	0:7dd9751172e1	136
benyun	0:7dd9751172e1	137	int TextLCD::columns() {
benyun	0:7dd9751172e1	138	switch (_type) {
benyun	0:7dd9751172e1	139	case LCD20x4:
benyun	0:7dd9751172e1	140	case LCD20x2:
benyun	0:7dd9751172e1	141	return 20;
benyun	0:7dd9751172e1	142	case LCD16x2:
benyun	0:7dd9751172e1	143	case LCD16x2B:
benyun	0:7dd9751172e1	144	default:
benyun	0:7dd9751172e1	145	return 16;
benyun	0:7dd9751172e1	146	}
benyun	0:7dd9751172e1	147	}
benyun	0:7dd9751172e1	148
benyun	0:7dd9751172e1	149	int TextLCD::rows() {
benyun	0:7dd9751172e1	150	switch (_type) {
benyun	0:7dd9751172e1	151	case LCD20x4:
benyun	0:7dd9751172e1	152	return 4;
benyun	0:7dd9751172e1	153	case LCD16x2:
benyun	0:7dd9751172e1	154	case LCD16x2B:
benyun	0:7dd9751172e1	155	case LCD20x2:
benyun	0:7dd9751172e1	156	default:
benyun	0:7dd9751172e1	157	return 2;
benyun	0:7dd9751172e1	158	}
benyun	0:7dd9751172e1	159	}

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Type:	Library
Created:	03 Aug 2011
Imports:	967
Forks:	0
Commits:	1
Dependents:	12
Dependencies:	0
Followers:	15

TextLCD.cpp@0:7dd9751172e1, 2011-08-03 (annotated)

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