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TextLCD.cpp@0:ffeb3e6c1367, 2010-12-21 (annotated)

Committer:: mamezu
Date:: Tue Dec 21 07:20:38 2010 +0000
Revision:: 0:ffeb3e6c1367

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mamezu	0:ffeb3e6c1367	1	/* mbed TextLCD Library, for a 4-bit LCD based on HD44780
mamezu	0:ffeb3e6c1367	2	* Copyright (c) 2007-2010, sford
mamezu	0:ffeb3e6c1367	3	*
mamezu	0:ffeb3e6c1367	4	* Permission is hereby granted, free of charge, to any person obtaining a copy
mamezu	0:ffeb3e6c1367	5	* of this software and associated documentation files (the "Software"), to deal
mamezu	0:ffeb3e6c1367	6	* in the Software without restriction, including without limitation the rights
mamezu	0:ffeb3e6c1367	7	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
mamezu	0:ffeb3e6c1367	8	* copies of the Software, and to permit persons to whom the Software is
mamezu	0:ffeb3e6c1367	9	* furnished to do so, subject to the following conditions:
mamezu	0:ffeb3e6c1367	10	*
mamezu	0:ffeb3e6c1367	11	* The above copyright notice and this permission notice shall be included in
mamezu	0:ffeb3e6c1367	12	* all copies or substantial portions of the Software.
mamezu	0:ffeb3e6c1367	13	*
mamezu	0:ffeb3e6c1367	14	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
mamezu	0:ffeb3e6c1367	15	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
mamezu	0:ffeb3e6c1367	16	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
mamezu	0:ffeb3e6c1367	17	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
mamezu	0:ffeb3e6c1367	18	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
mamezu	0:ffeb3e6c1367	19	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
mamezu	0:ffeb3e6c1367	20	* THE SOFTWARE.
mamezu	0:ffeb3e6c1367	21	*/
mamezu	0:ffeb3e6c1367	22
mamezu	0:ffeb3e6c1367	23	#include "TextLCD.h"
mamezu	0:ffeb3e6c1367	24	#include "mbed.h"
mamezu	0:ffeb3e6c1367	25
mamezu	0:ffeb3e6c1367	26	TextLCD::TextLCD(PinName rs, PinName e, PinName d0, PinName d1,
mamezu	0:ffeb3e6c1367	27	PinName d2, PinName d3, LCDType type) : _rs(rs),
mamezu	0:ffeb3e6c1367	28	_e(e), _d(d0, d1, d2, d3),
mamezu	0:ffeb3e6c1367	29	_type(type) {
mamezu	0:ffeb3e6c1367	30
mamezu	0:ffeb3e6c1367	31	_e = 1;
mamezu	0:ffeb3e6c1367	32	_rs = 0; // command mode
mamezu	0:ffeb3e6c1367	33
mamezu	0:ffeb3e6c1367	34	wait(0.015); // Wait 15ms to ensure powered up
mamezu	0:ffeb3e6c1367	35
mamezu	0:ffeb3e6c1367	36	// send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
mamezu	0:ffeb3e6c1367	37	for (int i=0; i<3; i++) {
mamezu	0:ffeb3e6c1367	38	writeByte(0x3);
mamezu	0:ffeb3e6c1367	39	wait(0.00164); // this command takes 1.64ms, so wait for it
mamezu	0:ffeb3e6c1367	40	}
mamezu	0:ffeb3e6c1367	41	writeByte(0x2); // 4-bit mode
mamezu	0:ffeb3e6c1367	42	wait(0.000040f); // most instructions take 40us
mamezu	0:ffeb3e6c1367	43
mamezu	0:ffeb3e6c1367	44	writeCommand(0x28); // Function set 001 BW N F - -
mamezu	0:ffeb3e6c1367	45	writeCommand(0x0C);
mamezu	0:ffeb3e6c1367	46	writeCommand(0x6); // Cursor Direction and Display Shift : 0000 01 CD S (CD 0-left, 1-right S(hift) 0-no, 1-yes
mamezu	0:ffeb3e6c1367	47	cls();
mamezu	0:ffeb3e6c1367	48	}
mamezu	0:ffeb3e6c1367	49
mamezu	0:ffeb3e6c1367	50	void TextLCD::character(int column, int row, int c) {
mamezu	0:ffeb3e6c1367	51	int a = address(column, row);
mamezu	0:ffeb3e6c1367	52	writeCommand(a);
mamezu	0:ffeb3e6c1367	53	writeData(c);
mamezu	0:ffeb3e6c1367	54	}
mamezu	0:ffeb3e6c1367	55
mamezu	0:ffeb3e6c1367	56	void TextLCD::cls() {
mamezu	0:ffeb3e6c1367	57	writeCommand(0x01); // cls, and set cursor to 0
mamezu	0:ffeb3e6c1367	58	wait(0.00164f); // This command takes 1.64 ms
mamezu	0:ffeb3e6c1367	59	locate(0, 0);
mamezu	0:ffeb3e6c1367	60	}
mamezu	0:ffeb3e6c1367	61
mamezu	0:ffeb3e6c1367	62	void TextLCD::locate(int column, int row) {
mamezu	0:ffeb3e6c1367	63	_column = column;
mamezu	0:ffeb3e6c1367	64	_row = row;
mamezu	0:ffeb3e6c1367	65	}
mamezu	0:ffeb3e6c1367	66
mamezu	0:ffeb3e6c1367	67	int TextLCD::_putc(int value) {
mamezu	0:ffeb3e6c1367	68	if (value == '\n') {
mamezu	0:ffeb3e6c1367	69	_column = 0;
mamezu	0:ffeb3e6c1367	70	_row++;
mamezu	0:ffeb3e6c1367	71	if (_row >= rows()) {
mamezu	0:ffeb3e6c1367	72	_row = 0;
mamezu	0:ffeb3e6c1367	73	}
mamezu	0:ffeb3e6c1367	74	} else {
mamezu	0:ffeb3e6c1367	75	character(_column, _row, value);
mamezu	0:ffeb3e6c1367	76	_column++;
mamezu	0:ffeb3e6c1367	77	if (_column >= columns()) {
mamezu	0:ffeb3e6c1367	78	_column = 0;
mamezu	0:ffeb3e6c1367	79	_row++;
mamezu	0:ffeb3e6c1367	80	if (_row >= rows()) {
mamezu	0:ffeb3e6c1367	81	_row = 0;
mamezu	0:ffeb3e6c1367	82	}
mamezu	0:ffeb3e6c1367	83	}
mamezu	0:ffeb3e6c1367	84	}
mamezu	0:ffeb3e6c1367	85	return value;
mamezu	0:ffeb3e6c1367	86	}
mamezu	0:ffeb3e6c1367	87
mamezu	0:ffeb3e6c1367	88	int TextLCD::_getc() {
mamezu	0:ffeb3e6c1367	89	return -1;
mamezu	0:ffeb3e6c1367	90	}
mamezu	0:ffeb3e6c1367	91
mamezu	0:ffeb3e6c1367	92	void TextLCD::writeByte(int value) {
mamezu	0:ffeb3e6c1367	93	_d = value >> 4;
mamezu	0:ffeb3e6c1367	94	wait(0.000040f); // most instructions take 40us
mamezu	0:ffeb3e6c1367	95	_e = 0;
mamezu	0:ffeb3e6c1367	96	wait(0.000040f);
mamezu	0:ffeb3e6c1367	97	_e = 1;
mamezu	0:ffeb3e6c1367	98	_d = value >> 0;
mamezu	0:ffeb3e6c1367	99	wait(0.000040f);
mamezu	0:ffeb3e6c1367	100	_e = 0;
mamezu	0:ffeb3e6c1367	101	wait(0.000040f); // most instructions take 40us
mamezu	0:ffeb3e6c1367	102	_e = 1;
mamezu	0:ffeb3e6c1367	103	}
mamezu	0:ffeb3e6c1367	104
mamezu	0:ffeb3e6c1367	105	void TextLCD::writeCommand(int command) {
mamezu	0:ffeb3e6c1367	106	_rs = 0;
mamezu	0:ffeb3e6c1367	107	writeByte(command);
mamezu	0:ffeb3e6c1367	108	}
mamezu	0:ffeb3e6c1367	109
mamezu	0:ffeb3e6c1367	110	void TextLCD::writeData(int data) {
mamezu	0:ffeb3e6c1367	111	_rs = 1;
mamezu	0:ffeb3e6c1367	112	writeByte(data);
mamezu	0:ffeb3e6c1367	113	}
mamezu	0:ffeb3e6c1367	114
mamezu	0:ffeb3e6c1367	115	int TextLCD::address(int column, int row) {
mamezu	0:ffeb3e6c1367	116	switch (_type) {
mamezu	0:ffeb3e6c1367	117	case LCD20x4:
mamezu	0:ffeb3e6c1367	118	switch (row) {
mamezu	0:ffeb3e6c1367	119	case 0:
mamezu	0:ffeb3e6c1367	120	return 0x80 + column;
mamezu	0:ffeb3e6c1367	121	case 1:
mamezu	0:ffeb3e6c1367	122	return 0xc0 + column;
mamezu	0:ffeb3e6c1367	123	case 2:
mamezu	0:ffeb3e6c1367	124	return 0x94 + column;
mamezu	0:ffeb3e6c1367	125	case 3:
mamezu	0:ffeb3e6c1367	126	return 0xd4 + column;
mamezu	0:ffeb3e6c1367	127	}
mamezu	0:ffeb3e6c1367	128	case LCD16x2B:
mamezu	0:ffeb3e6c1367	129	return 0x80 + (row * 40) + column;
mamezu	0:ffeb3e6c1367	130	case LCD16x2:
mamezu	0:ffeb3e6c1367	131	case LCD20x2:
mamezu	0:ffeb3e6c1367	132	default:
mamezu	0:ffeb3e6c1367	133	return 0x80 + (row * 0x40) + column;
mamezu	0:ffeb3e6c1367	134	}
mamezu	0:ffeb3e6c1367	135	}
mamezu	0:ffeb3e6c1367	136
mamezu	0:ffeb3e6c1367	137	int TextLCD::columns() {
mamezu	0:ffeb3e6c1367	138	switch (_type) {
mamezu	0:ffeb3e6c1367	139	case LCD20x4:
mamezu	0:ffeb3e6c1367	140	case LCD20x2:
mamezu	0:ffeb3e6c1367	141	return 20;
mamezu	0:ffeb3e6c1367	142	case LCD16x2:
mamezu	0:ffeb3e6c1367	143	case LCD16x2B:
mamezu	0:ffeb3e6c1367	144	default:
mamezu	0:ffeb3e6c1367	145	return 16;
mamezu	0:ffeb3e6c1367	146	}
mamezu	0:ffeb3e6c1367	147	}
mamezu	0:ffeb3e6c1367	148
mamezu	0:ffeb3e6c1367	149	int TextLCD::rows() {
mamezu	0:ffeb3e6c1367	150	switch (_type) {
mamezu	0:ffeb3e6c1367	151	case LCD20x4:
mamezu	0:ffeb3e6c1367	152	return 4;
mamezu	0:ffeb3e6c1367	153	case LCD16x2:
mamezu	0:ffeb3e6c1367	154	case LCD16x2B:
mamezu	0:ffeb3e6c1367	155	case LCD20x2:
mamezu	0:ffeb3e6c1367	156	default:
mamezu	0:ffeb3e6c1367	157	return 2;
mamezu	0:ffeb3e6c1367	158	}
mamezu	0:ffeb3e6c1367	159	}

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Type:	Library
Created:	21 Dec 2010
Imports:	340
Forks:	0
Commits:	1
Dependents:	5
Dependencies:	0
Followers:	6

TextLCD.cpp@0:ffeb3e6c1367, 2010-12-21 (annotated)

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