WattBob_TextLCD - Set of routines to access 16*32character LCD disp…

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Set of routines to access 16*32character LCD display on WattBob I board.

Dependents: Assignment_2_herpe Final_V1 ass2 ass2 ... more

WattBob_TextLCD.cpp@9:3b26cd028e85, 2011-12-11 (annotated)

Committer:: jimherd
Date:: Sun Dec 11 00:14:10 2011 +0000
Revision:: 9:3b26cd028e85
Parent:: 8:5a1c4254e4a6

Who changed what in which revision?

User	Revision	Line number	New contents of line
jimherd	0:e5b7c70254ac	1	/* draft mbed TextLCD
jimherd	0:e5b7c70254ac	2	* (c) 2007/8, sford
jimherd	0:e5b7c70254ac	3	* Modified jherd
jimherd	0:e5b7c70254ac	4	*/
jimherd	0:e5b7c70254ac	5
jimherd	0:e5b7c70254ac	6	#include "WattBob_TextLCD.h"
jimherd	0:e5b7c70254ac	7	#include "MCP23017.h"
jimherd	0:e5b7c70254ac	8
jimherd	0:e5b7c70254ac	9	#include "mbed.h"
jimherd	0:e5b7c70254ac	10
jimherd	0:e5b7c70254ac	11	/*
jimherd	0:e5b7c70254ac	12	* Initialisation
jimherd	0:e5b7c70254ac	13	* ==============
jimherd	0:e5b7c70254ac	14	*
jimherd	0:e5b7c70254ac	15	* After attaching the supply voltage/after a reset, the display needs to be brought in to a defined state
jimherd	0:e5b7c70254ac	16	*
jimherd	0:e5b7c70254ac	17	* - wait approximately 15 ms so the display is ready to execute commands
jimherd	0:e5b7c70254ac	18	* - Execute the command 0x30 ("Display Settings") three times (wait 1,64ms after each command, the busy flag cannot be queried now).
jimherd	0:e5b7c70254ac	19	* - 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.
jimherd	0:e5b7c70254ac	20	* - If you want to use the 4 bit mode, now you can execute the command to switch over to this mode now.
jimherd	0:e5b7c70254ac	21	* - Execute the "clear display" command
jimherd	0:e5b7c70254ac	22	*
jimherd	0:e5b7c70254ac	23	* Timing
jimherd	0:e5b7c70254ac	24	* ======
jimherd	0:e5b7c70254ac	25	*
jimherd	0:e5b7c70254ac	26	* Nearly all commands transmitted to the display need 40us for execution.
jimherd	0:e5b7c70254ac	27	* Exceptions are the commands "Clear Display and Reset" and "Set Cursor to Start Position"
jimherd	0:e5b7c70254ac	28	* These commands need 1.64ms for execution. These timings are valid for all displays working with an
jimherd	0:e5b7c70254ac	29	* internal clock of 250kHz. But I do not know any displays that use other frequencies. Any time you
jimherd	0:e5b7c70254ac	30	* can use the busy flag to test if the display is ready to accept the next command.
jimherd	0:e5b7c70254ac	31	*
jimherd	0:e5b7c70254ac	32	* _e is kept high apart from calling clock
jimherd	0:e5b7c70254ac	33	* _rw is kept 0 (write) apart from actions that uses it differently
jimherd	0:e5b7c70254ac	34	* _rs is set by the data/command writes
jimherd	0:e5b7c70254ac	35	*
jimherd	0:e5b7c70254ac	36	* RS = 7
jimherd	0:e5b7c70254ac	37	* RW = 6
jimherd	0:e5b7c70254ac	38	* E = 5
jimherd	0:e5b7c70254ac	39	* Back light = 4
jimherd	0:e5b7c70254ac	40	* D4 = 0
jimherd	0:e5b7c70254ac	41	* D5 = 1
jimherd	0:e5b7c70254ac	42	* D6 = 2
jimherd	0:e5b7c70254ac	43	* D7 = 3
jimherd	0:e5b7c70254ac	44	*/
jimherd	0:e5b7c70254ac	45
jimherd	0:e5b7c70254ac	46	WattBob_TextLCD::WattBob_TextLCD(MCP23017 *port) {
jimherd	0:e5b7c70254ac	47	//
jimherd	0:e5b7c70254ac	48	// Initialise pointer to MCP23017 object
jimherd	0:e5b7c70254ac	49	//
jimherd	0:e5b7c70254ac	50	par_port = port;
jimherd	0:e5b7c70254ac	51	par_port->config(0x0F00, 0x0F00, 0x0F00);
jimherd	0:e5b7c70254ac	52
jimherd	0:e5b7c70254ac	53	_rows = 2;
jimherd	0:e5b7c70254ac	54	_columns = 16;
jimherd	0:e5b7c70254ac	55
jimherd	9:3b26cd028e85	56	//
jimherd	9:3b26cd028e85	57	// Time to allow unit to initialise
jimherd	9:3b26cd028e85	58	//
jimherd	9:3b26cd028e85	59	wait(DISPLAY_INIT_DELAY_SECS);
jimherd	9:3b26cd028e85	60
jimherd	0:e5b7c70254ac	61	_rw(0);
jimherd	0:e5b7c70254ac	62	_e(0);
jimherd	0:e5b7c70254ac	63	_rs(0); // command mode
jimherd	0:e5b7c70254ac	64
jimherd	8:5a1c4254e4a6	65	//
jimherd	8:5a1c4254e4a6	66	// interface defaults to an 8-bit interface. However, we need to ensure that we
jimherd	8:5a1c4254e4a6	67	// are in 8-bit mode
jimherd	8:5a1c4254e4a6	68	//
jimherd	0:e5b7c70254ac	69	for(int i=0; i<3; i++) {
jimherd	8:5a1c4254e4a6	70	writeNibble(CMD4_SET_8_BIT_INTERFACE);
jimherd	0:e5b7c70254ac	71	wait(0.00164); // this command takes 1.64ms, so wait for it
jimherd	0:e5b7c70254ac	72	}
jimherd	8:5a1c4254e4a6	73
jimherd	9:3b26cd028e85	74	writeNibble(CMD4_SET_4_BIT_INTERFACE); // now force into 4-bit mode
jimherd	9:3b26cd028e85	75
jimherd	9:3b26cd028e85	76	// writeCommand(CMD_NULL);
jimherd	9:3b26cd028e85	77	// writeCommand(CMD_NULL);
jimherd	9:3b26cd028e85	78	// writeCommand(CMD_NULL);
jimherd	9:3b26cd028e85	79	// writeCommand(CMD_NULL);
jimherd	9:3b26cd028e85	80	// writeCommand(CMD_NULL);
jimherd	9:3b26cd028e85	81
jimherd	8:5a1c4254e4a6	82	writeCommand(CMD_FUNCTION_SET \| INTERFACE_4_BIT \| TWO_LINE_DISPLAY \| FONT_5x8 \| ENGL_JAPAN_FONT_SET); // 0x28
jimherd	8:5a1c4254e4a6	83	writeCommand(CMD_DISPLAY_CONTROL \| DISPLAY_ON \| CURSOR_OFF \| CURSOR_CHAR_BLINK_OFF); // 0xC0
jimherd	9:3b26cd028e85	84	cls();
jimherd	9:3b26cd028e85	85	writeCommand(CMD_RETURN_HOME);
jimherd	8:5a1c4254e4a6	86	writeCommand(CMD_ENTRY_MODE \| CURSOR_STEP_RIGHT \| DISPLAY_SHIFT_OFF ); // 0x06
jimherd	0:e5b7c70254ac	87	}
jimherd	0:e5b7c70254ac	88
jimherd	0:e5b7c70254ac	89	int WattBob_TextLCD::_putc(int value) {
jimherd	0:e5b7c70254ac	90	if(value == '\n') {
jimherd	0:e5b7c70254ac	91	newline();
jimherd	0:e5b7c70254ac	92	} else {
jimherd	0:e5b7c70254ac	93	writeData(value);
jimherd	0:e5b7c70254ac	94	}
jimherd	0:e5b7c70254ac	95	return value;
jimherd	0:e5b7c70254ac	96	}
jimherd	0:e5b7c70254ac	97
jimherd	0:e5b7c70254ac	98	int WattBob_TextLCD::_getc() {
jimherd	0:e5b7c70254ac	99	return 0;
jimherd	0:e5b7c70254ac	100	}
jimherd	0:e5b7c70254ac	101
jimherd	0:e5b7c70254ac	102	void WattBob_TextLCD::newline() {
jimherd	0:e5b7c70254ac	103	_column = 0;
jimherd	0:e5b7c70254ac	104	_row++;
jimherd	0:e5b7c70254ac	105	if(_row >= _rows) {
jimherd	0:e5b7c70254ac	106	_row = 0;
jimherd	0:e5b7c70254ac	107	}
jimherd	0:e5b7c70254ac	108	locate(_column, _row);
jimherd	0:e5b7c70254ac	109	}
jimherd	0:e5b7c70254ac	110
jimherd	0:e5b7c70254ac	111	void WattBob_TextLCD::locate(int row, int column) {
jimherd	0:e5b7c70254ac	112	if(column < 0 \|\| column >= _columns \|\| row < 0 \|\| row >= _rows) {
jimherd	0:e5b7c70254ac	113	// error("locate(%d,%d) out of range on %dx%d display", column, row, _columns, _rows);
jimherd	0:e5b7c70254ac	114	return;
jimherd	0:e5b7c70254ac	115	}
jimherd	0:e5b7c70254ac	116
jimherd	0:e5b7c70254ac	117	_row = row;
jimherd	0:e5b7c70254ac	118	_column = column;
jimherd	7:020722c18a8b	119	int address = 0x80 + (_row * 0x40) + _column; // memory starts at 0x80, and internally it is 40 chars per row (only first 16 used)
jimherd	0:e5b7c70254ac	120	writeCommand(address);
jimherd	0:e5b7c70254ac	121	}
jimherd	0:e5b7c70254ac	122
jimherd	0:e5b7c70254ac	123	void WattBob_TextLCD::cls() {
jimherd	8:5a1c4254e4a6	124	writeCommand(CMD_CLEAR_DISPLAY); // 0x01
jimherd	9:3b26cd028e85	125	wait(DISPLAY_CLEAR_DELAY); //
jimherd	8:5a1c4254e4a6	126	locate(0, 0);
jimherd	0:e5b7c70254ac	127	}
jimherd	0:e5b7c70254ac	128
jimherd	0:e5b7c70254ac	129	void WattBob_TextLCD::reset() {
jimherd	0:e5b7c70254ac	130	cls();
jimherd	0:e5b7c70254ac	131	}
jimherd	0:e5b7c70254ac	132
jimherd	0:e5b7c70254ac	133	void WattBob_TextLCD::clock() {
jimherd	0:e5b7c70254ac	134	wait(0.000040f);
jimherd	0:e5b7c70254ac	135	_e(1);
jimherd	0:e5b7c70254ac	136	wait(0.000040f); // most instructions take 40us
jimherd	0:e5b7c70254ac	137	_e(0);
jimherd	0:e5b7c70254ac	138	}
jimherd	0:e5b7c70254ac	139
jimherd	0:e5b7c70254ac	140	void WattBob_TextLCD::writeNibble(int value) {
jimherd	0:e5b7c70254ac	141	_d(value);
jimherd	0:e5b7c70254ac	142	clock();
jimherd	0:e5b7c70254ac	143	}
jimherd	0:e5b7c70254ac	144
jimherd	0:e5b7c70254ac	145	void WattBob_TextLCD::writeByte(int value) {
jimherd	0:e5b7c70254ac	146	writeNibble((value >> 4) & 0x000F);
jimherd	0:e5b7c70254ac	147	writeNibble((value >> 0) & 0x000F);
jimherd	0:e5b7c70254ac	148	}
jimherd	0:e5b7c70254ac	149
jimherd	0:e5b7c70254ac	150	void WattBob_TextLCD::writeCommand(int command) {
jimherd	0:e5b7c70254ac	151	_rs(0);
jimherd	0:e5b7c70254ac	152	writeByte(command);
jimherd	0:e5b7c70254ac	153	}
jimherd	0:e5b7c70254ac	154
jimherd	0:e5b7c70254ac	155	void WattBob_TextLCD::writeData(int data) {
jimherd	0:e5b7c70254ac	156	_rs(1);
jimherd	0:e5b7c70254ac	157	writeByte(data);
jimherd	0:e5b7c70254ac	158	_column++;
jimherd	0:e5b7c70254ac	159	if(_column >= _columns) {
jimherd	0:e5b7c70254ac	160	newline();
jimherd	0:e5b7c70254ac	161	}
jimherd	0:e5b7c70254ac	162	}
jimherd	0:e5b7c70254ac	163
jimherd	0:e5b7c70254ac	164	void WattBob_TextLCD::_rs(int data) {
jimherd	0:e5b7c70254ac	165	par_port->write_bit(data, RS_BIT);
jimherd	0:e5b7c70254ac	166	}
jimherd	0:e5b7c70254ac	167
jimherd	0:e5b7c70254ac	168	void WattBob_TextLCD::_rw(int data) {
jimherd	0:e5b7c70254ac	169	par_port->write_bit(data, RW_BIT);
jimherd	0:e5b7c70254ac	170	}
jimherd	0:e5b7c70254ac	171
jimherd	0:e5b7c70254ac	172	void WattBob_TextLCD::_e(int data) {
jimherd	0:e5b7c70254ac	173	par_port->write_bit(data, E_BIT);
jimherd	0:e5b7c70254ac	174	}
jimherd	0:e5b7c70254ac	175
jimherd	0:e5b7c70254ac	176	void WattBob_TextLCD::_d(int data) {
jimherd	0:e5b7c70254ac	177	par_port->write_mask((unsigned short)data, (unsigned short)0x000F);
jimherd	0:e5b7c70254ac	178	}

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Type:	Library
Created:	28 Nov 2010
Imports:	1891
Forks:	0
Commits:	10
Dependents:	26
Dependencies:	0
Followers:	50

WattBob_TextLCD.cpp@9:3b26cd028e85, 2011-12-11 (annotated)

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