source: arduino-1-6-7/trunk/fuentes/arduino-ide-amd64/libraries/LiquidCrystal/src/LiquidCrystal.cpp @ 46

Last change on this file since 46 was 46, checked in by jrpelegrina, 4 years ago

First release to Xenial

File size: 8.9 KB
Line 
1#include "LiquidCrystal.h"
2
3#include <stdio.h>
4#include <string.h>
5#include <inttypes.h>
6#include "Arduino.h"
7
8// When the display powers up, it is configured as follows:
9//
10// 1. Display clear
11// 2. Function set:
12//    DL = 1; 8-bit interface data
13//    N = 0; 1-line display
14//    F = 0; 5x8 dot character font
15// 3. Display on/off control:
16//    D = 0; Display off
17//    C = 0; Cursor off
18//    B = 0; Blinking off
19// 4. Entry mode set:
20//    I/D = 1; Increment by 1
21//    S = 0; No shift
22//
23// Note, however, that resetting the Arduino doesn't reset the LCD, so we
24// can't assume that its in that state when a sketch starts (and the
25// LiquidCrystal constructor is called).
26
27LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable,
28                             uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
29                             uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
30{
31  init(0, rs, rw, enable, d0, d1, d2, d3, d4, d5, d6, d7);
32}
33
34LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t enable,
35                             uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
36                             uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
37{
38  init(0, rs, 255, enable, d0, d1, d2, d3, d4, d5, d6, d7);
39}
40
41LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable,
42                             uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3)
43{
44  init(1, rs, rw, enable, d0, d1, d2, d3, 0, 0, 0, 0);
45}
46
47LiquidCrystal::LiquidCrystal(uint8_t rs,  uint8_t enable,
48                             uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3)
49{
50  init(1, rs, 255, enable, d0, d1, d2, d3, 0, 0, 0, 0);
51}
52
53void LiquidCrystal::init(uint8_t fourbitmode, uint8_t rs, uint8_t rw, uint8_t enable,
54                         uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
55                         uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
56{
57  _rs_pin = rs;
58  _rw_pin = rw;
59  _enable_pin = enable;
60 
61  _data_pins[0] = d0;
62  _data_pins[1] = d1;
63  _data_pins[2] = d2;
64  _data_pins[3] = d3; 
65  _data_pins[4] = d4;
66  _data_pins[5] = d5;
67  _data_pins[6] = d6;
68  _data_pins[7] = d7; 
69
70  if (fourbitmode)
71    _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
72  else 
73    _displayfunction = LCD_8BITMODE | LCD_1LINE | LCD_5x8DOTS;
74 
75  begin(16, 1); 
76}
77
78void LiquidCrystal::begin(uint8_t cols, uint8_t lines, uint8_t dotsize) {
79  if (lines > 1) {
80    _displayfunction |= LCD_2LINE;
81  }
82  _numlines = lines;
83
84  setRowOffsets(0x00, 0x40, 0x00 + cols, 0x40 + cols); 
85
86  // for some 1 line displays you can select a 10 pixel high font
87  if ((dotsize != LCD_5x8DOTS) && (lines == 1)) {
88    _displayfunction |= LCD_5x10DOTS;
89  }
90
91  pinMode(_rs_pin, OUTPUT);
92  // we can save 1 pin by not using RW. Indicate by passing 255 instead of pin#
93  if (_rw_pin != 255) { 
94    pinMode(_rw_pin, OUTPUT);
95  }
96  pinMode(_enable_pin, OUTPUT);
97 
98  // Do these once, instead of every time a character is drawn for speed reasons.
99  for (int i=0; i<((_displayfunction & LCD_8BITMODE) ? 8 : 4); ++i)
100  {
101    pinMode(_data_pins[i], OUTPUT);
102   } 
103
104  // SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
105  // according to datasheet, we need at least 40ms after power rises above 2.7V
106  // before sending commands. Arduino can turn on way before 4.5V so we'll wait 50
107  delayMicroseconds(50000); 
108  // Now we pull both RS and R/W low to begin commands
109  digitalWrite(_rs_pin, LOW);
110  digitalWrite(_enable_pin, LOW);
111  if (_rw_pin != 255) { 
112    digitalWrite(_rw_pin, LOW);
113  }
114 
115  //put the LCD into 4 bit or 8 bit mode
116  if (! (_displayfunction & LCD_8BITMODE)) {
117    // this is according to the hitachi HD44780 datasheet
118    // figure 24, pg 46
119
120    // we start in 8bit mode, try to set 4 bit mode
121    write4bits(0x03);
122    delayMicroseconds(4500); // wait min 4.1ms
123
124    // second try
125    write4bits(0x03);
126    delayMicroseconds(4500); // wait min 4.1ms
127   
128    // third go!
129    write4bits(0x03); 
130    delayMicroseconds(150);
131
132    // finally, set to 4-bit interface
133    write4bits(0x02); 
134  } else {
135    // this is according to the hitachi HD44780 datasheet
136    // page 45 figure 23
137
138    // Send function set command sequence
139    command(LCD_FUNCTIONSET | _displayfunction);
140    delayMicroseconds(4500);  // wait more than 4.1ms
141
142    // second try
143    command(LCD_FUNCTIONSET | _displayfunction);
144    delayMicroseconds(150);
145
146    // third go
147    command(LCD_FUNCTIONSET | _displayfunction);
148  }
149
150  // finally, set # lines, font size, etc.
151  command(LCD_FUNCTIONSET | _displayfunction); 
152
153  // turn the display on with no cursor or blinking default
154  _displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF; 
155  display();
156
157  // clear it off
158  clear();
159
160  // Initialize to default text direction (for romance languages)
161  _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
162  // set the entry mode
163  command(LCD_ENTRYMODESET | _displaymode);
164
165}
166
167void LiquidCrystal::setRowOffsets(int row0, int row1, int row2, int row3)
168{
169  _row_offsets[0] = row0;
170  _row_offsets[1] = row1;
171  _row_offsets[2] = row2;
172  _row_offsets[3] = row3;
173}
174
175/********** high level commands, for the user! */
176void LiquidCrystal::clear()
177{
178  command(LCD_CLEARDISPLAY);  // clear display, set cursor position to zero
179  delayMicroseconds(2000);  // this command takes a long time!
180}
181
182void LiquidCrystal::home()
183{
184  command(LCD_RETURNHOME);  // set cursor position to zero
185  delayMicroseconds(2000);  // this command takes a long time!
186}
187
188void LiquidCrystal::setCursor(uint8_t col, uint8_t row)
189{
190  const size_t max_lines = sizeof(_row_offsets) / sizeof(*_row_offsets);
191  if ( row >= max_lines ) {
192    row = max_lines - 1;    // we count rows starting w/0
193  }
194  if ( row >= _numlines ) {
195    row = _numlines - 1;    // we count rows starting w/0
196  }
197 
198  command(LCD_SETDDRAMADDR | (col + _row_offsets[row]));
199}
200
201// Turn the display on/off (quickly)
202void LiquidCrystal::noDisplay() {
203  _displaycontrol &= ~LCD_DISPLAYON;
204  command(LCD_DISPLAYCONTROL | _displaycontrol);
205}
206void LiquidCrystal::display() {
207  _displaycontrol |= LCD_DISPLAYON;
208  command(LCD_DISPLAYCONTROL | _displaycontrol);
209}
210
211// Turns the underline cursor on/off
212void LiquidCrystal::noCursor() {
213  _displaycontrol &= ~LCD_CURSORON;
214  command(LCD_DISPLAYCONTROL | _displaycontrol);
215}
216void LiquidCrystal::cursor() {
217  _displaycontrol |= LCD_CURSORON;
218  command(LCD_DISPLAYCONTROL | _displaycontrol);
219}
220
221// Turn on and off the blinking cursor
222void LiquidCrystal::noBlink() {
223  _displaycontrol &= ~LCD_BLINKON;
224  command(LCD_DISPLAYCONTROL | _displaycontrol);
225}
226void LiquidCrystal::blink() {
227  _displaycontrol |= LCD_BLINKON;
228  command(LCD_DISPLAYCONTROL | _displaycontrol);
229}
230
231// These commands scroll the display without changing the RAM
232void LiquidCrystal::scrollDisplayLeft(void) {
233  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
234}
235void LiquidCrystal::scrollDisplayRight(void) {
236  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
237}
238
239// This is for text that flows Left to Right
240void LiquidCrystal::leftToRight(void) {
241  _displaymode |= LCD_ENTRYLEFT;
242  command(LCD_ENTRYMODESET | _displaymode);
243}
244
245// This is for text that flows Right to Left
246void LiquidCrystal::rightToLeft(void) {
247  _displaymode &= ~LCD_ENTRYLEFT;
248  command(LCD_ENTRYMODESET | _displaymode);
249}
250
251// This will 'right justify' text from the cursor
252void LiquidCrystal::autoscroll(void) {
253  _displaymode |= LCD_ENTRYSHIFTINCREMENT;
254  command(LCD_ENTRYMODESET | _displaymode);
255}
256
257// This will 'left justify' text from the cursor
258void LiquidCrystal::noAutoscroll(void) {
259  _displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
260  command(LCD_ENTRYMODESET | _displaymode);
261}
262
263// Allows us to fill the first 8 CGRAM locations
264// with custom characters
265void LiquidCrystal::createChar(uint8_t location, uint8_t charmap[]) {
266  location &= 0x7; // we only have 8 locations 0-7
267  command(LCD_SETCGRAMADDR | (location << 3));
268  for (int i=0; i<8; i++) {
269    write(charmap[i]);
270  }
271}
272
273/*********** mid level commands, for sending data/cmds */
274
275inline void LiquidCrystal::command(uint8_t value) {
276  send(value, LOW);
277}
278
279inline size_t LiquidCrystal::write(uint8_t value) {
280  send(value, HIGH);
281  return 1; // assume sucess
282}
283
284/************ low level data pushing commands **********/
285
286// write either command or data, with automatic 4/8-bit selection
287void LiquidCrystal::send(uint8_t value, uint8_t mode) {
288  digitalWrite(_rs_pin, mode);
289
290  // if there is a RW pin indicated, set it low to Write
291  if (_rw_pin != 255) { 
292    digitalWrite(_rw_pin, LOW);
293  }
294 
295  if (_displayfunction & LCD_8BITMODE) {
296    write8bits(value); 
297  } else {
298    write4bits(value>>4);
299    write4bits(value);
300  }
301}
302
303void LiquidCrystal::pulseEnable(void) {
304  digitalWrite(_enable_pin, LOW);
305  delayMicroseconds(1);   
306  digitalWrite(_enable_pin, HIGH);
307  delayMicroseconds(1);    // enable pulse must be >450ns
308  digitalWrite(_enable_pin, LOW);
309  delayMicroseconds(100);   // commands need > 37us to settle
310}
311
312void LiquidCrystal::write4bits(uint8_t value) {
313  for (int i = 0; i < 4; i++) {
314    digitalWrite(_data_pins[i], (value >> i) & 0x01);
315  }
316
317  pulseEnable();
318}
319
320void LiquidCrystal::write8bits(uint8_t value) {
321  for (int i = 0; i < 8; i++) {
322    digitalWrite(_data_pins[i], (value >> i) & 0x01);
323  }
324 
325  pulseEnable();
326}
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