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root / arduino-1.0 / libraries / LiquidCrystal / LiquidCrystal.cpp @ 58d82c77

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#include "LiquidCrystal.h"
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#include <stdio.h>
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#include <string.h>
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#include <inttypes.h>
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#include "Arduino.h"
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// When the display powers up, it is configured as follows:
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//
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// 1. Display clear
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// 2. Function set: 
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//    DL = 1; 8-bit interface data 
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//    N = 0; 1-line display 
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//    F = 0; 5x8 dot character font 
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// 3. Display on/off control: 
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//    D = 0; Display off 
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//    C = 0; Cursor off 
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//    B = 0; Blinking off 
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// 4. Entry mode set: 
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//    I/D = 1; Increment by 1 
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//    S = 0; No shift 
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//
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// Note, however, that resetting the Arduino doesn't reset the LCD, so we
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// can't assume that its in that state when a sketch starts (and the
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// LiquidCrystal constructor is called).
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LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable,
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                             uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
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                             uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
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{
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  init(0, rs, rw, enable, d0, d1, d2, d3, d4, d5, d6, d7);
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}
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LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t enable,
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                             uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
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                             uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
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{
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  init(0, rs, 255, enable, d0, d1, d2, d3, d4, d5, d6, d7);
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}
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LiquidCrystal::LiquidCrystal(uint8_t rs, uint8_t rw, uint8_t enable,
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                             uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3)
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{
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  init(1, rs, rw, enable, d0, d1, d2, d3, 0, 0, 0, 0);
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}
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LiquidCrystal::LiquidCrystal(uint8_t rs,  uint8_t enable,
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                             uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3)
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{
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  init(1, rs, 255, enable, d0, d1, d2, d3, 0, 0, 0, 0);
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}
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void LiquidCrystal::init(uint8_t fourbitmode, uint8_t rs, uint8_t rw, uint8_t enable,
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                         uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3,
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                         uint8_t d4, uint8_t d5, uint8_t d6, uint8_t d7)
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{
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  _rs_pin = rs;
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  _rw_pin = rw;
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  _enable_pin = enable;
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  _data_pins[0] = d0;
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  _data_pins[1] = d1;
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  _data_pins[2] = d2;
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  _data_pins[3] = d3; 
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  _data_pins[4] = d4;
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  _data_pins[5] = d5;
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  _data_pins[6] = d6;
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  _data_pins[7] = d7; 
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  pinMode(_rs_pin, OUTPUT);
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  // we can save 1 pin by not using RW. Indicate by passing 255 instead of pin#
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  if (_rw_pin != 255) { 
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    pinMode(_rw_pin, OUTPUT);
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  }
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  pinMode(_enable_pin, OUTPUT);
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  if (fourbitmode)
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    _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
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  else 
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    _displayfunction = LCD_8BITMODE | LCD_1LINE | LCD_5x8DOTS;
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  begin(16, 1);  
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}
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void LiquidCrystal::begin(uint8_t cols, uint8_t lines, uint8_t dotsize) {
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  if (lines > 1) {
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    _displayfunction |= LCD_2LINE;
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  }
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  _numlines = lines;
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  _currline = 0;
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  // for some 1 line displays you can select a 10 pixel high font
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  if ((dotsize != 0) && (lines == 1)) {
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    _displayfunction |= LCD_5x10DOTS;
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  }
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  // SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
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  // according to datasheet, we need at least 40ms after power rises above 2.7V
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  // before sending commands. Arduino can turn on way befer 4.5V so we'll wait 50
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  delayMicroseconds(50000); 
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  // Now we pull both RS and R/W low to begin commands
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  digitalWrite(_rs_pin, LOW);
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  digitalWrite(_enable_pin, LOW);
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  if (_rw_pin != 255) { 
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    digitalWrite(_rw_pin, LOW);
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  }
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  //put the LCD into 4 bit or 8 bit mode
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  if (! (_displayfunction & LCD_8BITMODE)) {
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    // this is according to the hitachi HD44780 datasheet
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    // figure 24, pg 46
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    // we start in 8bit mode, try to set 4 bit mode
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    write4bits(0x03);
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    delayMicroseconds(4500); // wait min 4.1ms
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    // second try
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    write4bits(0x03);
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    delayMicroseconds(4500); // wait min 4.1ms
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    // third go!
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    write4bits(0x03); 
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    delayMicroseconds(150);
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    // finally, set to 4-bit interface
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    write4bits(0x02); 
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  } else {
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    // this is according to the hitachi HD44780 datasheet
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    // page 45 figure 23
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    // Send function set command sequence
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    command(LCD_FUNCTIONSET | _displayfunction);
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    delayMicroseconds(4500);  // wait more than 4.1ms
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    // second try
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    command(LCD_FUNCTIONSET | _displayfunction);
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    delayMicroseconds(150);
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    // third go
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    command(LCD_FUNCTIONSET | _displayfunction);
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  }
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  // finally, set # lines, font size, etc.
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  command(LCD_FUNCTIONSET | _displayfunction);  
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  // turn the display on with no cursor or blinking default
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  _displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;  
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  display();
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  // clear it off
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  clear();
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  // Initialize to default text direction (for romance languages)
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  _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
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  // set the entry mode
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  command(LCD_ENTRYMODESET | _displaymode);
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}
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/********** high level commands, for the user! */
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void LiquidCrystal::clear()
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{
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  command(LCD_CLEARDISPLAY);  // clear display, set cursor position to zero
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  delayMicroseconds(2000);  // this command takes a long time!
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}
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void LiquidCrystal::home()
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{
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  command(LCD_RETURNHOME);  // set cursor position to zero
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  delayMicroseconds(2000);  // this command takes a long time!
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}
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void LiquidCrystal::setCursor(uint8_t col, uint8_t row)
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{
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  int row_offsets[] = { 0x00, 0x40, 0x14, 0x54 };
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  if ( row >= _numlines ) {
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    row = _numlines-1;    // we count rows starting w/0
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  }
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  command(LCD_SETDDRAMADDR | (col + row_offsets[row]));
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}
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// Turn the display on/off (quickly)
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void LiquidCrystal::noDisplay() {
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  _displaycontrol &= ~LCD_DISPLAYON;
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  command(LCD_DISPLAYCONTROL | _displaycontrol);
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}
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void LiquidCrystal::display() {
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  _displaycontrol |= LCD_DISPLAYON;
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  command(LCD_DISPLAYCONTROL | _displaycontrol);
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}
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// Turns the underline cursor on/off
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void LiquidCrystal::noCursor() {
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  _displaycontrol &= ~LCD_CURSORON;
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  command(LCD_DISPLAYCONTROL | _displaycontrol);
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}
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void LiquidCrystal::cursor() {
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  _displaycontrol |= LCD_CURSORON;
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  command(LCD_DISPLAYCONTROL | _displaycontrol);
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}
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// Turn on and off the blinking cursor
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void LiquidCrystal::noBlink() {
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  _displaycontrol &= ~LCD_BLINKON;
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  command(LCD_DISPLAYCONTROL | _displaycontrol);
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}
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void LiquidCrystal::blink() {
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  _displaycontrol |= LCD_BLINKON;
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  command(LCD_DISPLAYCONTROL | _displaycontrol);
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}
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// These commands scroll the display without changing the RAM
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void LiquidCrystal::scrollDisplayLeft(void) {
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  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
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}
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void LiquidCrystal::scrollDisplayRight(void) {
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  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
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}
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// This is for text that flows Left to Right
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void LiquidCrystal::leftToRight(void) {
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  _displaymode |= LCD_ENTRYLEFT;
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  command(LCD_ENTRYMODESET | _displaymode);
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}
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// This is for text that flows Right to Left
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void LiquidCrystal::rightToLeft(void) {
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  _displaymode &= ~LCD_ENTRYLEFT;
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  command(LCD_ENTRYMODESET | _displaymode);
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}
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// This will 'right justify' text from the cursor
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void LiquidCrystal::autoscroll(void) {
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  _displaymode |= LCD_ENTRYSHIFTINCREMENT;
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  command(LCD_ENTRYMODESET | _displaymode);
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}
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// This will 'left justify' text from the cursor
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void LiquidCrystal::noAutoscroll(void) {
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  _displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
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  command(LCD_ENTRYMODESET | _displaymode);
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}
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// Allows us to fill the first 8 CGRAM locations
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// with custom characters
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void LiquidCrystal::createChar(uint8_t location, uint8_t charmap[]) {
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  location &= 0x7; // we only have 8 locations 0-7
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  command(LCD_SETCGRAMADDR | (location << 3));
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  for (int i=0; i<8; i++) {
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    write(charmap[i]);
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  }
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}
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/*********** mid level commands, for sending data/cmds */
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inline void LiquidCrystal::command(uint8_t value) {
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  send(value, LOW);
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}
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inline size_t LiquidCrystal::write(uint8_t value) {
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  send(value, HIGH);
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  return 1; // assume sucess
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}
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/************ low level data pushing commands **********/
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// write either command or data, with automatic 4/8-bit selection
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void LiquidCrystal::send(uint8_t value, uint8_t mode) {
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  digitalWrite(_rs_pin, mode);
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  // if there is a RW pin indicated, set it low to Write
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  if (_rw_pin != 255) { 
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    digitalWrite(_rw_pin, LOW);
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  }
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  if (_displayfunction & LCD_8BITMODE) {
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    write8bits(value); 
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  } else {
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    write4bits(value>>4);
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    write4bits(value);
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  }
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}
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void LiquidCrystal::pulseEnable(void) {
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  digitalWrite(_enable_pin, LOW);
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  delayMicroseconds(1);    
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  digitalWrite(_enable_pin, HIGH);
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  delayMicroseconds(1);    // enable pulse must be >450ns
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  digitalWrite(_enable_pin, LOW);
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  delayMicroseconds(100);   // commands need > 37us to settle
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}
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void LiquidCrystal::write4bits(uint8_t value) {
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  for (int i = 0; i < 4; i++) {
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    pinMode(_data_pins[i], OUTPUT);
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    digitalWrite(_data_pins[i], (value >> i) & 0x01);
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  }
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  pulseEnable();
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}
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void LiquidCrystal::write8bits(uint8_t value) {
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  for (int i = 0; i < 8; i++) {
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    pinMode(_data_pins[i], OUTPUT);
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    digitalWrite(_data_pins[i], (value >> i) & 0x01);
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  }
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  pulseEnable();
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}