Bibliothèque LiquidCrystal_I2C 

Pour utiliser les afficheurs cristaux liquides connectés en I2C

initialisation : 

#include <Wire.h>  // pour communiquer en I2C
#include <LiquidCrystal_I2C.h> Pour utiliser la librairie 
LiquidCrystal_I2C lcd(0x27,16,2);  // set the LCD address to 0x27 for a 16 chars and 2 line display

Les commandes de la fonction : 

  lcd.begin(); Set the LCD display in the correct begin state, must be called before anything else is done.

  lcd.init();        // initialize the lcd 
  lcd.backlight(); // éclairage 
  lcd.clear();     //  Efface l'écran
  lcd.write(____);// écrit à l'écran
  lcd.setCursor(colonne, ligne); // positionne le curseur collone ligne, commence à 0 pour la déclaration LiquidCrystal_I2C lcd(0x27,16,2), de 0 à 15 et de 0 à 1

  lcd.home(); Next print/write operation will will start from the first position on the LCD display.

  lcd.blink(); Start blinking the cursor indicator
  lcd.noBlink(); Do not blink the cursor indicator
  lcd.noCursor(); Do not show a cursor indicator
  lcd.cursor(); Show a cursor indicator, cursor can blink on not blink. Use the methods blink() and noBlink() for changing cursor blink.
  lcd.noDisplay(); Do not show any characters on the LCD display. Backlight state will remain unchanged. Also all characters written on the display will return, when the display in enabled again.

  lcd.leftToRight(); // écrit de gauche à droite
  lcd.rightToLeft(); // écrit de droit à gauche

  lcd.display(); Show the characters on the LCD display, this is the normal behaviour. This method should only be used after noDisplay() has been used.

  lcd.scrollDisplayLeft();
	void scrollDisplayRight();
	void printLeft();
	void printRight();
	void shiftIncrement();
	void shiftDecrement();
	void noBacklight();
	void backlight();
	bool getBacklight();
	void autoscroll();
	void noAutoscroll();
	void createChar(uint8_t, uint8_t[]);
	void setCursor(uint8_t, uint8_t);
	virtual size_t write(uint8_t);
	void command(uint8_t);

Autres :

	 * Constructor
	 *
	 * @param lcd_addr	I2C slave address of the LCD display. Most likely printed on the
	 *					LCD circuit board, or look in the supplied LCD documentation.
	 * @param lcd_cols	Number of columns your LCD display has.
	 * @param lcd_rows	Number of rows your LCD display has.
	 * @param charsize	The size in dots that the display has, use LCD_5x10DOTS or LCD_5x8DOTS.
	 */
	LiquidCrystal_I2C(uint8_t lcd_addr, uint8_t lcd_cols, uint8_t lcd_rows, uint8_t charsize = LCD_5x8DOTS);