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LiquidCrystal_I2C.h
executable file
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LiquidCrystal_I2C.h
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// ---------------------------------------------------------------------------
// Created by Francisco Malpartida on 20/08/11.
// Copyright 2011 - Under creative commons license 3.0:
// Attribution-ShareAlike CC BY-SA
//
// This software is furnished "as is", without technical support, and with no
// warranty, express or implied, as to its usefulness for any purpose.
//
// Thread Safe: No
// Extendable: Yes
//
// @file LiquidCrystal_I2C.h
// This file implements a basic liquid crystal library that comes as standard
// in the Arduino SDK but using an I2C IO extension board.
//
// @brief
// This is a basic implementation of the LiquidCrystal library of the
// Arduino SDK. The original library has been reworked in such a way that
// this class implements the all methods to command an LCD based
// on the Hitachi HD44780 and compatible chipsets using I2C extension
// backpacks such as the I2CLCDextraIO with the PCF8574* I2C IO Expander ASIC.
//
// The functionality provided by this class and its base class is identical
// to the original functionality of the Arduino LiquidCrystal library.
//
//
// This library is only compatible with Arduino's SDK version 1.0
//
//
// @author F. Malpartida - fmalpartida@gmail.com
// ---------------------------------------------------------------------------
#ifndef LiquidCrystal_I2C_h
#define LiquidCrystal_I2C_h
#include <inttypes.h>
#include <Print.h>
#include <I2CIO.h>
#include <LCD.h>
// flags for backlight control
#define LCD_BACKLIGHT 0x00
#define LCD_NOBACKLIGHT 0x80
/*!
@warning These definitions will have to be changed should the IOExpander be
connected differently to this default.
*/
/*!
@defined
@abstract Enable bit of the LCD
@discussion Defines the IO of the expander connected to the LCD Enable
*/
#define EN B01000000 // Enable bit
/*!
@defined
@abstract Read/Write bit of the LCD
@discussion Defines the IO of the expander connected to the LCD Rw pin
*/
#define RW B00100000 // Read/Write bit
/*!
@defined
@abstract Register bit of the LCD
@discussion Defines the IO of the expander connected to the LCD Register select pin
*/
#define RS B00010000 // Register select bit
class LiquidCrystal_I2C : public LCD
{
public:
/*!
@method
@abstract Class constructor.
@discussion Initializes class variables and defines the I2C address of the
LCD. The constructor does not initialize the LCD.
@param lcd_Addr[in] I2C address of the IO expansion module. For I2CLCDextraIO,
the address can be configured using the on board jumpers.
*/
LiquidCrystal_I2C (uint8_t lcd_Addr);
/*!
@method
@abstract Class constructor.
@discussion Initializes class variables and defines the I2C address of the
LCD. The constructor does not initialize the LCD.
@param lcd_Addr[in] I2C address of the IO expansion module. For I2CLCDextraIO,
the address can be configured using the on board jumpers.
@param En[in] LCD En (Enable) pin connected to the IO extender module
@param Rw[in] LCD Rw (Read/write) pin connected to the IO extender module
@param Rs[in] LCD Rs (Reset) pin connected to the IO extender module
*/
LiquidCrystal_I2C( uint8_t lcd_Addr, uint8_t En, uint8_t Rw, uint8_t Rs);
/*!
@method
@abstract Class constructor.
@discussion Initializes class variables and defines the I2C address of the
LCD. The constructor does not initialize the LCD.
@param lcd_Addr[in] I2C address of the IO expansion module. For I2CLCDextraIO,
the address can be configured using the on board jumpers.
@param En[in] LCD En (Enable) pin connected to the IO extender module
@param Rw[in] LCD Rw (Read/write) pin connected to the IO extender module
@param Rs[in] LCD Rs (Reset) pin connected to the IO extender module
@param d0[in] LCD data 0 pin map on IO extender module
@param d1[in] LCD data 1 pin map on IO extender module
@param d2[in] LCD data 2 pin map on IO extender module
@param d3[in] LCD data 3 pin map on IO extender module
*/
LiquidCrystal_I2C( uint8_t lcd_Addr, uint8_t En, uint8_t Rw, uint8_t Rs,
uint8_t d0, uint8_t d1, uint8_t d2, uint8_t d3 );
/*!
@function
@abstract LCD initialization.
@discussion Initializes the LCD to a given size (col, row). This methods
initializes the LCD, therefore, it MUST be called prior to using any other
method from this class or parent class.
@param cols[in] the number of columns that the display has
@param rows[in] the number of rows that the display has
@param charsize[in] size of the characters of the LCD: LCD_5x8DOTS or
LCD_5x10DOTS.
*/
virtual void begin(uint8_t cols, uint8_t rows, uint8_t charsize = LCD_5x8DOTS);
/*!
@function
@abstract Send a particular value to the LCD.
@discussion Sends a particular value to the LCD for writing to the LCD or
as an LCD command.
Users should never call this method.
@param value[in] Value to send to the LCD.
@param mode[in] DATA - write to the LCD CGRAM, COMMAND - write a
command to the LCD.
*/
virtual void send(uint8_t value, uint8_t mode);
/*!
@function
@abstract Switch-off the LCD backlight.
@discussion Switch-off the LCD backlight, this method is not supported by
the I2CLCDextraIO, it needs an extra IO pin to drive the LCD backlight
@param none
*/
void noBacklight();
/*!
@function
@abstract Switch-on the LCD backlight.
@discussion Switch-on the LCD backlight, this method is not supported by
the I2CLCDextraIO, it needs an extra IO pin to drive the LCD backlight
@param none
*/
void backlight();
private:
/*!
@method
@abstract Initializes the LCD class
@discussion Initializes the LCD class and IO expansion module.
*/
int init();
/*!
@method
@abstract Writes an 4 bit value to the LCD.
@discussion Writes 4 bits (the least significant) to the LCD control data lines.
@param value[in] Value to write to the LCD
@param more[in] Value to distinguish between command and data.
COMMAND == command, DATA == data.
*/
void write4bits(uint8_t value, uint8_t mode);
/*!
@method
@abstract Pulse the LCD enable line (En).
@discussion Sends a pulse of 1 uS to the Enable pin to execute an command
or write operation.
*/
void pulseEnable(uint8_t);
/*!
@method
@abstract Writes to the expansion module.
@discussion Writes a byte to the IO expansion module. This will be applied
to all its outputs.
*/
void expanderWrite(uint8_t);
uint8_t _Addr; // I2C Address of the IO expander
uint8_t _backlightval; // Backlight shadow value
I2CIO _i2cio; // I2CIO PCF8574* expansion module driver I2CLCDextraIO
uint8_t _En; // LCD expander word for enable pin
uint8_t _Rw; // LCD expander word for R/W pin
uint8_t _Rs; // LCD expander word for Register Select pin
uint8_t _data_pins[4]; // LCD data lines
};
#endif