root/twiLCD/twiLCD.h

#ifndef twiLCD_H
#define twiLCD_H
    #include "../global.h"
    
    #include "../configs/LCD/lcd.h"
    #include "../configs/twiLCD/twiLCD.h"
    
#ifndef PCF8574_A0
    #define PCF8574_A0          0
#endif
#ifndef PCF8574_A1
    #define PCF8574_A1          0
#endif
#ifndef PCF8574_A2
    #define PCF8574_A2          0
#endif
    
    #define PCF8574_BASE_ADDR   B00100000
    #define PCF8574_WADDR       PCF8574_BASE_ADDR | (PCF8574_A0 * B00000001) | (PCF8574_A1 * B00000010) | (PCF8574_A2 * B00000100)
    #define PCF8574_RADDR       PCF8574_WADDR | 0x01
    
    #define TWI_LCD_RS          0   /* RS pin */
    #define TWI_LCD_RW          1   /* RW pin */
    #define TWI_LCD_ENABLE      2   /* Enable pin */
#ifdef TWI_LCD_CTRL
#ifdef TWI_LCD_BL_PWM
    #define TWI_LCD_BACKLIGHT   9   /* This is an Arduino pin number! */
#else
    #define TWI_LCD_BACKLIGHT   3   /* Backlight pin */
#endif
#endif
    
    #define TWI_LCD_CONTROL     B00000111   /* Mask for the 3 control bits (E, RS, RW) */
    #define TWI_LCD_DATA        B11110000   /* Mask for the 4 bit word */
    #define TWI_LCD_DATAH       B11110000
    #define TWI_LCD_DATAL       B00001111
    #define TWI_LCD_BUSY        B00001000
    
#ifndef printString
    #define printString(str)    printString_P(PSTR(str))
#endif
    
#ifdef LCD_USE_CLRSCREEN_CALLBACK
    volatile static voidFuncPtr twiLCDcallbackFunc[1];
#endif
    
    class twiLCD {
        public:
            /**
             * Constructor: initializes this class
            **/
            twiLCD();
            
            /**
             * LCD Initilization method
            **/
            void    Init();
            
            /**
             * writeData: write a byte of data to the LCD
             * @param: value: the byte to write
            **/
            void    writeData(uint8_t);
            
            /**
             * clearScreen: clears the LCD and resets the cursor position to 0,0
            **/
            void    clearScreen(void);
            
            /**
             * printString_P: prints a program string to the LCD
             *  To call this function, use the LCD.printString() macro!
            **/
            void    printString_P(const char *);
            
        #ifdef LCD_USE_CLRSCREEN_CALLBACK
            void    clrsSetCallback(void (*)(void));
        #endif
    /**
     * These function are only available on the mega168 for space reasons
    **/
    #if defined(__AVR_ATmega168__) && !defined(TWI_LCD_SMALL)
        
        /**
         * Methods for dealing with LCD timeout
         * Returns true if the time is expired
        **/
        #ifdef TWI_LCD_USE_TIMEOUT
            boolean checkTimeout(void);
        #endif
        
        /**
         * Backlight control functions
         * Optionally enabled above
        **/
        #ifdef TWI_LCD_CTRL
            /**
             * backlightOn: Turn on the backlight at full brightness
            **/
            void    backlightOn(void);
            
            /**
             * backlightOff: turn off the LCD backlight
            **/
            void    backlightOff(void);
            
            // PWM Backlight Control
            #if defined(TWI_LCD_BL_PWM) || defined(TWI_LCD_DPOT_CTRL)
                /**
                 * backlightOn: turns on the backlight with a specific brightness
                **/
                void backlightOn(uint8_t);
            #endif
            
            #ifdef TWI_LCD_DPOT_CTRL
                /**
                 * setBrightness: sets the brightness level using a digital pot
                 * If no param is passed TWI_LCD_DB_LEVEL is used
                **/
                void setBrightness(void);
                void setBrightness(uint8_t);
            #endif
        #endif
        
            /**
             * setCursor: set cursor a position "index"
            **/
            void setCursor(int);
            
            /**
             * moveToXY: moves the cursor to position (row,column)
            **/
            void moveToXY(uint8_t, uint8_t);
            
            /**
             * Turn off the LCD (will turn off the backlight if control is enabled)
            **/
            void turnOff(void);
            
            /**
             * goToLine: Allows to move at the beginning of a specific line
            **/
            void goToLine(uint8_t);
            
            /**
             * goToNextLine: goes to the next line, wraps arround at the end
            **/
            void goToNextLine(void);
            
            /**
             * goHome: goes to position (0,0)
            **/
            void goHome(void);
            
            /**
             * clearLine: clears the current line
            **/
            void clearLine(void);
            
            /**
             * shiftDisplayLeft: shift all lines of the display one position to the left
            **/
            void shiftDisplayLeft(void);
            
            /**
             * shiftDisplayRight: shift all lines of the display one position to the right
            **/
            void shiftDisplayRight(void);
            
            /**
             * getCurrentLine: returns the current line
            **/
            uint8_t getCurrentLine(void);
            
            /**
             * getCurrentStatus: returns whether the display is on or off
            **/
            bool getCurrentStatus(void);
            
            /**
             * printInteger: writes an interger as text on the lcd
             * The second version is only good for intergers < 99 and will add a leading zero
            **/
            void printInteger(int16_t);
            void printInteger(uint16_t integer, bool leadingZero);
    #endif
        private:
    #if defined(__AVR_ATmega168__) && !defined(TWI_LCD_SMALL)
        #ifdef TWI_LCD_USE_TIMEOUT
            unsigned long   previousMillis;
        #endif
        
        #if defined(TWI_LCD_CTRL) && !defined(TWI_LCD_BL_PWM)
            /**
             * backlightStatus: used to keep track of the backlight status
            **/
            uint8_t     backlightStatus;
        #endif
            
            /**
             * currentLine: keeps track of the current line
            **/
            uint8_t     currentLine;
            
            /**
             * displayStatus: keeps track of whether the display is on or off
            **/
            bool        displayStatus;
    #endif
            /**
             * sendPulse: sends a byte of data with the appropiate Enable pulse
            **/
            void        sendPulse(int);
            
            /**
             * writeToPCF: writes a new byte of data using twi
             *  This function is used to preserve some data through writes
             *  such as when bit3 of the expander is used to control the backlight
            **/
            void        writeToPCF(int);
            
            /**
             * writeCommand: Writes an LCD command
             * @param: value: the value to write
            **/
            void        writeCommand(uint8_t value);
            
            /**
             * checkLCDBusy: reads the busy state bit from the LCD
            **/
            boolean     checkLCDBusy(void);
    };

    /**
     * Define the object's name
    **/
    extern twiLCD LCD;

#endif