/*
 * Author: Josh Holtrop
 * Date: 2009-05-03
 * 
 * This module provides a C++ object-oriented interface to a
 * Noritake itron Vacuum Fluorescent Display model CU20025ECPB-W1J
 * that my friend Mike Zwagerman let me borrow.
 *
 * It is connected to my PC's parallel port as follows:
 * CN1 Pin  Parallel Port Pin
 * Gnd   1  18  Ground
 * RS    4  2   Data0
 * R/|W| 5  3   Data1
 * E     6  4   Data2
 * DB4  11  5   Data3
 * DB5  12  6   Data4
 * DB6  13  7   Data5
 * DB7  14  8   Data6
 *
 * Additionally, CN1 pin 1 (ground) is connected to an independent 5 volt
 * power supply's ground, and CN1 pin 2 (Vcc) is connected to the
 * independent power supply's +5V line.
 *
 */

#ifndef VFD_H
#define VFD_H VFD_H

#include <string>

class VFD
{
    public:
        static const unsigned char SHIFT_CURSOR = 0;
        static const unsigned char SHIFT_DISPLAY = 1;
        static const unsigned char LEFT = 0;
        static const unsigned char RIGHT = 1;
        static const unsigned char OFF = 0;
        static const unsigned char ON = 1;
        static const unsigned char ADDRESS_LINE1 = 0x00;
        static const unsigned char ADDRESS_LINE2 = 0x40;

        VFD();
        ~VFD();
        bool connect(const std::string & parport = "/dev/parport0");
        void disconnect();

        void displayClear();
        void cursorHome();
        void entryModeSet(unsigned char address_direction,  /* LEFT|RIGHT */
                          unsigned char display_shift);     /* ON|OFF */
        void setDisplay(unsigned char display,              /* ON|OFF */
                        unsigned char cursor,               /* ON|OFF */
                        unsigned char cursor_blink);        /* ON|OFF */
        void shift(unsigned char shift_display,             /* ON|OFF */
                   unsigned char direction);                /* LEFT|RIGHT */
        void setCGAddress(unsigned char address);
        void setAddress(unsigned char address);
        void writeByte(unsigned char data);
        void write(const std::string & str);

    protected:
        static const unsigned char RW_WRITE = 0;
        static const unsigned char RW_READ = 1;
        static const unsigned char E_DISABLE = 0;
        static const unsigned char E_ENABLE = 1;
        static const unsigned char RS_COMMAND = 0;
        static const unsigned char RS_DATA = 1;
        static const unsigned char PP_OFFSET_RS = 0;
        static const unsigned char PP_OFFSET_RW = 1;
        static const unsigned char PP_OFFSET_E = 2;
        static const unsigned char PP_OFFSET_DATA = 3;
        static const int INIT_DELAY = 10 * 1000;
        static const int DISPLAY_CLEAR_DELAY = 2300;

        void sendByte(unsigned char rs, unsigned char dat);
        void sendNibble(unsigned char rs, unsigned char dat);
        void setPPLines(unsigned char bits);

        int m_ppfd;     /* parallel port file descriptor */
};

#endif