tbx/include/drv/liquid_crystal.h

/*!
 * \file drv/liquid_crystal.h
 * \brief
 *      A liquid crystal display driver
 *
 * \copyright Copyright (C) 2021 Christos Choutouridis <christos@choutouridis.net>
 *
 * <dl class=\"section copyright\"><dt>License</dt><dd>
 * The MIT License (MIT)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 * </dd></dl>
 */

#ifndef TBX_DRV_LIQUID_CRYSTAL_H_
#define TBX_DRV_LIQUID_CRYSTAL_H_

#include <core/core.h>
#include <core/crtp.h>
#include <utils/print.h>

#include <type_traits>
#include <ctime>

namespace tbx {

    /*!
     * \class liquid_crystal
     * \brief
     *      A CRTP driver class for liquid crystal display with parallel interface,
     *      based on Hitachi HD44780 (Samsung KS0066U, or compatible).
     *
     * The driver inherits from Print
     * The Implementation requirements are:
     *  - void bus_impl(data);          To set the 4bit/8bit bus
     *  - void rs_pin_impl(state);      To set/clear RS pin
     *  - void en_pin_impl(state);      To set/clear EN pin
     *  - void power_pin_impl(state);   To set/clear PWR pin
     *  - void bl_pin_impl(state);      To set/clear BackLight pin
     *  - void delay_usec_impl(usec);   To provide delay in usec
     *
     * \tparam Impl_t       The derived class
     * \tparam Lines        The lines of the LCD
     * \tparam Columns      The coluns of the LCD
     */
    template <typename Impl_t, size_t Lines, size_t Columns, size_t BusSize =4>
    class liquid_crystal : public Print<liquid_crystal<Impl_t, Lines, Columns, BusSize>, char>{
        friend Print<liquid_crystal, char>;
        _CRTP_IMPL(Impl_t);
        static_assert((BusSize == 4) || (BusSize == 8), "BusSize must be either 4 or 8.");

    public:

        /*!
         * Public enumerator to be used as argument to the init() function.
         * Selects the font size and thus the number of active lines
         */
        enum class FontSize :uint8_t { dots_5x8, dots_5x10 };
    private:

        // Commands
        constexpr static uint8_t Cmd_cls        = 0x01;
        constexpr static uint8_t Cmd_RetHome    = 0x02;
        constexpr static uint8_t Cmd_EntryMode  = 0x04;
        constexpr static uint8_t Cmd_DispCtrl   = 0x08;
        constexpr static uint8_t Cmd_Shift      = 0x10;
        constexpr static uint8_t Cmd_FunSet     = 0x20;
        constexpr static uint8_t Cmd_SetGRamAddr= 0x40;
        constexpr static uint8_t Cmd_SetDRamAddr= 0x80;

        /*
         *  Entry Mode Set -----> 0  0  0  0      0  1  I/D  S
         *  ----------------------------------------------------
         *  I/D = 1 Increment Curs
         *        0 Decrement
         *  S   = 1 Display shift
         *        0 Not
         */
        constexpr static uint8_t Entry_Right    = 0x00;
        constexpr static uint8_t Entry_Left     = 0x02;
        constexpr static uint8_t Entry_ShiftInc = 0x01;
        constexpr static uint8_t Entry_ShiftDec = 0x00;

        /*
         *  DispOnOffControll -->  0  0  0  0     1  D  C  B
         *  -------------------------------------------------
         *  D = Display On
         *  C = Cursor On
         *  B = Blinking On
         */
        constexpr static uint8_t Display_On     = 0x04;
        constexpr static uint8_t Display_Off    = 0x00;
        constexpr static uint8_t Cursor_On      = 0x02;
        constexpr static uint8_t Cursor_Off     = 0x00;
        constexpr static uint8_t Blink_On       = 0x01;
        constexpr static uint8_t Blink_Off      = 0x00;

        /*
         *  Cursor/Display Shift --> 0  0  0  1   S/C R/L  x  x
         *  ---------------------------------------------------
         *  S/C = 1 Display Shift
         *        0 Cursor Shift
         *  R/L = 1 Shift Right
         *        0 Shift left
         */
        constexpr static uint8_t DisMove_Display= 0x08;
        constexpr static uint8_t DisMove_Cursor = 0x00;
        constexpr static uint8_t DisMove_Right  = 0x04;
        constexpr static uint8_t DisMove_Left   = 0x00;

        /*
         *  FunctionSet     ------>  0  0  1 DL   N   F   x  x
         *  ---------------------------------------------------
         *  DL = 1 8bit
         *       0 4bit
         *  N  = 1 2 lines
         *       0 1 line
         *  F  = 1 5x10 dots
         *       0 5x8 dots
         */
        constexpr static uint8_t FunSet_8bitMode= 0x10;
        constexpr static uint8_t FunSet_4bitMode= 0x00;
        constexpr static uint8_t FunSet_2Line   = 0x08;
        constexpr static uint8_t FunSet_1Line   = 0x00;
        constexpr static uint8_t FunSet_5x10dots= 0x04;
        constexpr static uint8_t FunSet_5x8dots = 0x00;

        /*!
         * \brief
         *      Helper class to keep track of the display cursor. As we dont read the cursor
         *      position on the display, in order to implement backspace operation we need to
         *      keep track the cursor position manually.
         */
        struct Cursor {
            uint8_t inc_x() noexcept {
                if (++x_ > Columns)  x_ =1;
                return x_;
            }
            uint8_t dec_x() noexcept {
                if (--x_ < 1)        x_ =Columns;
                return x_;
            }
            uint8_t inc_y () noexcept {
                if (++y_ > max_lines) y_ =1;
                return y_;
            }
            uint8_t dec_y () noexcept {
                if (--y_ < 1)        y_ =max_lines;
                return y_;
            }
            uint8_t operator++() noexcept { return inc_x(); }
            uint8_t operator--() noexcept { return dec_x(); }
            void set(uint8_t x, uint8_t y) noexcept {
                x_ = x;
                y_ = y;
            }
            uint8_t get_x() noexcept { return x_; }
            uint8_t get_y() noexcept { return y_; }
            void set_lines (uint8_t l) noexcept { max_lines = l; }
        private:
            uint8_t x_, y_;
            uint8_t max_lines;
        };
    private:
        //! \name Implementation requirements
        //! @{
        void BUS (uint8_t data)   { impl().bus_impl(data); }
        void RS_Pin (bool state)  { impl().rs_pin_impl(state); }
        void EN_Pin (bool state)  { impl().en_pin_impl(state); }
        void PWR_Pin (bool state) { impl().power_pin_impl(state); }
        void BL_Pin (bool state)  { impl().bl_pin_impl(state); }
        void delay_usec(size_t usec) {
            impl().delay_usec_impl(usec);
        }
        //! @}

        //! \name Print interface requirements
        //! @{
        size_t write_impl (const char* str, size_t size) {
            size_t ret =0;
            while (*str && ret < size) {
                putchar (*str++);
                ++ret;
            }
            return ret;
        }
        size_t write_impl (const char ch) {
            return (putchar(ch) == ch) ? 1:0;
        }
        //! @}

    protected:
        //! \name Object lifetime
        //! @{
        liquid_crystal() noexcept   = default;      //!< Construct from derived only
        //~liquid_crystal()           = default;
        liquid_crystal(const liquid_crystal&)               = delete;   //!< No copies
        liquid_crystal& operator= (const liquid_crystal&)   = delete;   //!< No copies
        //! @}

    private:
        //! Send enable pulse to display
        void pulse_enable () {
            EN_Pin(0);
            delay_usec (2);     // time to settle BUS pin voltages
            EN_Pin(1);
            delay_usec (2);     // >450 [nsec]
            EN_Pin(0);
            delay_usec (50);    // > 37 [usec]
        }

        //! Writes 4/8bit data to display and pulse the EN pin
        //! \param  data    The data to write
        void write_bits (uint8_t data) {
            if constexpr (BusSize == 4) BUS (data & 0x0F);
            else                        BUS (data);
            pulse_enable ();
        }

        /*!
         * \brief
         *      Sends commands or character to display by controlling RS pin
         * \param data  The data to send
         * \param mode  Character/command mode (RS pin state)
         */
        void send (uint8_t data, uint8_t mode) {
            RS_Pin (mode);
            if constexpr (BusSize == 4) {
                write_bits (data >> 4);
                write_bits (data & 0x0F);
            } else {
                write_bits (data);
            }
        }
        //! Send a command to display
        void command (uint8_t c)   { send(c, 0); }
        //! Send a character to display
        void character (uint8_t c) { send(c, 1); }

    public:
        //! \name Public API
        //! @{

        /*!
         * \brief
         *      Initialize the display. After construction the object is valid but reflects the init state
         *      of display configuration. In order for the display to be functional it needs initialization.
         *      So the user has to call this function. This function requires a settled environment, so usually
         *      its called after main().
         * \param mode      4bit or 8bit mode
         * \param fontSize  5x8 or 5x10 dots font size.
         */
        void init (FontSize fontSize =FontSize::dots_5x8) {
            disp_mode_    = disp_mode_init_;    // Set values to LCD's startup configuration
            disp_control_ = disp_control_init_;
            disp_function_=disp_function_init_;

            // Read user configuration
            if constexpr (BusSize == 4)
                // note: keep this runtime, so the disp_function reflects lcd's configuration state
                disp_function_ &= ~FunSet_8bitMode;
            else
                disp_function_ |= FunSet_8bitMode;

            if (fontSize == FontSize::dots_5x10) {
                disp_function_ |= FunSet_5x10dots;
                disp_function_ &= ~FunSet_2Line;
                cursor_.set_lines(Lines>>1);
            } else {
                disp_function_ &= ~FunSet_5x10dots;
                disp_function_ |= FunSet_2Line;
                cursor_.set_lines(Lines);
            }

            // start with All-zeros
            BUS (0);  EN_Pin(0); RS_Pin(0); BL_Pin(0);

            delay_usec(100000);
            if constexpr (BusSize == 4) {
                // 4bit BUS
                write_bits (0x03);                      // 1t try
                delay_usec(20000);
                write_bits (0x03);                      // 2nd try
                delay_usec(5000);
                write_bits (0x03);                      // 3rd try
                delay_usec(5000);
                write_bits (0x02);                      // We set 4 bit interface
                delay_usec (10000);
            } else {
                // 8bit BUS
                write_bits (Cmd_FunSet | disp_function_);   // 1st try
                delay_usec(20000);
                write_bits (Cmd_FunSet | disp_function_);   // 2nd try
                delay_usec(5000);
                write_bits (Cmd_FunSet | disp_function_);   // 3rd try
                delay_usec(5000);
            }
            command (Cmd_FunSet | disp_function_);      // Finally we set #lines and font size
            delay_usec(5000);

            command (Cmd_DispCtrl | Display_Off);   // Display off
            delay_usec(5000);
            command (Cmd_cls);                      // Clear screen
            delay_usec(5000);
            command (Cmd_EntryMode | disp_mode_);   // Entry mode set
            delay_usec(5000);

            command (Cmd_RetHome);                  // Return home
            delay_usec(10000);
            display(true);                          // Finally display On, done.
            cursor_.set(1, 1);
        }

        //! Utility function to enable/disable power to display. This has an effect IFF there is a
        //! power pin on the board
        void power (bool en) {
            PWR_Pin(en);
        }

        //! Utility function to enable/disable backlight. This has an effect IFF there is a
        //! backlight pin on the board
        void backlight (bool en) {
            BL_Pin(en);
        }

        //! Utility function to send on/off command to display.
        void display (bool en) {
            if (en)     disp_control_ |= Display_On;
            else        disp_control_ &= ~Display_On;

            command (Cmd_DispCtrl | disp_control_);
            delay_usec(100);
        }

        //! Utility function to enable/disable display cursor.
        void cursor (bool en) {
            if (en)     disp_control_ |= Cursor_On;
            else        disp_control_ &= ~Cursor_On;

            command (Cmd_DispCtrl | disp_control_);
            delay_usec(100);
        }

        //! Utility function to enable/disable cursor blinking.
        void blink (bool en) {
            if (en)     disp_control_ |= Blink_On;
            else        disp_control_ &= ~Blink_On;

            command (Cmd_DispCtrl | disp_control_);
            delay_usec(100);
        }

        //! Utility function to enable/disable autoscroll.
        void autoscroll (bool en) {
            if (en)     disp_mode_ |= Entry_ShiftInc;
            else        disp_mode_ &= ~Entry_ShiftInc;

            command (Cmd_EntryMode | disp_mode_);
            delay_usec(100);
        }

        /*!
         * \brief
         *      Tool to set display cursor
         * \param x     The column position (starting with 1)
         * \param y     The line position (starting with 1 at the top of the display)
         */
        void set_cursor (uint8_t x, uint8_t y) {
            uint8_t offset;
            switch (y) {
               default:
               case 1: offset = 0x0;   break;
               case 2: offset = 0x40;  break;
               case 3: offset = 0x0  + Columns; break;
               case 4: offset = 0x40 + Columns; break;
            }
            command( Cmd_SetDRamAddr | offset | (x-1));
            cursor_.set(x, y);
        }

        //! Utility function to set left to right entry mode.
        //! \note
        //!     This is the default
        void set_left_to_right () {
            disp_mode_ |= Entry_Left;
            command (Cmd_EntryMode | disp_mode_);
            delay_usec(100);
        }

        //! Utility function to set right to left entry mode.
        void set_right_to_left () {
            disp_mode_ &= ~Entry_Left;
            command (Cmd_EntryMode | disp_mode_);
            delay_usec(100);
        }

        //! Command to scroll display left one position
        void scroll_left () {
            command (Cmd_Shift | DisMove_Display | DisMove_Left);
        }

        //! Command to scroll display right one position
        void scroll_right () {
            command (Cmd_Shift | DisMove_Display | DisMove_Right);
        }

        //! Clears the display and return home
        void clear() {
            command (Cmd_cls);
            cursor_.set(1, 1);
            delay_usec(2000);
        }

        //! return home without clearing the display
        void home() {
            command (Cmd_RetHome);
            cursor_.set(1, 1);
            delay_usec(2000);
        }

        /*!
         * \brief
         *      Create custom character and store it to LCD.
         * \param location  The location to store the character [0..7] allowed
         * \param charmap   The character map buffer with the font
         */
        void create_char (uint8_t location, uint8_t charmap[]) {
            location &= 0x7;        // we only have 8 locations 0-7
            command(Cmd_SetGRamAddr | (location << 3));
            for (size_t i=0; i<8; ++i) {
                character(charmap[i]);
            }
        }

        /*!
         * \brief
         *    Send an ascii character to liquid crystal display.
         * \param  ch     the character to send
         * \return the character send.
         *
         * \note
         *    This is the driver's "putchar()" functionality to glue.
         *    Tailor this function to redirect stdout to display.
         */
        int putchar (int ch) {
            // LCD Character dispatcher
            switch (ch) {
                case 0:
                    // don't send null termination to device
                    break;
                case '\n':
                    cursor_.inc_y();
                    set_cursor (1, cursor_.get_y());
                    break;
                case '\r':
                    set_cursor (1, cursor_.get_y());
                    break;
                case '\v':
                    home ();
                    break;
                case '\f':
                    set_cursor (1, 1);
                    break;
                case '\b':
                    --cursor_;
                    set_cursor (cursor_.get_x(), cursor_.get_y());
                    character (' ');
                    --cursor_;
                    set_cursor (cursor_.get_x(), cursor_.get_y());
                    break;
                default:
                    character (ch);
                    ++cursor_;
                    break;
            }
            //ANSI C (C99) compatible mode
            return ch;
        }
        //! @}

    private:
        //! \name Data members
        //! @{

        //! The init entry mode of the display after power up
        static constexpr uint8_t disp_mode_init_    = Entry_Left | Entry_ShiftDec;
        //! The init control mode of the display after power up
        static constexpr uint8_t disp_control_init_ = Display_Off | Cursor_Off | Blink_Off;
        //! The init function set of the display after power up
        static constexpr uint8_t disp_function_init_= FunSet_8bitMode | FunSet_1Line | FunSet_5x8dots;

        Cursor cursor_{};
        uint8_t disp_mode_ {disp_mode_init_};
        uint8_t disp_control_ {disp_control_init_};
        uint8_t disp_function_ {disp_function_init_};
        /*!
         * \note
         *  When the display powers up, it is configured as follows:
         *  1. Display clear
         *  2. Function set: 0x10
         *     DL = 1; 8-bit interface data
         *     N = 0; 1-line display
         *     F = 0; 5x8 dot character font
         *  3. Display on/off control: 0x00
         *     D = 0; Display off
         *     C = 0; Cursor off
         *     B = 0; Blinking off
         *  4. Entry mode set: 0x02
         *     I/D = 1; Increment by 1
         *     S = 0; No shift
         */

        //! @}
    };

}

#endif /* TBX_DRV_LIQUID_CRYSTAL_H_ */