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/** A oled i2c class porting from Arduino's OLED_I2C library
 *
 *  @author  Poushen Ou
 *  @version 1.0
 *  @date    17-Jun-2018
 *
 *  This code provide operation for I2C OLED SSD1306
 *
 *  About OLED SSD1306
 *      https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf
 */
#ifndef _OLED_I2C_H_
#define _OLED_I2C_H_

#include "mbed.h"
#include "eeprom.h"

#define LEFT    0
#define RIGHT   9999
#define CENTER  9998

#define SSD1306_128_64

#define SSD1306_ADDR        0x78
#define SSD1306_MEM_SIZE    360
#define SSD1306_WIDTH       72
#define SSD1306_LENGTH      40

#define SSD1306_COMMAND         0x00
#define SSD1306_DATA            0xC0
#define SSD1306_DATA_CONTINUE   0x40

//#define SSD1306_DATA_OUT_OPTIMIZED

// SSD1306 Commandset
// ------------------
// Fundamental Commands
#define SSD1306_SET_CONTRAST_CONTROL        0x81
#define SSD1306_DISPLAY_ALL_ON_RESUME       0xA4
#define SSD1306_DISPLAY_ALL_ON              0xA5
#define SSD1306_NORMAL_DISPLAY              0xA6
#define SSD1306_INVERT_DISPLAY              0xA7
#define SSD1306_DISPLAY_OFF                 0xAE
#define SSD1306_DISPLAY_ON                  0xAF
#define SSD1306_NOP                         0xE3
// Scrolling Commands
#define SSD1306_HORIZONTAL_SCROLL_RIGHT                 0x26
#define SSD1306_HORIZONTAL_SCROLL_LEFT                  0x27
#define SSD1306_HORIZONTAL_SCROLL_VERTICAL_AND_RIGHT    0x29
#define SSD1306_HORIZONTAL_SCROLL_VERTICAL_AND_LEFT     0x2A
#define SSD1306_DEACTIVATE_SCROLL                       0x2E
#define SSD1306_ACTIVATE_SCROLL                         0x2F
#define SSD1306_SET_VERTICAL_SCROLL_AREA                0xA3
// Addressing Setting Commands
#define SSD1306_SET_LOWER_COLUMN                        0x00
#define SSD1306_SET_HIGHER_COLUMN                       0x10
#define SSD1306_MEMORY_ADDR_MODE                        0x20
#define SSD1306_SET_COLUMN_ADDR                         0x21
#define SSD1306_SET_PAGE_ADDR                           0x22
// Hardware Configuration Commands
#define SSD1306_SET_START_LINE                          0x40
#define SSD1306_SET_SEGMENT_REMAP                       0xA0
#define SSD1306_SET_MULTIPLEX_RATIO                     0xA8
#define SSD1306_COM_SCAN_DIR_INC                        0xC0
#define SSD1306_COM_SCAN_DIR_DEC                        0xC8
#define SSD1306_SET_DISPLAY_OFFSET                      0xD3
#define SSD1306_SET_COM_PINS                            0xDA
#define SSD1306_CHARGE_PUMP                             0x8D
// Timing & Driving Scheme Setting Commands
#define SSD1306_SET_DISPLAY_CLOCK_DIV_RATIO             0xD5
#define SSD1306_SET_PRECHARGE_PERIOD                    0xD9
#define SSD1306_SET_VCOM_DESELECT                       0xDB

/** oled_i2c Class Library
 * to provide access interface to OLED screen for mbed
 *
 * Example:
 * @code
 * #include "mbed.h"
 * #include "oled_i2c.h"
 * #include "oled_font.h"
 *
 * // make oled_i2c instance using I2C object.
 * // with default slave address 0x78 (0x3C in 7bit format)
 * // test ok with SSD1306 I2C 128*64 oled screen
 * I2C i2c(dp5,dp27);   // for LPC1114 or LPC1115
 * oled_i2c oled(i2c);
 *
 * int main()
 * {
 *     i2c.frequency(1000 * 1000);
 *     oled.init_oled();
 * 
 *     oled.setFont(BigNumbers);
 *     //oled.print("27", 20, 10);
 *     //oled.printNumI(27, 0, 0);
 *     oled.printNumF(27.45, 2, 0, 0);
 *     oled.setFont(SmallFont);
 *     oled.print("~c", 60, 30);
 *     oled.update();
 *
 *     while(1);
 * }
 * @endcode
 */
class oled_i2c
{
public:
    /** Create a oled_i2c instance connected to specified I2C pins with specified address
     *
     * @param i2c_obj I2C object (instance)
     * @param address (option) I2C-bus slave address
     */
    oled_i2c(I2C &i2c_obj, char address = SSD1306_ADDR);

    /** Destractor */
    ~oled_i2c();

    /** Initialization */
    void init(void);
    
    /** send SSD1306 command 
     *
     * @param a the SSD1306 command byte to send out
     */
    void comm_out(uint8_t a);
    
    /** send many SSD1306 commands in one I2C transaction
     *
     * @param pPage pointer to command buffer
     * @param size the command buffer size
     */
    void comm_page_out(uint8_t* pPage, uint8_t size);
    
    /** send SSD1306 data
     *
     * @param a the SSD1306 data byte to send out
     */
    void data_out(uint8_t a);
    
    /** send many SSD1306 data bytes in one I2c transaction
     *
     * @param pPage pointer to data buffer
     * @param size the data buffer size
     */
    void data_page_out(uint8_t* pPage, uint8_t size);
    
    /** send init command to SSD1306 */
    void init_oled(void);
    
    /** make all pixel on or off acording to screen buffer */
    void pixel_on(void);
    
    /** update screen buffer */
    void update(void);
    
    /** clear screen */
    void clrScr(void);
    
    /** fill screen */
    void fillScr(void);
    
    /** set pixel on coordinate x, y
     *
     * @param x coordinate x (column)
     * @param y coordinate y (row)
     */
    void setPixel(uint16_t x, uint16_t y);
    
    /** clear pixel on coordinate x, y
     *
     * @param x coordinate x (column)
     * @param y coordinate y (row)
     */
    void clrPixel(uint16_t x, uint16_t y);
    
    /** set font type
     *
     * @param font the font to print
     */
    void setFont(const uint8_t* font);
    
    /** print character to coordinate x, y
     *
     * @param c the character to print
     * @param x coordinate x
     * @param y coordinate y
     */
    void print_char(unsigned char c, int x, int y);
    
    /** print string to coordinate x, y
     *
     * @param st the string to print
     * @param x coordinate x
     * @param y coordinate y
     */
    void print(char* st, int x, int y);
    
    /** print integer number to coordinate x, y
     *
     * @param num the integer to be print
     * @param x coordinate x
     * @param y coordinate y
     * @param length the length of integer to be print
     * @param filler the prefix character
     */
    void printNumI(long num, int x, int y, int length=0, char filler=' ');
    
    /** print float number to coordinate x, y
     *
     * @param num the float number to be print
     * @param dec the numbers of digits after point
     * @param x coordinate x
     * @param y coordinate y
     * @param divider should be the point (.)
     * @param length the length of float number to be print
     * @param filler the prefix character
     */
    void printNumF(double num, uint8_t dec, int x, int y, char divider='.', int length=0, char filler=' ');
     

private:
    I2C &i2c;
    char adr;
    eeprom *epm_p;
    eeprom &epm;
    struct _current_font
    {
        const uint8_t* font;
        uint8_t x_size;
        uint8_t y_size;
        uint8_t offset;
        uint8_t numchars;
    } cfont;
    uint8_t scrbuf[SSD1306_MEM_SIZE];
};

#endif