SSD1308.h

00001 /** @file SSD1308 I2C device class header file
00002  *   Based on Solomon Systech SSD1308 datasheet, rev. 1, 10/2008
00003  *   The SSD1308 is used for example in the Seeed 128x64 OLED Display
00004  *   http://www.seeedstudio.com/depot/grove-oled-display-12864-p-781.html?cPath=163_167
00005  */
00006 // The original code by Andrew Schamp is using (and has been submitted as a part of) Jeff Rowberg's I2Cdevlib library,
00007 // which should (hopefully) always be available at https://github.com/jrowberg/i2cdevlib
00008 // Some parts also mashed up from Graphic Library for driving monochrome displays based on the PCD8544,
00009 // Copyright (c) 2011, Wim De Roeve, who in turn did partial port of code found on
00010 // http://serdisplib.sourceforge.net/ser/pcd8544.html#links and by Petras Saduikis <petras@petras.co.uk>
00011 //
00012 // Changelog:
00013 //   2011-08-25 - Initial release by Andrew Schamp <schamp@gmail.com>
00014 //   2012-06-19 - Ported to mbed and optimised (WH)
00015 //   2013-07-12 - Minor comment fix and placeholder for SSD1306 (WH)
00016 //   2015-01-01 - Switch for optimised I2C calls to test on F401 (WH)
00017 //             
00018 /* 
00019 ================================================================================
00020 I2Cdev device library code is placed under the MIT license
00021 Copyright (c) 2011 Andrew Schamp
00022 Copyright (c) 2012,2013 WH (mbed port)
00023 
00024 Permission is hereby granted, free of charge, to any person obtaining a copy
00025 of this software and associated documentation files (the "Software"), to deal
00026 in the Software without restriction, including without limitation the rights
00027 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00028 copies of the Software, and to permit persons to whom the Software is
00029 furnished to do so, subject to the following conditions:
00030 
00031 The above copyright notice and this permission notice shall be included in
00032 all copies or substantial portions of the Software.
00033 
00034 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00035 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00036 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00037 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00038 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00039 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00040 THE SOFTWARE.
00041 ================================================================================
00042 */
00043 
00044 #ifndef SSD1308_H
00045 #define SSD1308_H
00046 
00047 // This is the I2C address (8 bit)
00048 //  There are two possible addresses: with D/C# (pin 13) grounded, the address is 0x78,
00049 //  with D/C# tied high it is 0x7A. Assume grounded by default.
00050 #define SSD1308_SA0                0x78
00051 #define SSD1308_SA1                0x7A
00052 #define SSD1308_DEF_SA             SSD1308_SA0
00053 
00054 // Display dimensions
00055 #define ROWS                       64
00056 #define COLUMNS                    128
00057 #define PAGES                      (ROWS / 8)
00058 #define MAX_PAGE                   (PAGES - 1)
00059 #define MAX_ROW                    (ROWS - 1)
00060 #define MAX_COL                    (COLUMNS - 1)
00061 
00062 // Character dimensions 8x8 font
00063 #define CHARS                      (COLUMNS / FONT8x8_WIDTH)
00064 
00065 // Command and Datamode 
00066 #define COMMAND_MODE               0x80 // continuation bit is set!
00067 #define DATA_MODE                  0x40
00068 
00069 // Commands and Parameter defines
00070 #define SET_LOWER_COLUMN           0x00 // | with lower nibble  (Page mode only)
00071 #define SET_HIGHER_COLUMN          0x10 // | with higher nibble (Page mode only)
00072 
00073 #define HORIZONTAL_ADDRESSING_MODE 0x00
00074 #define VERTICAL_ADDRESSING_MODE   0x01
00075 #define PAGE_ADDRESSING_MODE       0x02
00076 #define SET_MEMORY_ADDRESSING_MODE 0x20 // takes one byte as given above
00077 
00078 #define SET_COLUMN_ADDRESS         0x21 // takes two bytes, start address and end address of display data RAM
00079 #define SET_PAGE_ADDRESS           0x22 // takes two bytes, start address and end address of display data RAM
00080 
00081 // Command maybe unsupported by SSD1308
00082 #define FADE_INTERVAL_8_FRAMES     0x00
00083 #define FADE_INTERVAL_16_FRAMES    0x01
00084 #define FADE_INTERVAL_24_FRAMES    0x02
00085 #define FADE_INTERVAL_32_FRAMES    0x03
00086 #define FADE_INTERVAL_64_FRAMES    0x07
00087 #define FADE_INTERVAL_128_FRAMES   0x0F
00088 #define FADE_BLINK_DISABLE         0x00
00089 #define FADE_OUT_ENABLE            0x20
00090 #define BLINK_ENABLE               0x30
00091 #define SET_FADE_BLINK             0x23 // takes one byte
00092                                         //  bit5-4 = 0, fade/blink mode
00093                                         //  bit3-0 = Time interval in frames 
00094 
00095 #define SET_DISPLAY_START_LINE     0x40 // | with a row number 0-63 to set start row. (Reset = 0)
00096 
00097 #define SET_CONTRAST               0x81 // takes one byte, 0x00 - 0xFF
00098 
00099 #define SET_SEGMENT_REMAP_0        0xA0 // column address 0 is mapped to SEG0 (Reset)
00100 #define SET_SEGMENT_REMAP_127      0xA1 // column address 127 is mapped to SEG0
00101 
00102 #define SET_DISPLAY_GDDRAM         0xA4 // restores display to contents of RAM
00103 #define SET_ENTIRE_DISPLAY_ON      0xA5 // turns all pixels on, does not affect RAM
00104 
00105 #define SET_NORMAL_DISPLAY         0xA6 // a databit of 1 indicates pixel 'ON'
00106 #define SET_INVERSE_DISPLAY        0xA7 // a databit of 1 indicates pixel 'OFF'
00107 
00108 #define SET_MULTIPLEX_RATIO        0xA8 // takes one byte, from 16xMUX to 64xMUX (MUX Ratio = byte+1; Default 64)
00109 
00110 #define EXTERNAL_IREF              0x10
00111 #define INTERNAL_IREF              0x00
00112 #define SET_IREF_SELECTION         0xAD // sets internal or external Iref
00113 
00114 #define SET_DISPLAY_POWER_OFF      0xAE
00115 #define SET_DISPLAY_POWER_ON       0xAF
00116 
00117 #define PAGE0                      0x00
00118 #define PAGE1                      0x01
00119 #define PAGE2                      0x02
00120 #define PAGE3                      0x03
00121 #define PAGE4                      0x04
00122 #define PAGE5                      0x05
00123 #define PAGE6                      0x06
00124 #define PAGE7                      0x07
00125 #define SET_PAGE_START_ADDRESS     0xB0 // | with a page number to get start address (Page mode only)
00126 
00127 #define SET_COMMON_REMAP_0         0xC0 // row address  0 is mapped to COM0 (Reset)
00128 #define SET_COMMON_REMAP_63        0xC8 // row address 63 is mapped to COM0
00129 
00130 #define SET_DISPLAY_OFFSET         0xD3 // takes one byte from 0-63 for vertical shift, Reset = 0
00131 
00132 #define SET_DISPLAY_CLOCK          0xD5 // takes one byte
00133                                         //  bit7-4 = Osc Freq DCLK (Reset = 1000b) 
00134                                         //  bit3-0 = Divide ration (Reset = oooob, Ratio = 1)   
00135 
00136 #define SET_PRECHARGE_TIME         0xD9 // takes one byte
00137                                         //  bit7-4 = Phase2, upto 15 DCLKs (Reset = 0010b) 
00138                                         //  bit3-0 = Phase1, upto 15 DCLKs (Reset = 0010b)   
00139 
00140                                        
00141 #define COMMON_BASE                0x02 // 
00142 #define COMMON_SEQUENTIAL          0x00 // Sequential common pins config
00143 #define COMMON_ALTERNATIVE         0x10 // Odd/Even common pins config (Reset)
00144 #define COMMON_LEFTRIGHT_NORMAL    0x00 // LeftRight Normal (Reset)
00145 #define COMMON_LEFTRIGHT_FLIP      0x20 // LeftRight Flip 
00146 #define SET_COMMON_CONF            0xDA // takes one byte as given above
00147 
00148 
00149 #define VCOMH_DESELECT_0_65_CODE   0x00
00150 #define VCOMH_DESELECT_0_77_CODE   0x20
00151 #define VCOMH_DESELECT_0_83_CODE   0x30
00152 #define SET_VCOMH_DESELECT_LEVEL   0xDB // takes one byte as given above
00153 
00154 #define NOP                        0xE3
00155 
00156 #define SCROLL_INTERVAL_5_FRAMES   0x00
00157 #define SCROLL_INTERVAL_64_FRAMES  0x01
00158 #define SCROLL_INTERVAL_128_FRAMES 0x02
00159 #define SCROLL_INTERVAL_256_FRAMES 0x03
00160 #define SCROLL_INTERVAL_3_FRAMES   0x04
00161 #define SCROLL_INTERVAL_4_FRAMES   0x05
00162 #define SCROLL_INTERVAL_25_FRAMES  0x06
00163 #define SCROLL_INTERVAL_2_FRAMES   0x07
00164 
00165 #define SET_RIGHT_HOR_SCROLL       0x26 // takes 6 bytes: 0x00, PageStart, Scroll_Interval, PageEnd, 0x00, 0xFF
00166 #define SET_LEFT_HOR_SCROLL        0x27 // takes 6 bytes: 0x00, PageStart, Scroll_Interval, PageEnd, 0x00, 0xFF
00167 
00168 #define SET_VERT_RIGHT_HOR_SCROLL  0x29 // takes 5 bytes: 0x00, PageStart, Scroll_Interval, PageEnd, VertOffset
00169 #define SET_VERT_LEFT_HOR_SCROLL   0x2A // takes 5 bytes: 0x00, PageStart, Scroll_Interval, PageEnd, VertOffset
00170 
00171 #define SET_DEACTIVATE_SCROLL      0x2E
00172 #define SET_ACTIVATE_SCROLL        0x2F
00173 
00174 #define SET_VERTICAL_SCROLL_AREA   0xA3 // takes 2 bytes: Rows in Top Area (Reset=0), Rows in Scroll Area (Reset=64)
00175 
00176 
00177 
00178 /** Class to control an SSD1308 based oled Display
00179  *
00180  * Example:
00181  * @code
00182  * #include "mbed.h"
00183  * #include "mbed_logo.h"
00184  * #include "SSD1308.h"
00185  
00186  * //Pin Defines for I2C Bus
00187  * #define D_SDA                  p28
00188  * #define D_SCL                  p27
00189  * I2C i2c(D_SDA, D_SCL);
00190  *
00191  * // Host PC Communication channels
00192  * Serial pc(USBTX, USBRX); // tx, rx
00193  *
00194  * // Instantiate OLED
00195  * SSD1308 oled = SSD1308(i2c, SSD1308_SA0);
00196  * 
00197  * int main() {
00198  *   pc.printf("OLED test start\r");  
00199  *   oled.writeString(0, 0, "Hello World !");
00200  *   //  oled.printf("Hello World !");
00201  * 
00202  *   oled.fillDisplay(0xAA);
00203  *   oled.setDisplayOff();
00204  *   wait(1);   
00205  *   oled.setDisplayOn();
00206  * 
00207  *   oled.clearDisplay();
00208  *   oled.setDisplayInverse();
00209  *   wait(0.5);
00210  *   oled.setDisplayNormal();                                         
00211  *
00212  *   oled.writeBitmap((uint8_t*) mbed_logo);
00213  *
00214  *   pc.printf("OLED test done\r\n");  
00215  * }
00216  *
00217  * @endcode
00218  */
00219 class SSD1308 : public Stream {
00220   public:
00221     
00222 /**
00223   *@brief Constructor
00224   *@param I2C &i2c reference to i2c,
00225   *@param uint8_t deviceAddress slaveaddress (8bit to use for the controller (0x78 by default, assumes D/C# (pin 13) grounded)
00226  */    
00227     SSD1308(I2C &i2c, uint8_t address = SSD1308_DEF_SA);
00228 
00229 // High Level methods
00230 
00231 /** @brief High level Init, most settings remain at Power-On reset value
00232  */
00233     void initialize();
00234 
00235 /** @brief clear the display
00236 */
00237     void clearDisplay();
00238 
00239 
00240 /** @brief fill the display
00241  *  @param uint8_t pattern fillpattern vertical patch or 8 bits 
00242  *  @param uint8_t start_page begin page   (0..MAX_PAGE)
00243  *  @param uint8_t end_page   end page     (start_page..MAX_PAGE)                     
00244  *  @param uint8_t start_col  begin column (0..MAX_COL)
00245  *  @param uint8_t end_col    end column   (start_col..MAX_COL)
00246 */ 
00247     void fillDisplay(uint8_t pattern = 0x00,
00248                      uint8_t start_page=0, uint8_t end_page=MAX_PAGE,
00249                      uint8_t start_col=0, uint8_t end_col=MAX_COL);
00250 
00251 
00252 /** @brief write a bitmap to the display
00253  *  @param uint8_t* data pointer to bitmap
00254  *  @param uint8_t start_page begin page   (0..MAX_PAGE)
00255  *  @param uint8_t end_page   end page     (start_page..MAX_PAGE)                     
00256  *  @param uint8_t start_col  begin column (0..MAX_COL)
00257  *  @param uint8_t end_col    end column   (start_col..MAX_COL)
00258 */  
00259     void writeBitmap(uint8_t* data,
00260                      uint8_t start_page=0, uint8_t end_page=MAX_PAGE,
00261                      uint8_t start_col=0, uint8_t end_col=MAX_COL);
00262     
00263 /** @brief write a level meter to the display, Width is (PRG_MAX_SCALE + 2) pixels
00264  *  @param uint8_t page begin page   (0..MAX_PAGE)
00265  *  @param uint8_t col  begin column (0..MAX_COL)
00266  *  @param int percentage value      (0..100)
00267 */
00268     void writeProgressBar(uint8_t page, uint8_t col, int percentage);
00269 
00270 
00271 /** @brief write a level meter to the display, Width is (PRG_MAX_SCALE + 2) pixels
00272  *  @param uint8_t page begin page   (0..MAX_PAGE)
00273  *  @param uint8_t col  begin column (0..MAX_COL)
00274  *  @param int percentage value      (0..100)
00275 */
00276     void writeLevelBar(uint8_t page, uint8_t col, int percentage);
00277 
00278     //void setXY(uint8_t, uint8_t y);
00279     
00280     // Select inverted or normal text    
00281     void setInverted(bool inverted) { _inverted = inverted; };    
00282         
00283 /** @brief Write single character to the display using the 8x8 fontable
00284  *  @brief Start at current cursor location
00285  *  @param char chr character to write
00286 */ 
00287     void writeChar(char chr);  
00288     
00289 /** @brief Write large character (16x24 font)
00290  *  @param uint8_t row  row number    (0...MAX_ROW)
00291  *  @param uint8_t col  column number (0...MAX_COL)
00292  *  @param char chr     Used for displaying numbers 0 - 9 and '+', '-', '.'
00293  */   
00294     void writeBigChar(uint8_t row, uint8_t col, char chr);      
00295     
00296 /** @brief Write a string to the display using the 8x8 font
00297  *  @brief Start at selected cursor location, text will wrap around until it is done
00298  *  @param uint8_t row  row number    (0...ROWS/FONT_HEIGHT)
00299  *  @param uint8_t col  column number (0...COLUMNS/FONT_WIDTH)
00300  *  @param const char * text pointer to text
00301  */   
00302     void writeString(uint8_t row, uint8_t col, const char* txt);
00303     
00304     // Stream implementation - provides printf() interface
00305     // You would otherwise be forced to use writeChar() or writeString()
00306     virtual int _putc(int value) { writeChar(value); return 1; };
00307     virtual int _getc() { return -1; };
00308    
00309 // Future extension with graphics features
00310     // this must be defined by the subclass
00311 //    virtual void drawPixel(int16_t x, int16_t y, uint16_t color) = 0;
00312     
00313 // Medium Level methods
00314 
00315 /** @brief Set Horizontal Addressing Mode (cursor incr left-to-right, top-to-bottom)
00316  * 
00317  */
00318     void setHorizontalAddressingMode();
00319     
00320 /** @brief Set Vertical Addressing Mode  (cursor incr top-to-bottom, left-to-right)
00321  * 
00322  */
00323     void setVerticalAddressingMode();
00324     
00325 /** @brief Set Page Addressing Mode  (cursor incr left-to-right)
00326  * 
00327  */
00328     void setPageAddressingMode();
00329         
00330 /** @brief Set Addressing Mode
00331  *  @param uint8_t mode 
00332  */
00333     void setMemoryAddressingMode(uint8_t mode);
00334 
00335 
00336 /** 
00337  *  @brief Set Column Start (for Page Addressing Mode only)
00338  *  @param uint8_t column column start (valid range 0..MAX_COLS)
00339  */    
00340     void setColumnStartForPageAddressingMode(uint8_t column);
00341     
00342 /** 
00343  *  @brief Set Page Start (for Page Addressing Mode only)
00344  *  @param uint8_t page page start (valid range PAGE0 - PAGE7)
00345  */    
00346     void setPageStartForPageAddressingMode(uint8_t page);
00347    
00348 
00349 
00350 /** @param uint8_t start startcolumn (valid range 0..MAX_COL)
00351  *  @param uint8_t end   endcolumn   (valid range start..MAX_COL)
00352  */   
00353     void setColumnAddress (uint8_t start, uint8_t end);
00354     
00355 /** @param uint8_t start startpage (valid range 0..MAX_PAGE)
00356  *  @param uint8_t end   endpage   (valid range start..MAX_PAGE)
00357  */  
00358     void setPageAddress (uint8_t start, uint8_t end);
00359     
00360 
00361 /** 
00362  *  @brief Set Display StartLine, takes one byte, 0x00-0x3F
00363  *  @param uint8_t line startline (valid range 0..MAX_ROWS)
00364  */  
00365     void setDisplayStartLine(uint8_t line);
00366     
00367 /** @brief Set Contrast
00368  *  @param uint8_t contrast (valid range 0x00 (lowest) - 0xFF (highest))
00369 */    
00370     void setContrastControl(uint8_t contrast);
00371 
00372 
00373 /** @brief Shows All Pixels On
00374  */
00375     void setEntireDisplayOn();
00376     
00377 /** @brief Shows Pixels as RAM content
00378  */
00379     void setEntireDisplayRAM();
00380     
00381 /** @brief Shows Pixels On or as RAM content
00382  *  @param bool on (true is All on, false is RAM content)
00383  */
00384     void setEntireDisplay(bool on);
00385     
00386  
00387     // @brief Set Display line MPX Ratio, takes one byte, 0x00-0x3F
00388     // @param uint8_t lines (valid range 0..MAX_ROWS)
00389     void setMultiplexRatio(uint8_t lines);
00390 
00391 
00392 /** @brief Sets Internal Iref
00393  */
00394     void setInternalIref();
00395 
00396 /** @brief Sets External Iref (default)
00397  */   
00398     void setExternalIref();
00399 
00400 
00401 /** @brief Enable Display
00402 */    
00403     void setDisplayOn();
00404 
00405 /** @brief Disable Display
00406 */     
00407     void setDisplayOff();
00408 
00409 /** @brief Enable or Disable Display
00410  *  @param bool on
00411  */    
00412     void setDisplayPower(bool on);
00413 
00414 /** @brief Show White pixels on Black background
00415  */ 
00416     void setDisplayNormal();
00417 
00418 /** @brief Show Black pixels on White background
00419  */   
00420     void setDisplayInverse();
00421 
00422 /** @brief Blink display by fading in and out over a set number of frames
00423  *  @param bool on
00424  */
00425     void setDisplayBlink(bool on);  
00426     
00427 /** @brief Fade out display in set number of frames
00428  *  @param bool on
00429  */        
00430     void setDisplayFade(bool on);    
00431     
00432 /** @brief Display Flip (Left/Right, Up/Down)
00433  *  @param bool left flip Left/Right
00434  *  @param bool down flip Up/Down
00435  */  
00436     void setDisplayFlip(bool left, bool down);
00437 
00438     // Set vertical shift by COM from 0 - 63 (0x00 - 0x3F) (Reset = 0x00)
00439     void setDisplayOffset(uint8_t offset);
00440     
00441     // Oscillator freq 0x00-0x0F (reset 0x08)
00442     // Divide ratio 0x00-0x0F, value +1 (reset 0x00)
00443     void setDisplayClock(uint8_t divideRatio, uint8_t oscFreq);
00444     
00445     // Phase1 0x01-0x0F period of up to 15 DCLK clocks (reset 0x02, 0 is invalid)
00446     // Phase2 0x01-0x0F period of up to 15 DCLK clocks (reset 0x02, 0 is invalid)
00447     void setPrechargePeriod(uint8_t phase1, uint8_t phase2);
00448     
00449     // See defines above for levels
00450     void setVcomhDeselectLevel(uint8_t level);
00451 
00452 
00453     // Command for no-operation
00454     void nop();
00455     
00456 
00457 /** @brief Horizontal scroll by one column per interval
00458  *  @param bool left select Left/Right scroll
00459  *  @param uint8_t start_page begin page   (0..MAX_PAGE)
00460  *  @param uint8_t end_page   end page     (start_page..MAX_PAGE)                     
00461  *  @param uint8_t interval   scroll interval in frames (see codes above)                      
00462  */  
00463     void setContinuousHorizontalScroll(bool left, uint8_t start_page, uint8_t end_page, uint8_t interval);
00464 
00465 
00466 /** @brief Horizontal and Vertical scroll by one column per interval
00467  *  @param bool left select Left/Right scroll
00468  *  @param uint8_t start_page begin page   (0..MAX_PAGE)
00469  *  @param uint8_t end_page   end page     (start_page..MAX_PAGE)                     
00470  *  @param uint8_t offset     vert offset  (0x01..0x63)                       
00471  *  @param uint8_t interval   scroll interval in frames (see codes above)                       
00472  */  
00473     void setContinuousVerticalAndHorizontalScroll(bool left, uint8_t start_page, uint8_t end_page, 
00474                                                   uint8_t offset, uint8_t interval);
00475     
00476 /** @brief Activate or Deactivate Horizontal and Vertical scroll
00477  *  @brief Note: after deactivating scrolling, the RAM data needs to be rewritten
00478  *  @param bool on activate scroll 
00479  */  
00480     void setDisplayScroll(bool on);
00481     
00482 
00483 /** @brief Set Vertical scroll area
00484  *  @param uint8_t topRowsFixed      fixed rows   (0..MAX_ROW)                     
00485  *  @param uint8_t scrollRowsoffset  scroll rows  (topRowsFixed..MAX_ROW)                       
00486  */  
00487     void setVerticalScrollArea(uint8_t topRowsFixed, uint8_t scrollRows); 
00488   
00489   private:
00490 
00491 // Low Level methods
00492 
00493 /** @brief Write command that has no parameters
00494 */    
00495     void _sendCommand(uint8_t command); 
00496 
00497 /** @brief Write command that has one parameter
00498 */    
00499     void _sendCommand(uint8_t command, uint8_t param1);
00500 
00501 /** @brief Write command that has two parameters
00502 */ 
00503     void _sendCommand(uint8_t command, uint8_t param1, uint8_t param2);              
00504 //    void sendCommands(uint8_t len, uint8_t* buf);
00505 
00506 /** @brief Write command that has five parameters
00507 */ 
00508     void _sendCommand(uint8_t command, uint8_t param1, uint8_t param2,
00509                                        uint8_t param3, uint8_t param4,
00510                                        uint8_t param5);
00511 
00512 /** @brief Write command that has six parameters
00513 */ 
00514     void _sendCommand(uint8_t command, uint8_t param1, uint8_t param2,
00515                                        uint8_t param3, uint8_t param4,
00516                                        uint8_t param5, uint8_t param6);
00517     
00518 /** @brief Write databyte to display
00519  *  @brief Start at current cursor location
00520  *  @param uint8_t data databyte to write
00521 */  
00522     void _sendData(uint8_t data);
00523 
00524 /** @brief Write len bytes from buffer data to display, 
00525  *  @brief Start at current cursor location
00526  *  @param uint8_t len number of bytes to write 
00527  *  @param uint8_t* data pointer to data
00528 */   
00529     void _sendData(uint8_t len, uint8_t* data);
00530 
00531 /** @brief Low level Init
00532  *  @brief Init the configuration registers in accordance with the datasheet
00533  */   
00534     void _init();
00535 
00536     I2C _i2c;              // I2C bus reference
00537     uint8_t _readOpcode;   // contains the I2C address of the device
00538     uint8_t _writeOpcode;  // contains the I2C address of the device
00539     
00540     bool _inverted;        // inverted or normal text   
00541 };
00542 
00543 #endif