lcd_DOGM204_i2c.cpp

00001 /** EA DOGM204 LCD class
00002  *
00003  * Provides access to the I2C connected Electronic Assembly DOGM204 LCD display
00004  * with SSD1803A controller (www.lcd-module.de)
00005  *
00006  * Version: 1.00.000
00007  * Date :   02.01.2020
00008  * Author:  Marjan Hanc, www.m-hub.eu
00009  *
00010  * Note: This library does not support SPI and 4/8-Bit I/O modes of the display.
00011  *      It is assumed, that the RS address selection pin is statically connected
00012  *      either to the GND (SA=0) or VCC (SA=1).
00013  **/
00014 
00015 #include "lcd_DOGM204_i2c.h"
00016 #include "mbed.h"
00017 
00018 /*\brief Initialises the LCD with respective I2C interface
00019   \param sda        I2C SDA pin mapping
00020   \param scl        I2C SCL pin mapping
00021   \param SA         SA0 (selector) address of the LCD display
00022   \param freq       Frequency of the I2C clock
00023 */
00024 
00025 DOGM204I2C::DOGM204I2C(PinName sda, PinName scl, char SA, int frequency) : i2c(sda,scl) {
00026 
00027      if (SA > 1)
00028             error("DOGM204I2C: SA is out of range, must be 0..1\n");
00029      else
00030          _baseAdr = LCD_ADR + (SA << 1); // sets the base address of the LCD
00031 
00032      if (frequency > Frequency_400KHz)
00033          error("DOGM204I2C: I2C frequency out of range, must be less than 400 kHz\n");
00034 
00035      i2c.frequency(frequency);
00036 }
00037 
00038 /*\brief Sends command with one data byte to the LCD
00039   \param cmd        LCD command
00040   \param dta        Data byte
00041   \return status    Returns true, if the command was successful
00042 */
00043 
00044 bool DOGM204I2C::lcd_i2c_write(char cmd, char dta)
00045 {
00046     char data[] = {cmd, dta};
00047 
00048     if (i2c.write(_baseAdr, data, 2)) {
00049 
00050         return false;
00051     }
00052 
00053     return true;
00054 }
00055 
00056 /*\brief Reads one byte (command status) of the LCD
00057   \param cmd        LCD command
00058   \return data      Data byte
00059 */
00060 
00061 char DOGM204I2C::lcd_i2c_read(char cmd)
00062 {
00063     char data[] = {cmd};
00064 
00065     i2c.write(_baseAdr, data, 1);    // note, that the base address occupies bits b1..b7
00066     i2c.read(_baseAdr + 1, data, 1); // and that the b0 is R=1/W=0
00067 
00068     return(data[0]);
00069 }
00070 
00071 /*\brief Writes single command to the LCD by checking the display status first
00072   \note  The command is not fail safe. If the display doesn't return "not busy" it might hang forever
00073   \param cmd    LCD command
00074   \return stat  Returns true if successful
00075 */
00076 
00077 bool DOGM204I2C::lcd_write_cmd(char data)
00078 {
00079     //check and wait, if LCD is busy
00080     while(lcd_i2c_read(LCD_STATUS) & LCD_BUSY);
00081 
00082     // write command, control byte C0=0 & D/C = 0
00083     return lcd_i2c_write(0x80, data);
00084 }
00085 
00086 /*\brief Writes data byte to the LCD by checking the display's busy flag BF first
00087   \note  The command is not fail safe. If the display doesn't return "not busy" it might hang forever.
00088   \param data   LCD data
00089   \return stat  Returns true if successful
00090 */
00091 bool DOGM204I2C::lcd_write_data(char data)
00092 {
00093     //check and wait, if LCD is busy
00094     while(lcd_i2c_read(LCD_STATUS) & LCD_BUSY);
00095     //write data, control byte C0=0 & D/C = 1
00096     return lcd_i2c_write(0x40, data);
00097 }
00098 
00099 // -- Public functions --
00100 
00101 /* \brief Sets the LCD display to the provided mode
00102  * \param mode LCD_DISPLAY_ON|OFF LCD_CURSOR_ON|OFF LCD_BLINK_ON|OFF
00103  */
00104 void DOGM204I2C::display_set(char mode)
00105 {
00106     if (!lcd_write_cmd(0x08+mode))
00107         error("DOGM204I2C: Write command in lcd_display_set() failed!\n");
00108 }
00109 
00110 /* \brief Sets the cursor to the given position counted from the origin
00111  * \param pos  position
00112  */
00113 void DOGM204I2C::set_pos(char pos)
00114 {
00115     if (!lcd_write_cmd(LCD_HOME+pos))
00116         error("DOGM204I2C: Write command in lcd_set_pos() failed!\n");
00117 }
00118 
00119 /* \brief Writes a single character at given position in the given line
00120  * \param pos LCD_LINEx+position
00121  */
00122 void DOGM204I2C::write_char(char line, char pos, char ch)
00123 {
00124     char lcdpos = pos + 0x20 * line;
00125 
00126     if (!lcd_write_cmd(lcdpos))
00127         error("DOGM204I2C: Write command in lcd_write_char() failed!\n");
00128     else
00129         if (!lcd_write_data(ch))
00130             error("DOGM204I2C: Write data in lcd_write_char() failed!\n");
00131 }
00132 
00133 /* \brief Writes null terminated string to the LCD
00134  * \param s Null terminated string
00135  */
00136 void DOGM204I2C::write(char *s)
00137 {
00138     while(*s)
00139     {
00140         if (!lcd_write_data(*s++)) {
00141             error("DOGM204I2C: Write data in lcd_write() failed!\n");
00142             break;
00143         }
00144     }
00145 }
00146 
00147 /* \brief Clears the LCD display and sets the cursor to the top-left position
00148  */
00149 void DOGM204I2C::cls()
00150 {
00151     lcd_write_cmd(LCD_CLEAR);   // Clear display
00152     lcd_write_cmd(LCD_RTHOME);  // Set cursor position to home (top left)
00153 }
00154 
00155 /* \brief Initializes LCD display
00156  * \note  This sequence will set 4 lines, 5 dots, and top orientation at maximum 
00157     contrast with cursor off
00158  */
00159 void DOGM204I2C::init()
00160 {
00161     lcd_write_cmd(0x3A);        // 8-Bit data length, extension Bit RE=1; REV=0
00162     lcd_write_cmd(LCD_4LINE_MODE | LCD_FONT_5DOT ); // 4 lines, 5 dots charset
00163 
00164     lcd_write_cmd(0x80);        // Pixel shift 0
00165 
00166     lcd_write_cmd(LCD_TOPVIEW); // Set LCD orientation
00167     lcd_write_cmd(0x1E);        // Bias setting BS1=1
00168 
00169     lcd_write_cmd(0x39);        // 8-Bit data length extension Bit RE=0; IS=1
00170     lcd_write_cmd(0x1B);        // BS0=1 -> Bias=1/6
00171 
00172     lcd_write_cmd(0x6E);        // Divider ON and set value
00173     lcd_write_cmd(0x57);        // Booster ON and set contrast (BB1=C5, DB0=C4)
00174     lcd_write_cmd(0x7B);        // Set optimum contrast (DB3-DB0=C3-C0)
00175 
00176     lcd_write_cmd(0x38);        // 8-Bit data length extension Bit RE=0; IS=0
00177 }
00178