Revision 0:ee339d42b34d, committed 2020-01-02

Comitter:

bcsd69

Date:

Thu Jan 02 16:20:12 2020 +0000

Commit message:

Library for the I2C connected EA DOG204 LCD display. Version 1.00.000.

Changed in this revision

diff -r 000000000000 -r ee339d42b34d lcd_DOGM204_i2c.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lcd_DOGM204_i2c.cpp	Thu Jan 02 16:20:12 2020 +0000
@@ -0,0 +1,178 @@
+/** EA DOGM204 LCD class
+ *
+ * Provides access to the I2C connected Electronic Assembly DOGM204 LCD display
+ * with SSD1803A controller (www.lcd-module.de)
+ *
+ * Version: 1.00.000
+ * Date :   02.01.2020
+ * Author:  Marjan Hanc, www.m-hub.eu
+ *
+ * Note: This library does not support SPI and 4/8-Bit I/O modes of the display.
+ *      It is assumed, that the RS address selection pin is statically connected
+ *      either to the GND (SA=0) or VCC (SA=1).
+ **/
+
+#include "lcd_DOGM204_i2c.h"
+#include "mbed.h"
+
+/*\brief Initialises the LCD with respective I2C interface
+  \param sda        I2C SDA pin mapping
+  \param scl        I2C SCL pin mapping
+  \param SA         SA0 (selector) address of the LCD display
+  \param freq       Frequency of the I2C clock
+*/
+
+DOGM204I2C::DOGM204I2C(PinName sda, PinName scl, char SA, int frequency) : i2c(sda,scl) {
+
+     if (SA > 1)
+            error("DOGM204I2C: SA is out of range, must be 0..1\n");
+     else
+         _baseAdr = LCD_ADR + (SA << 1); // sets the base address of the LCD
+
+     if (frequency > Frequency_400KHz)
+         error("DOGM204I2C: I2C frequency out of range, must be less than 400 kHz\n");
+
+     i2c.frequency(frequency);
+}
+
+/*\brief Sends command with one data byte to the LCD
+  \param cmd        LCD command
+  \param dta        Data byte
+  \return status    Returns true, if the command was successful
+*/
+
+bool DOGM204I2C::lcd_i2c_write(char cmd, char dta)
+{
+    char data[] = {cmd, dta};
+
+    if (i2c.write(_baseAdr, data, 2)) {
+
+        return false;
+    }
+
+    return true;
+}
+
+/*\brief Reads one byte (command status) of the LCD
+  \param cmd        LCD command
+  \return data      Data byte
+*/
+
+char DOGM204I2C::lcd_i2c_read(char cmd)
+{
+    char data[] = {cmd};
+
+    i2c.write(_baseAdr, data, 1);    // note, that the base address occupies bits b1..b7
+    i2c.read(_baseAdr + 1, data, 1); // and that the b0 is R=1/W=0
+
+    return(data[0]);
+}
+
+/*\brief Writes single command to the LCD by checking the display status first
+  \note  The command is not fail safe. If the display doesn't return "not busy" it might hang forever
+  \param cmd    LCD command
+  \return stat  Returns true if successful
+*/
+
+bool DOGM204I2C::lcd_write_cmd(char data)
+{
+    //check and wait, if LCD is busy
+    while(lcd_i2c_read(LCD_STATUS) & LCD_BUSY);
+
+    // write command, control byte C0=0 & D/C = 0
+    return lcd_i2c_write(0x80, data);
+}
+
+/*\brief Writes data byte to the LCD by checking the display's busy flag BF first
+  \note  The command is not fail safe. If the display doesn't return "not busy" it might hang forever.
+  \param data   LCD data
+  \return stat  Returns true if successful
+*/
+bool DOGM204I2C::lcd_write_data(char data)
+{
+    //check and wait, if LCD is busy
+    while(lcd_i2c_read(LCD_STATUS) & LCD_BUSY);
+    //write data, control byte C0=0 & D/C = 1
+    return lcd_i2c_write(0x40, data);
+}
+
+// -- Public functions --
+
+/* \brief Sets the LCD display to the provided mode
+ * \param mode LCD_DISPLAY_ON|OFF LCD_CURSOR_ON|OFF LCD_BLINK_ON|OFF
+ */
+void DOGM204I2C::display_set(char mode)
+{
+    if (!lcd_write_cmd(0x08+mode))
+        error("DOGM204I2C: Write command in lcd_display_set() failed!\n");
+}
+
+/* \brief Sets the cursor to the given position counted from the origin
+ * \param pos  position
+ */
+void DOGM204I2C::set_pos(char pos)
+{
+    if (!lcd_write_cmd(LCD_HOME+pos))
+        error("DOGM204I2C: Write command in lcd_set_pos() failed!\n");
+}
+
+/* \brief Writes a single character at given position in the given line
+ * \param pos LCD_LINEx+position
+ */
+void DOGM204I2C::write_char(char line, char pos, char ch)
+{
+    char lcdpos = pos + 0x20 * line;
+
+    if (!lcd_write_cmd(lcdpos))
+        error("DOGM204I2C: Write command in lcd_write_char() failed!\n");
+    else
+        if (!lcd_write_data(ch))
+            error("DOGM204I2C: Write data in lcd_write_char() failed!\n");
+}
+
+/* \brief Writes null terminated string to the LCD
+ * \param s Null terminated string
+ */
+void DOGM204I2C::write(char *s)
+{
+    while(*s)
+    {
+        if (!lcd_write_data(*s++)) {
+            error("DOGM204I2C: Write data in lcd_write() failed!\n");
+            break;
+        }
+    }
+}
+
+/* \brief Clears the LCD display and sets the cursor to the top-left position
+ */
+void DOGM204I2C::cls()
+{
+    lcd_write_cmd(LCD_CLEAR);   // Clear display
+    lcd_write_cmd(LCD_RTHOME);  // Set cursor position to home (top left)
+}
+
+/* \brief Initializes LCD display
+ * \note  This sequence will set 4 lines, 5 dots, and top orientation at maximum 
+    contrast with cursor off
+ */
+void DOGM204I2C::init()
+{
+    lcd_write_cmd(0x3A);        // 8-Bit data length, extension Bit RE=1; REV=0
+    lcd_write_cmd(LCD_4LINE_MODE | LCD_FONT_5DOT ); // 4 lines, 5 dots charset
+
+    lcd_write_cmd(0x80);        // Pixel shift 0
+
+    lcd_write_cmd(LCD_TOPVIEW); // Set LCD orientation
+    lcd_write_cmd(0x1E);        // Bias setting BS1=1
+
+    lcd_write_cmd(0x39);        // 8-Bit data length extension Bit RE=0; IS=1
+    lcd_write_cmd(0x1B);        // BS0=1 -> Bias=1/6
+
+    lcd_write_cmd(0x6E);        // Divider ON and set value
+    lcd_write_cmd(0x57);        // Booster ON and set contrast (BB1=C5, DB0=C4)
+    lcd_write_cmd(0x7B);        // Set optimum contrast (DB3-DB0=C3-C0)
+
+    lcd_write_cmd(0x38);        // 8-Bit data length extension Bit RE=0; IS=0
+}
+

diff -r 000000000000 -r ee339d42b34d lcd_DOGM204_i2c.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lcd_DOGM204_i2c.h	Thu Jan 02 16:20:12 2020 +0000
@@ -0,0 +1,96 @@
+/** EA DOGM204 LCD header file
+ *
+ * Provides access to the I2C connected Electronic Assembly DOGM204 LCD display
+ * with SSD1803A controller (www.lcd-module.de)
+ *
+ * Version: 1.00.000
+ * Date :   02.01.2020
+ * Author:  Marjan Hanc, www.m-hub.eu
+ *
+ * Note: This library does not support SPI and 4/8-Bit I/O modes of display.
+ *      It is assumed, that the RS address selection pin is statically connected
+ *      either to the GND (SA0=0) or VCC (SA0=1).
+ **/
+
+#ifndef MBED_LCD_DOGM204
+#define MBED_LCD_DOGM204
+
+#include "mbed.h"
+
+class DOGM204I2C {
+
+    public:
+
+        enum LCD_Commands {
+            LCD_ADR    = 0x78,  // SA0=0, 0x7A when SA0=1
+            LCD_CLEAR  = 0x00,  // Clear Display
+            LCD_RTHOME = 0x02   // Return home
+        };
+
+        enum LCD_Status {
+            LCD_STATUS = 0x00,
+            LCD_DATA   = 0x40,
+            LCD_BUSY   = 0x80
+        };
+
+        enum LCD_Charset {
+            LCD_ROMA = 0x00,
+            LCD_ROMB = 0x04,
+            LCD_ROMC = 0x0C
+        };
+
+        enum LCD_Mode {
+            LCD_CURSOR_LINE  = 0x00,
+            LCD_CURSOR_BLOCK = 0x02,
+            LCD_TOPVIEW      = 0x05,
+            LCD_BOTVIEW      = 0x06,
+            LCD_2LINE_MODE   = 0x08, // Base setting for 1 & 2 line mode
+            LCD_4LINE_MODE   = 0x09, // Base setting for 3 & 4 line mode
+            LCD_FONT_5DOT    = 0x00,
+            LCD_FONT_6DOT    = 0x04
+        };
+
+        enum LCD_Settings {
+            LCD_DISPLAY_ON  = 0x04,
+            LCD_DISPLAY_OFF = 0x03,
+            LCD_CURSOR_ON   = 0x02,
+            LCD_CURSOR_OFF  = 0x05,
+            LCD_BLINK_ON    = 0x01,
+            LCD_BLINK_OFF   = 0x06
+        };
+
+        enum LCD_Positions {
+            LCD_HOME  = 0x80,
+            LCD_LINE1 = 0x00,
+            LCD_LINE2 = 0x20,
+            LCD_LINE3 = 0x40,
+            LCD_LINE4 = 0x60
+        };
+
+        enum Frequency {
+            Frequency_100KHz = 100000,
+            Frequency_400KHz = 400000
+        };
+
+        DOGM204I2C(PinName sda, PinName scl, char SA, int frequency);
+
+        void display_set(char mode);
+        void set_pos(char pos);
+        void write_char(char line, char pos, char ch);
+        void write(char *s);
+        void cls();
+        void init();
+
+    private:
+        char _baseAdr;  // LCD base address (0x78 or 0x7A, depends on SA0)
+
+        I2C  i2c;  // I2C interface
+
+        bool lcd_i2c_write(char cmd, char dta);
+        char lcd_i2c_read(char cmd);
+        bool lcd_write_cmd(char data);
+        bool lcd_write_data(char data);
+};
+
+
+#endif