Port of the Arduino library with the same library. Includes a instance of the Print library from arduino
Summary
A Conversion of the Arduino LiquidCrystal_I2C by Frank de Brabander to MBED
Version of original Library: 1.1.2
Information from the original library: The library allows to control I2C displays with functions extremely similar to LiquidCrystal library.
Original Github: https://github.com/johnrickman/LiquidCrystal_I2C
Code Example
This is a working example using the basic library features
example.cpp
#include "LiquidCrystal_I2C.h" LiquidCrystal_I2C lcd(0x27, 20, 4, I2C_SDA, I2C_SCL); void setup(); void loop(); //Arduino style setup function void setup() { lcd.init(); for (int i = 0; i < 3; i++) { lcd.backlight(); wait_ms(250); lcd.noBacklight(); wait_ms(250); } lcd.backlight(); lcd.setCursor(3, 0); // Start at character 4 on line 0 lcd.print("Hello, world!"); wait_ms(500); lcd.setCursor(2, 1); lcd.print("From YourDuino"); wait_ms(500); lcd.setCursor(0, 2); lcd.print("20 by 4 Line Display"); lcd.setCursor(1, 3); wait_ms(1000); lcd.print("DVSProductions.de"); wait_ms(8000); } //print some random characters void loop() { //lcd.setCursor(rand() % 20, rand() % 4); //lcd.print(rand() % 10); for (int x = 0; x != 20; x++) for (int y = 0; y != 20; y++) lcd.print(rand() % 10); } //Behave like an Arduino int main() { setup(); while (true)loop(); }
Misc
It is important to note that the library requires the init function to be called before sending any data. Instead of the arduino typical:
arduino.ino
LiquidCrystal_I2C lcd(0x27, 20, 4); void setup(){ lcd.begin(20, 4); }
We pass the pins and size to the constructor and then just call the init function:
mbed.cpp
LiquidCrystal_I2C lcd(0x27, 20, 4, I2C_SDA, I2C_SCL); void setup(){ lcd.init(); }
Also important is that the begin function still has value. It is now able to change the size of the LCD after the constructor. This might have few applications, but it is more powerful than the Arduino version, where the parameters had barely any use.
LiquidCrystal_I2C.cpp
- Committer:
- DVSProductions
- Date:
- 2019-08-15
- Revision:
- 4:402a5c6b2457
- Parent:
- 3:9c8694d5744a
File content as of revision 4:402a5c6b2457:
// Based on the work by DFRobot upgraded by DVSProductions #include "LiquidCrystal_I2C.h" #include <inttypes.h> /*********** mid level commands, for sending data/cmds */ #define COMMAND(value) send(value, 0) #define printIIC(args) i2c->write(_Addr, args, 1) size_t LiquidCrystal_I2C::write(uint8_t value) { send(value, Rs); return 1; } inline void LiquidCrystal_I2C::command(uint8_t value) { send(value, 0); } // When the display powers up, it is configured as follows: // // 1. Display clear // 2. Function set: // DL = 1; 8-bit interface data // N = 0; 1-line display // F = 0; 5x8 dot character font // 3. Display on/off control: // D = 0; Display off // C = 0; Cursor off // B = 0; Blinking off // 4. Entry mode set: // I/D = 1; Increment by 1 // S = 0; No shift // // Note, however, that resetting the Arduino doesn't reset the LCD, so we // can't assume that its in that state when a sketch starts (and the // LiquidCrystal constructor is called). /*! Creates a new LCD instance !*/ LiquidCrystal_I2C::LiquidCrystal_I2C(uint8_t lcd_Addr, uint8_t lcd_cols, uint8_t lcd_rows, PinName sda, PinName scl) { _Addr = lcd_Addr << 1; _cols = lcd_cols; _rows = lcd_rows; _backlightval = LCD_NOBACKLIGHT; i2c = new I2C(sda, scl); i2c->frequency(1000000); } void LiquidCrystal_I2C::init() { init_priv(); } void LiquidCrystal_I2C::init_priv() { _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS; begin_priv(); } void LiquidCrystal_I2C::begin_priv(uint8_t dotsize) { if (_rows > 1) { _displayfunction |= LCD_2LINE; } _numlines = _rows; // for some 1 line displays you can select a 10 pixel high font if ((dotsize != 0) && (_rows == 1)) { _displayfunction |= LCD_5x10DOTS; } // SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION! // according to datasheet, we need at least 40ms after power rises above 2.7V // before sending commands. Nucleo can turn on way befer 4.5V so we'll wait // 50 wait_ms(50); // Now we pull both RS and R/W low to begin commands expanderWrite(_backlightval); // reset expanderand turn backlight off (Bit 8 =1) wait_ms(1000); // put the LCD into 4 bit mode // this is according to the hitachi HD44780 datasheet // figure 24, pg 46 // we start in 8bit mode, try to set 4 bit mode write4bits(0x03 << 4); wait_us(4100); // wait min 4.1ms // second try write4bits(0x03 << 4); wait_us(4100); // wait min 4.1ms // third go! write4bits(0x03 << 4); wait_us(150); // finally, set to 4-bit interface write4bits(0x02 << 4); // set # lines, font size, etc. COMMAND(LCD_FUNCTIONSET | _displayfunction); // turn the display on with no cursor or blinking default _displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF; display(); // clear it off clear(); // Initialize to default text direction (for roman languages) _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT; // set the entry mode COMMAND(LCD_ENTRYMODESET | LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT); home(); } void LiquidCrystal_I2C::begin(uint8_t cols, uint8_t lines, uint8_t dotsize) { _cols = cols; _rows = lines; begin_priv(); } /********** high level commands, for the user! */ void LiquidCrystal_I2C::clear() { COMMAND(LCD_CLEARDISPLAY); // clear display, set cursor position to zero wait_us(2000); // this command takes a long time! } void LiquidCrystal_I2C::home() { COMMAND(LCD_RETURNHOME); // set cursor position to zero wait_us(2000); // this command takes a long time! } void LiquidCrystal_I2C::setCursor(uint8_t col, uint8_t row) { int row_offsets[] = { 0x00, 0x40, 0x14, 0x54 }; if (row > _numlines) row = _numlines - 1; // we count rows starting w/0 COMMAND(LCD_SETDDRAMADDR | (col + row_offsets[row])); } // Turn the display on/off (quickly) void LiquidCrystal_I2C::noDisplay() { _displaycontrol &= ~LCD_DISPLAYON; COMMAND(LCD_DISPLAYCONTROL | _displaycontrol); } void LiquidCrystal_I2C::display() { _displaycontrol |= LCD_DISPLAYON; COMMAND(LCD_DISPLAYCONTROL | _displaycontrol); } // Turns the underline cursor on/off void LiquidCrystal_I2C::noCursor() { _displaycontrol &= ~LCD_CURSORON; COMMAND(LCD_DISPLAYCONTROL | _displaycontrol); } void LiquidCrystal_I2C::cursor() { _displaycontrol |= LCD_CURSORON; COMMAND(LCD_DISPLAYCONTROL | _displaycontrol); } // Turn on and off the blinking cursor void LiquidCrystal_I2C::noBlink() { _displaycontrol &= ~LCD_BLINKON; COMMAND(LCD_DISPLAYCONTROL | _displaycontrol); } void LiquidCrystal_I2C::blink() { _displaycontrol |= LCD_BLINKON; COMMAND(LCD_DISPLAYCONTROL | _displaycontrol); } // These commands scroll the display without changing the RAM void LiquidCrystal_I2C::scrollDisplayLeft(void) { COMMAND(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT); } void LiquidCrystal_I2C::scrollDisplayRight(void) { COMMAND(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT); } // This is for text that flows Left to Right void LiquidCrystal_I2C::leftToRight(void) { _displaymode |= LCD_ENTRYLEFT; COMMAND(LCD_ENTRYMODESET | _displaymode); } // This is for text that flows Right to Left void LiquidCrystal_I2C::rightToLeft(void) { _displaymode &= ~LCD_ENTRYLEFT; COMMAND(LCD_ENTRYMODESET | _displaymode); } // This will 'right justify' text from the cursor void LiquidCrystal_I2C::autoscroll(void) { _displaymode |= LCD_ENTRYSHIFTINCREMENT; COMMAND(LCD_ENTRYMODESET | _displaymode); } // This will 'left justify' text from the cursor void LiquidCrystal_I2C::noAutoscroll(void) { _displaymode &= ~LCD_ENTRYSHIFTINCREMENT; COMMAND(LCD_ENTRYMODESET | _displaymode); } // Allows us to fill the first 8 CGRAM locations // with custom characters void LiquidCrystal_I2C::createChar(uint8_t location, uint8_t charmap[]) { location &= 0x7; // we only have 8 locations 0-7 COMMAND(LCD_SETCGRAMADDR | (location << 3)); for (uint8_t i = 0; i != 8; i++) write(charmap[i]); } // Turn the (optional) backlight off/on void LiquidCrystal_I2C::noBacklight(void) { _backlightval = LCD_NOBACKLIGHT; expanderWrite(0); } void LiquidCrystal_I2C::backlight(void) { _backlightval = LCD_BACKLIGHT; expanderWrite(0); } /************ low level data pushing commands **********/ // write either command or data void LiquidCrystal_I2C::send(uint8_t value, uint8_t mode) { uint8_t highnib = value & 0xf0; uint8_t lownib = (value << 4) & 0xf0; write4bits((highnib) | mode); write4bits((lownib) | mode); } void LiquidCrystal_I2C::write4bits(uint8_t value) { expanderWrite(value); pulseEnable(value); } char buff; inline void LiquidCrystal_I2C::expanderWrite(uint8_t _data) { buff = (_data) | _backlightval; printIIC(&buff); } void LiquidCrystal_I2C::pulseEnable(uint8_t _data) { expanderWrite(_data | En); // En high wait_us(1); // enable pulse must be >450ns expanderWrite(_data & ~En); // En low wait_us(10); // commands need > 37us to settle } // Alias functions inline void LiquidCrystal_I2C::cursor_on() { cursor(); } inline void LiquidCrystal_I2C::cursor_off() { noCursor(); } inline void LiquidCrystal_I2C::blink_on() { blink(); } inline void LiquidCrystal_I2C::blink_off() { noBlink(); } inline void LiquidCrystal_I2C::load_custom_character(uint8_t char_num, uint8_t *rows) { createChar(char_num, rows); } void LiquidCrystal_I2C::setBacklight(uint8_t new_val) { if (new_val) backlight(); // turn backlight on else noBacklight(); // turn backlight off } void LiquidCrystal_I2C::printstr(const char c[]) { // This function is not identical to the function used for "real" I2C displays // it's here so the use sketch doesn't have to be changed print(c); } // unsupported API functions void LiquidCrystal_I2C::off() { noBacklight(); } void LiquidCrystal_I2C::on() { begin_priv(); backlight(); } void LiquidCrystal_I2C::setDelay(int cmdDelay, int charDelay) {} uint8_t LiquidCrystal_I2C::status() { return 0; } uint8_t LiquidCrystal_I2C::keypad() { return 0; } uint8_t LiquidCrystal_I2C::init_bargraph(uint8_t graphtype) { return 0; } void LiquidCrystal_I2C::draw_horizontal_graph(uint8_t row, uint8_t column, uint8_t len, uint8_t pixel_col_end) { } void LiquidCrystal_I2C::draw_vertical_graph(uint8_t row, uint8_t column, uint8_t len, uint8_t pixel_row_end) { } void LiquidCrystal_I2C::setContrast(uint8_t new_val) {}