Stefan Staub / mbedLCDi2c
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LCD HD44780 library with I2C adapter for Mbed 6


Download repository: zip

mbed6 LCDi2c library for HD47780

This library is for the HD47780 LCDs with I2C interface for use with mbed 6

Installation

  1. “Download”:https://github.com/sstaub/mbedLCDi2c/archive/master.zip the Master branch from GitHub.
  2. Unzip and modify the folder name to “mbedLCDi2c”
  3. Move the modified folder on your Library folder.

Example

Here is a simple example which shows the capabilities of the display

// example for mbed6 LCD library

#include "mbed.h"
#include "LCDi2c.h"

// special chars
uint8_t upArrow[8] = {  
    0b00100,
    0b01010,
    0b10001,
    0b00100,
    0b00100,
    0b00100,
    0b00000,
    };

uint8_t downArrow[8] = {
    0b00000,
    0b00100,
    0b00100,
    0b00100,
    0b10001,
    0b01010,
    0b00100,
    };

uint8_t rightArrow[8] = {
    0b00000,
    0b00100,
    0b00010,
    0b11001,
    0b00010,
    0b00100,
    0b00000,
    };

uint8_t leftArrow[8] = {
    0b00000,
    0b00100,
    0b01000,
    0b10011,
    0b01000,
    0b00100,
    0b00000,
    };

//LCD_I2C lcd(I2C_SDA, I2C_SCL, LCD16x2, 0x27); // SDA, SCL, device address, LCD type
LCDi2c lcd(I2C_SDA, I2C_SCL);

int main() {

    lcd.create(0, downArrow);
    lcd.create(1, upArrow);
    lcd.create(2, rightArrow);
    lcd.create(3, leftArrow);

    lcd.cls();
    lcd.locate(0, 0);
    lcd.printf("Hello World!\n");
    lcd.character(0, 1, 0);
    lcd.character(3, 1, 1);
    lcd.character(5, 1, 2);
    lcd.character(7, 1, 3);

    ThisThread::sleep_for(2s);
    lcd.cls();
    lcd.locate(0, 0);
    lcd.printf("Hello World!\n");

    ThisThread::sleep_for(2s);
    lcd.display(BACKLIGHT_OFF);
    ThisThread::sleep_for(2s);
    lcd.display(BACKLIGHT_ON);
    ThisThread::sleep_for(2s);
    lcd.display(DISPLAY_OFF);
    ThisThread::sleep_for(2s);
    lcd.display(DISPLAY_ON);
    ThisThread::sleep_for(2s);
    lcd.display(CURSOR_ON);
    ThisThread::sleep_for(2s);
    lcd.display(BLINK_ON);
    ThisThread::sleep_for(2s);
    lcd.display(BLINK_OFF);
    ThisThread::sleep_for(2s);
    lcd.display(CURSOR_OFF);

    while(1) {
        for (uint8_t pos = 0; pos < 13; pos++) {
        // scroll one position to left
        lcd.display(SCROLL_LEFT);
        // step time
        ThisThread::sleep_for(500ms);
        }

    // scroll 29 positions (string length + display length) to the right
    // to move it offscreen right
    for (uint8_t pos = 0; pos < 29; pos++) {
      // scroll one position to right
      lcd.display(SCROLL_RIGHT);
      // step time
      ThisThread::sleep_for(500ms);
        }

    // scroll 16 positions (display length + string length) to the left
    // to move it back to center
    for (uint8_t pos = 0; pos < 16; pos++) {
      // scroll one position to left
      lcd.display(SCROLL_LEFT);
      // step time
      ThisThread::sleep_for(500ms);
        }

        ThisThread::sleep_for(1s);
        }
    }

Documentation

Display types

following display types are supported

  • LCD16x2 16x2 LCD panel (default)
  • LCD20x2 20x2 LCD panel
  • LCD20x4 20x4 LCD panel
  • LCD40x2 40x2 LCD panel

Constructor

create a LCD object

LCDi2c::LCDi2c(PinName sda, PinName scl, lcd_t type = LCD16x2, int deviceAddress = 0x27);
LCDi2c::LCDi2c(lcd_t type, int deviceAddress = 0x27);
  • sda I2C SDA pin
  • scl I2C SCL pin
  • deviceAddress I2C device address
  • type display type

Example

LCDi2c lcd(I2C_SDA, I2C_SCL);
LCDi2c lcd(LCD16x2); // using standard I2C pins I2C_SDA, I2C_SCL

Class Functions

Clear Screen

void LCDi2c::cls()

clears the screen, set cursor to home

Example

lcd.cls();

Display Modes

void LCDi2c::display(modes_t mode)

set the modes of the display

  • DISPLAY_ON turn the display on
  • DISPLAY_OFF turn the display off
  • CURSOR_ON turn the underline cursor on
  • CURSOR_OFF turn the underline cursor off
  • BLINK_ON turn the blinking cursor on
  • BLINK_OFF turn the blinking cursor off
  • SCROLL_LEFT these command scroll the display without changing the RAM
  • SCROLL_RIGHT these command scroll the display without changing the RAM
  • LEFT_TO_RIGHT this is for text that flows Left to Right
  • RIGHT_TO_LEFT this is for text that flows Right to Left
  • AUTOSCROLL_ON this will ‘right justify’ text from the cursor
  • AUTOSCROLL_OFF this will ‘left justify’ text from the cursor
  • BACKLIGHT_ON turn the backlight on
  • BACKLIGHT_OFF turn the backlight off

Example

lcd.display(CURSOR_ON);

Cursor Location

void LCDi2c::locate(uint8_t column, uint8_t row)

set poition of the cursor

  • column position column
  • row position row

Example

lcd.locate(0, 0);

Cursor Home

void LCDi2c::home()

set cursor to home position (0/0)

Example

lcd.home();

User defined chars

void LCDi2c::create(uint8_t location, uint8_t charmap[])

Create a user defined char object allows us to fill the first 8 CGRAM locations with custom characters

  • loacation number 0 - 7
  • charmap array which contains the char

Example

uint8_t upArrow[8] = {  
    0b00100,
    0b01010,
    0b10001,
    0b00100,
    0b00100,
    0b00100,
    0b00000,
    };

lcd.create(0, downArrow);

Character

void LCDi2c::character(uint8_t column, uint8_t row, uint8_t c)

draw a single character on given position, usefull for user chars

  • column position column
  • row position row
  • c number of the user char

Example

lcd.character(0, 1, 0);

Helper Function

I2C address parser

void parseI2C()

Is a helper function for scanning the I2C address of the device if is unknown.

Example

parseI2C();