esp32-i2c-lcd1602-example

Introduction

This is an example application for the HD4470-compatible LCD1602 device connected via an I2C backpack.

This application is also usable with an LCD2004 module (20 columns, 4 rows), by uncommenting the LCD_NUM_ROWS, LCD_NUM_COLUMNS, and LCD_NUM_VISIBLE_COLUMNS definitions at the top of app_main.c.

It is written and tested for v3.3 of the ESP-IDF environment, using the xtensa-esp32-elf toolchain (gcc version 5.2.0).

Ensure that submodules are cloned:

$ git clone --recursive https://github.com/DavidAntliff/esp32-i2c-lcd1602-example.git

Build the application with:

$ cd esp32-i2c-lcd1602-example.git
$ idf.py menuconfig    # set your serial configuration and the I2C GPIO - see below
$ idf.py build
$ idf.py -p (PORT) flash monitor

The program should detect your connected device and display some demonstration text on the LCD.

Dependencies

This application makes use of the following components (included as submodules):

• components/esp32-smbus
• components/esp32-i2c-lcd1602

Hardware

To run this example, connect one LCD1602 device to two GPIOs on the ESP32 (I2C SDA and SCL). If external pull-up resistors are not provided with the sensor, add a 10 KOhm resistor from each GPIO to the 3.3V supply.

idf.py menuconfig can be used to set the I2C GPIOs and LCD1602 device I2C address.

Note that the 3.3V supply may be insufficient to run the display satisfactorily. In this case I suggest using a 5V supply to the LCD display, and using appropriate level shifter circuitry on the I2C SCL and SDA connections.

Features

This example steps through the features of the esp32-i2c-lcd1602 component. It demonstrates:

• Display initialisation, disabling and enabling, clearing.
• Backlight control.
• Underline and blinking cursor control, including arbitrary cursor movement and homing.
• Display scrolling.
• Custom character definition.
• Display of all characters.

Each step waits for a keypress on stdin before executing. If stdin is not available (no USB/UART available), modify the following code:

//#define USE_STDIN  1
#undef USE_STDIN

Each step will then wait for one second before proceeding automatically.

Source Code

The source is available from GitHub.

License

The code in this project is licensed under the MIT license - see LICENSE for details.

Links

• HD44780 Dot Matrix Liquid Crystal Display Controller/Driver datasheet
• Espressif IoT Development Framework for ESP32

Acknowledgements

• "I2C" is a registered trademark of Phillips Corporation.
• "SMBus" is a trademark of Intel Corporation.