RPLCD

A Python 3/2 Raspberry PI Character LCD library for the Hitachi HD44780 controller. It supports both GPIO (parallel) mode as well as boards with an I2C port expander (e.g. the PCF8574).

This library is inspired by Adafruit Industries' CharLCD library as well as by Arduino's LiquidCrystal library.

No external dependencies (except the RPi.GPIO library, which comes preinstalled on Raspbian) are needed to use this library.

Setup

You can install RPLCD directly from PyPI using pip:

$ sudo pip install RPLCD

If you want to use I2C, you also need smbus:

$ sudo apt install python-smbus

You can also install the library manually without pip. Either just copy the scripts to your working directory and import them, or download the repository and run python setup.py install to install it into your Python package directory.

Features

Implemented

• Simple to use API
• Support for both 4 bit and 8 bit modes
• Support for both parallel and I²C connection
• Support for custom characters
• Support for backlight control circuits
• Python 2/3 compatible
• Caching: Only write characters if they changed
• No external dependencies (except RPi.GPIO)

Wishlist

These things may get implemented in the future, depending on my free time and motivation:

• MicroPython port

Documentation

You can find the documentation here: https://readthedocs.org/projects/rplcd/

Testing

Test Scripts

To test your 20x4 display, please run the test_20x4.py script and confirm/verify each step with the enter key. If you don't use the standard wiring, make sure to add your pin numbers to the CharLCD constructor in test_20x4.py.

To test a 16x2 display, proceed as explained above, but use the test_16x2.py script instead.

Unit Tests

There are also unit tests. First, install dependencies:

pip install -U -r requirements-dev.txt

Then run the tests:

py.test -v

Coding Guidelines

PEP8 via flake8 with max-line-width set to 99 and E126-E128,C901 ignored:

flake8 --max-line-length=99 --ignore=E126,E127,E128,C901 RPLCD/lcd.py

Resources

• TC2004A-01 Data Sheet: http://www.adafruit.com/datasheets/TC2004A-01.pdf
• HD44780U Data Sheet: http://www.adafruit.com/datasheets/HD44780.pdf

License

This code is licensed under the MIT license, see the LICENSE file or tldrlegal for more information.

The module RPLCD/enum.py is (c) 2004-2013 by Barry Warsaw. It was distributed as part of the flufl.enum package under the LGPL License version 3 or later.