Using a character LCD display with PyBoard:

A project including circuit and Python Module!

This project includes a python module with heavily commented code, meant for hobbyists to use and modify, as well as a Fritzing circuit diagram and photograph of the end result. This should allow you to attach a character display screen to your PyBoard very easily.

Required:

• Pyboard 1.1 with micro-SD card
• Standard sized breadboard
• Wires
• Mini breadboard-mount potentiometer
• Some knowledge of Python.

CHAR_LCD.py

CHAR_LCD.py is a module for micropython (meant for the PyBoard v1.0 or 1.1) meant to allow easy use of LCD character displays of the standard parallel-in type (viz, Hitachi HD44780 or compatible character display chipsets).

The code for this project has been released under the MIT License.

Tested on PyBoard v1.1 running micropython. (http://www.micropython.org)

TESTED LCDs:

• Generic 16x2 green character display
• Adafruit standard 20x4 blue character LCD

Compatibility:

• Any LCD chipset compatible with the Hitachi HDD44780

This module should give you a pretty self-contained set of functions for writing text to a character LCD display of the standard 8-bit-parallel input kind.

This is a library of functions. Not a class. It would be unnecessary to make this a class, and would complexify the usage for hobbyists.

This library ASSUMES you are using PyBoard pins X1-X8 to communicate to the LCD display.

Requires: pyb module; stm module.

###Features Implemented:

• CLEAR / RESET the display
• multiple sizes (e.g. 16x2 or 20x4)
• user specified command & latch pins
• change to command mode or input mode
• LOCATE cursor anywhere on the screen.
• WRITE an ASCII character
• WRITE a string
• WRITE a full line of text

###Not Implemented:

• Scrolling
• Changing the text viewport in memory
• Custom LCD characters
• Serial in / out from character display
• READ from character display

FURTHER READING:

• 'How to Use Intelligent L.C.D.s' by Julyan Ilett, "Constructional Feature".
• (http://lcd-linux.sourceforge.net/pdfdocs/lcd1.pdf)
• Datasheet: LCM Module TC2004A-01
• (https://cdn-shop.adafruit.com/datasheets/TC2004A-01.pdf)

###KNOWN ISSUES:

• (Minor) clear_display() and reset_display() do not show consistent behavior for all displays.
• (Minor) Sometimes you must call reset_display() twice (in a row) to get the desired behavior.

For more information read the code comments.

The code for CHAR_LCD.py is pretty heavily commented because this project is meant for hobbyists just starting out with PyBoard!