https://github.com/fangfufu/adafruit-rpi-lcd

A C program/library to drive Adafruit's RGB LCD Pi Plate
https://github.com/fangfufu/adafruit-rpi-lcd

Last synced: 3 months ago
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A C program/library to drive Adafruit's RGB LCD Pi Plate

• Host: GitHub
• URL: https://github.com/fangfufu/adafruit-rpi-lcd
• Owner: fangfufu
• License: gpl-3.0
• Created: 2013-08-20T03:07:22.000Z (about 12 years ago)
• Default Branch: master
• Last Pushed: 2013-12-30T12:28:33.000Z (almost 12 years ago)
• Last Synced: 2025-04-12T02:21:27.486Z (6 months ago)
• Language: C
• Homepage:
• Size: 344 KB
• Stars: 5
• Watchers: 2
• Forks: 3
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

          
Adafruit-RPi-LCD

=============================================

@mainpage

Documentation

-------------

You can generate a nice set of html documentation by issuing the following

command:

    doxygen Doxyfile

Introduction

------------

This program allows you to control Adafruit Raspberry Pi 

RGB LCD Plate.

This project started off as a C library for driving the Adafruit Raspberry Pi 

RGB LCD Plate. It should work for the monochrome version with minor 

modification.

The original idea was that you include the header file in your project, so you 

can drive the LCD very easily. You can even do a "printf" to the LCD. I don't

think many libraries have such nice feature. This library also perform

proper error checking.

If you don't have Doxygen, and you are on Debian-based system, you can install

Doxygen by issuing:

    sudo apt-get install doxygen

Installation

------------

You can install the program by issuing the following commands:

    make

    sudo make install

Please note that the compilation stage can be done on a Debian machine if you 

have installed gcc-4.7-arm-linux-gnueabi from the Emdebian repository.

If you have Raspberry Pi Revision 1, you should replace the 'make' with:

    make RPI_REV1=1

Uninstallation

--------------

To uninstall type in the following in your terminal:

    sudo make uninstall

Dependency

----------

This library/program depends on kernel module i2c-dev. You can load the module

by typing in:

    modprobe i2c-dev

Alternatively you can edit /etc/modules.

Usage

-----

    Adafruit-RPi-LCD v1.00, Adafruit Raspberry Pi LCD Plate Controller

    Usage: adafruit-rpi-lcd [OPTION]... [MESSAGE]...

    -c, --colour                  Set LCD colour, possible colour include:

                                    Black, Red, Yellow, Green, Cyan, Blue, 

                                    Magenta, White.

                                    Colour names are case insensitive.

    -u, --cursor                  Set LCD cursor, possible option include:

                                    On, Off, Blink

                                    Cursor options are case insensitive.

    -v, --verbose                 Turn on the verbose mode

    -h, --help                    Print this help message

    Report bugs and make suggestions at:

    https://github.com/fangfufu/Adafruit-RPi-LCD/issues

Example

-------

To output the current time on your LCD, type in the following: 

    date +\ \ \ %d\ %b\ %_Y\ \ \ \ \ \ %H:%M\ %Z | /usr/local/bin/adafruit-rpi-lcd -c yellow

You can use your LCD as a clock by putting this in your crontab, and run it

once every minute.

Exit Code

---------

Below is a table of the exit code for adafruit-rpi-lcd:

 Exit Code | Description

-----------|--------------------------------------------

    0      | Successfully printed a message.

    1      | Printed the help message in the terminal.

    2      | Colour option was invalid.

    3      | Cursor option was invalid.

    5      | Colour option and Cursor option were both invalid.

Header files

------------

Here is a brief description of what each header file do:

* gpio.h: functions related to the I2C GPIO expander

* button.h: functions related to GPIO buttons

* lcd.h: functions related to the normal operation of the LCD.

* lcd_cgram.h: functions for creating custom characters on the LCD.

* lcd_lowlevel.h: low level LCD functions, you should never need to included

this header.

Initialisation

--------------

To initialise the LCD plate, you need to include gpio.h and lcd.h. You can

initialise the system by calling the following functions:

    GPIO_open() // Open the GPIO ports for read/write operations.

    LCD_init() // Initialise the LCD and perform self-check.

Additional Information

----------------------

### Links

#### Vendors

You can buy the LCD plate from the following places:

* Adafruit:

http://www.adafruit.com/products/1110

* UK Distributor (I bought mine there):

https://www.modmypi.com/raspberry-pi-RGB-negative-16x2-LCD-kit

#### Datasheets

Hopefully my code is clear enough so you don't need datasheets. But if you care

about how it all works, here is the additional information.

* MCP23017 I2C I/O expander:

http://ww1.microchip.com/downloads/en/devicedoc/21952b.pdf

* HD44780 LCD Controller (ROM Code A00):

https://www.adafruit.com/datasheets/HD44780.pdf

#### Other resources

* Adafruit's code for the Python LCD Plate:

https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code/blob/master/Adafruit_CharLCDPlate/Adafruit_CharLCDPlate.py

### Pin Table

The MCP23017 I2C I/O expander has two 8-bit GPIO ports. I have included the

pin connection table below for reference:

Pin No. |7       |6       |5       |4       |3       |2       |1       |0

--------|--------|--------|--------|--------|--------|--------|--------|-------

 GPIO A:|GREEN   |RED     |        |LEFT    |UP      |DOWN    |RIGHT   |SELECT

 GPIO B:|RS      |R/!W    |E       |DB4     |DB5     |DB6     |DB7     |BLUE