/**
@mainpage libpifacedigital - A simple C library for PiFace Digital.

[pifacedigital.h](pifacedigital_8h.html)

@section links Links

- [piface.org.uk](http://www.piface.org.uk)
- [PiFace product source code](http://piface.github.io)
- [Source code on GitHub](https://github.com/piface/libpifacedigital)
- [libmcp23s17](http://piface.github.io/libmcp23s17)

@section use Using the library

Download:

    $ git clone https://github.com/piface/libmcp23s17.git
    $ git clone https://github.com/piface/libpifacedigital.git

Build the library:

    $ cd libmcp23s17/ && make && cd -
    $ cd libpifacedigital/ && make

This creates the library `libpifacedigital.a`.

Build and run the example and the pifacedigital utility for command line
control:

    $ make example
    $ ./example

    $ make pifacedigital
    $ ./pifacedigital read input
    $ ./pifacedigital --help

Include the library in your project with:

    $ gcc -o example example.c -Isrc/ -L. -lpifacedigital -L../libmcp23s17/ -lmcp23s17

`-I` directories to search for header files.
`-L` directories to search for libraries.
`-l` libraries to link.

@section todo Todo

Feel free to contribute!

- mcp23s17_fd checking for each function. Print to stderr if not found.
- Debian install

*/