************************************************************************
PyBBIO - v0.3
Created: 12/2011
Author: Alexander Hiam - [email protected] - www.alexanderhiam.com
Website: https://github.com/alexanderhiam/PyBBIO

A Python library for hardware IO support on the TI Beaglebone.

Copyright (c) 2012 - Alexander Hiam 

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
************************************************************************

The goal of this library is to create a simple programming environment 
similar to the Arduino. At the moment it supports basic digital IO
through digitalRead() and digitalWrite() functions, as well as ADC
support through analogRead(). PWM and UART are on the way, so keep 
checking the Github page for updates.  

I am using the same pin names as are assigned to the BeagleBone's two
female expansion headers in the schematic, which can be found here:
  http://beagleboard.org/hardware/design/

Full API documentation found here:
  http://www.alexanderhiam.com/code/pybbio/

The python-mmap module is required and was not installed on my BeagleBone,
despite it usually being part of the standard Python modules. 
It can easily be installed by running at the BeagleBone shell:
  # opkg update; opkg install python-mmap

Installing PyBBIO:
 -With GIT:
   Requirements: 
    -BeagleBone connected to the internet.
    -BeagleBone shell access, either through serial port or ssh.   
   1. On BeagleBone, cd to the location you want to download PyBBIO in, e.g.:
        # cd ~
   2. Clone the git repository:
        # git clone git://github.com/alexanderhiam/PyBBIO.git
   3. Run installer:
        # cd PyBBIO/
        # sh install.sh -i
   4. Test PyBBIO:
        # cd examples/
        # python blink.py
      If all is well you should see two of the LEDs next to the Ethernet jack
      blinking back and forth. Press CTRL-C to stop.

 -Without GIT:
   Requirements: 
    -BeagleBone shell access, either through serial port or ssh.   
   1. Download PyBBBIO from:
        https://github.com/alexanderhiam/PyBBIO/downloads
   2. Unpack PyBBIO directory and cp onto BeagleBone. The simplest way
      to do this is just to remove the microSD card from the board (not while
      it's on!), pop it in a card reader and mount it on your computer. It
      should mount as two seperate filesystems; open the one called 
      Angstrom-Cloud9- and copy PyBBIO/ to home/root/. Then unmount the card
      and place it back in the BeagleBone.
   Complete steps 3 and 4 above.

Uninstalling PyBBIO:
  1. On BeagleBone, cd into PyBBIO folder, e.g.:
       # cd ~/PyBBIO
  2. Run installer with uninstall flag:
       # sh install.sh -u
  PyBBIO configuration directory and Python module will be removed,
  3. PyBBIO folder can then be deleted, e.g.:
       # cd ..
       # rm -rf PyBBIO
  
Note:
 If you've installed PyBBIO with 'git clone' and then update it with 
 'git pull', you'll have to run 'sh install -i' again for the changes to
 take effect. 


Hardware access is acheived using a memory map of the special file /dev/mem, 
which is a map of the entire physical memory of the AM3358 ARM processor. 
The addresses of all the processor's memory registers, as well as details
on how to properly use them, can be found in the AM335x Technical Reference 
Manual (TI document spruh73c.pdf) which can be found here:
  http://www.ti.com/dsp/docs/dspsupporttechdocs.tsp?sectionId=3&tabId=409&docCategoryId=6&viewType=mostuseful&rootFamilyId=44&familyId=2920
Direct link:
 http://www.ti.com/litv/pdf/spruhd7