PLEASE NOTE: This library may have breaking changes as development continues. Please read the changelog anytime you update the library!

The PWM Duty Cycle range was reversed in 0.0.15 from 100(off)-0(on) to 0(off)-100(on). Please update your code accordingly.

Adafruit's BeagleBone IO Python Library

This is a set of Python tools to allow GPIO, PWM, and ADC access on the BeagleBone using the Linux 3.8 Kernel and above (latest releases).

It has been tested on the 5-20 and 6-6 Angstrom image on the BeagleBone Black.

Note: BBIO has been renamed to Adafruit_BBIO.

Installation on Angstrom

Easiest:

/usr/bin/ntpdate -b -s -u pool.ntp.org
opkg update && opkg install python-pip python-setuptools
pip install Adafruit_BBIO

Manual:

git clone git://github.com/adafruit/adafruit-beaglebone-io-python.git
#set the date and time
/usr/bin/ntpdate -b -s -u pool.ntp.org
#install dependency
opkg update && opkg install python-distutils
cd adafruit-beaglebone-io-python
python setup.py install

Installation on Ubuntu/Debian

Easiest:

sudo ntpdate pool.ntp.org
sudo apt-get update
sudo apt-get install build-essential python-dev python-pip -y
#easy_install -U distribute  //debian only
sudo pip install Adafruit_BBIO

Manual:

sudo ntpdate pool.ntp.org
sudo apt-get update
sudo apt-get install build-essential python-dev python-pip -y
git clone git://github.com/adafruit/adafruit-beaglebone-io-python.git
cd adafruit-beaglebone-io-python
sudo python setup.py install
cd ..
sudo rm -rf adafruit-beaglebone-io-python

Usage

Using the library is very similar to the excellent RPi.GPIO library used on the Raspberry Pi. Below are some examples.

GPIO Setup

Import the library, and setup as GPIO.OUT or GPIO.IN:

import Adafruit_BBIO.GPIO as GPIO
GPIO.setup("P8_14", GPIO.OUT)

You can also refer to the pin names:

GPIO.setup("GPIO0_26", GPIO.OUT)

GPIO Output

Setup the pin for output, and write GPIO.HIGH or GPIO.LOW. Or you can use 1 or 0.:

import Adafruit_BBIO.GPIO as GPIO
GPIO.setup("P8_14", GPIO.OUT) GPIO.output("P8_14", GPIO.HIGH)

On-Board LEDs

On-board LEDs (USR0-USR3) are handled by LED class driver rather than the GPIO pin driver.

They have a different path in the /sys/ filesystem.

Setup the pin for output and write GPIO.HIGH or GPIO.LOW:

import Adafruit_BBIO.GPIO as GPIO
import time

for i in range(4):
    GPIO.setup("USR%d" % i, GPIO.OUT)

while True:
    for i in range(4):
        GPIO.output("USR%d" % i, GPIO.HIGH)
        time.sleep(1)
    for i in range(4):
        GPIO.output("USR%d" % i, GPIO.LOW)
        time.sleep(1)

GPIO Input

Inputs work similarly to outputs.:

import Adafruit_BBIO.GPIO as GPIO
GPIO.setup("P8_14", GPIO.IN)

Polling inputs:

if GPIO.input("P8_14"):
  print("HIGH")
else:
  print("LOW")

Waiting for an edge (GPIO.RISING, GPIO.FALLING, or GPIO.BOTH:

GPIO.wait_for_edge(channel, GPIO.RISING)

or

GPIO.wait_for_edge(channel, GPIO.RISING, timeout)

Detecting events:

GPIO.add_event_detect("P9_12", GPIO.FALLING)
#your amazing code here
#detect wherever:
if GPIO.event_detected("P9_12"):
  print "event detected!"

PWM:

import Adafruit_BBIO.PWM as PWM
#PWM.start(channel, duty, freq=2000, polarity=0)
#duty values are valid 0 (off) to 100 (on)
PWM.start("P9_14", 50)
PWM.set_duty_cycle("P9_14", 25.5)
PWM.set_frequency("P9_14", 10)

PWM.stop("P9_14")
PWM.cleanup()

#set polarity to 1 on start:
PWM.start("P9_14", 50, 2000, 1)

ADC:

import Adafruit_BBIO.ADC as ADC
ADC.setup()

#read returns values 0-1.0
value = ADC.read("P9_40")

#read_raw returns non-normalized value
value = ADC.read_raw("P9_40")

Running tests

Install py.test to run the tests. You'll also need the python compiler package for py.test.:

opkg update && opkg install python-compiler
#Either pip or easy_install
pip install -U pytest
easy_install -U pytest

Execute the following in the root of the project:

py.test

Credits

The BeagleBone IO Python library was originally forked from the excellent MIT Licensed [RPi.GPIO](https://code.google.com/p/raspberry-gpio-python) library written by Ben Croston.

License

Written by Justin Cooper, Adafruit Industries. BeagleBone IO Python library is released under the MIT License.