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.