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Adafruit_BBIO 1.0.9

A module to control BeagleBone IO channels

# Adafruit BeagleBone I/O Python Library (Adafruit_BBIO)

* Adafruit_BBIO is a set of Python tools to allow [GPIO](, [PWM](, [ADC]( and [UART]( access on the BeagleBone

* It is recommended to use an [official Debian image](
* **Currently recommended image: [Debian 9.2 "Stretch" iot (2017-10-29)](**
* Install [Linux kernel]( [4.14.x]( to enable [non-root control of GPIO]( and [PWM]( [_(commit)_](

* Adafruit_BBIO supports Linux kernels 3.8 through 4.14

* New versions of Adafruit_BBIO may break backwards compatibility. Please read the [changelog](

## Installation on Debian

sudo ntpdate
sudo apt-get update
sudo apt-get install build-essential python-dev python-pip -y
sudo pip install Adafruit_BBIO

sudo ntpdate
sudo apt-get update
sudo apt-get install build-essential python-dev python-pip -y
git clone git://
cd adafruit-beaglebone-io-python
sudo python install

Upgrade Adafruit_BBIO to latest version on [PyPI](
sudo pip install --upgrade Adafruit_BBIO

## Usage

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

### Pin Numbers

Please note that there is no '0' prefix for the pin numbers. For example, pin 7 on header P8 is `P8_7`.

GPIO.setup("P8_7", OUT )

GPIO.setup("P8_07", OUT )

Refer to `pins_t table[]` in [common.c]( all the pin labels.

### config-pin

[config-pin]( is now used on the official Debian Jessie and Stretch images to control pin mode (e.g. pin mux).

debian@beaglebone:~$ config-pin -q P9_14
P9_14 Mode: pwm

debian@beaglebone:~$ config-pin -l P9_14
default gpio gpio_pu gpio_pd pwm

debian@beaglebone:~$ config-pin P9_14 gpio

debian@beaglebone:~$ config-pin -q P9_14
P9_14 Mode: gpio Direction: in Value: 0

debian@beaglebone:~$ config-pin P9_14 pwm

debian@beaglebone:~$ config-pin -q P9_14
P9_14 Mode: pwm

### 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)
for i in range(4):
GPIO.output("USR%d" % i, GPIO.LOW)

### 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"):

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

GPIO.wait_for_edge(channel, GPIO.RISING)


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
**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.**

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)


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

### ADC

import Adafruit_BBIO.ADC as ADC

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

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

### [UART](
* Use [`config-pin` to set pin mode]( for [UART1 and UART2 pins](
config-pin P9.21 uart # UART2_TXD
config-pin P9.22 uart # UART2_RXD
config-pin P9.24 uart # UART1_TXD
config-pin P9.26 uart # UART1_RXD
* [Install pyserial](
sudo pip install pyserial
* [Test UART1](
import Adafruit_BBIO.UART as UART
import serial


ser = serial.Serial(port = "/dev/ttyO1", baudrate=9600)
if ser.isOpen():
print "Serial is open!"
ser.write("Hello World!")
* [Loopback test with UART1 and UART2](

## Running tests

Install py.test to run the tests. You'll also need the python compiler package for pytest:
sudo pip install pytest
Execute the following in the root of the project:
sudo pytest
NOTE: `sudo` should not be required when running [Debian 9.2 "Stretch" iot (2017-10-29)]( with [Linux kernel]( [4.14.x]( as udev configures group ownership and permission for [GPIO]( and [PWM](

## Credits

The BeagleBone IO Python library was originally forked from the excellent MIT Licensed [RPi.GPIO]( library written by Ben Croston.

## License

Written by Justin Cooper, Adafruit Industries. BeagleBone IO Python library is released under the MIT License.
* Issue #194: Encoder position cannot be set
* PR #205: Encoder: add support for reading/writing sysfs attributes

* Issue #198: use https for DEFAULT_URL in
* Issue #197: Fix leak of pwm enable file descriptor
* Issue #189: Fix seg fault of PWM in Python 3.6
* Issue #180: Clarify there is no 0 prefix for pin lables
* PR #201: Encoder: do kernel check, PEP8 cleanup
* PR #202: Encoder: corrected kernel check logic
* PR #207: Encoder: improved usage documentation
* PR #210: Encoder: fix sysfs import, make code Python 3 compatible
* PR #212: Encoder: fix Python 3 compatibility
* PR #213: Encoder: fix frequency calculation from period

* David Planella (18):
* Encoder: initialize only the given channel
* Sync from master
* Encoder: do kernel check, PEP8 cleanup
* Encoder: added sysfs module
* Encoder: use sysfs to write QEP attributes
* Encoder: corrected kernel check logic
* Merge pull request #2 from adafruit/master
* Encoder: convert get/set methods to properties, update apidoc strings
* Encoder: updated README
* Encoder: add README apt install clarification
* Encoder: copyright assignment note, updated comments
* Encoder: added usage notes
* Encoder: improved usage documentation
* Encoder: minor fix to usage example
* Encoder: added a note about permissions
* Encoder: switched sysfs to be a relative import compatible with Python 2 and 3
* Encoder: use items() instead of iteritems() to be Python 3 compatible
* Encoder: fix frequency getter

* Drew Fustini (18):
* use https for DEFAULT_URL in (#198)
* fix except syntax for Python 3
* use dict.items() instead of dict.iteritems() for Python 3
* fix error in set_brightness()
* close enable_fd when stopping PWM output (#197)
* Merge pull request #199 from dplanella/patch-1
* Fix leak of pwm enable file descriptor (#197)
* Merge pull request #201 from dplanella/encoder-cleanup
* remove as not valid for pytest
* Fix seg fault of PWM in Python 3.6 (#189)
* Merge pull request #202 from dplanella/patch-2
* Clarify there is no 0 prefix for pin lables (#180)
* Merge pull request #205 from dplanella/encoder-sysfs
* assign copyright for new file to Adafruit Industries
* Add bash scripts to help install and test
* Merge pull request #212 from dplanella/patch-4
* Merge pull request #207 from dplanella/patch-3
* Merge pull request #213 from dplanella/fix-encoder-frequency

* Issue #196: cache board type to avoid poor performance
* Issue #192: fix PocketBeagle PWM pin typo
* Issue #191: turn off RotaryEncoder's debug output by default
* Issue #188: GPIO is extremely slow (20ms to toggle)
* Issue #186: problems with UART

* David Planella (12):
* Copy Encoder module comments to
* Formatted Encoder README in markdown
* Fixed Encoder README formatting
* Removed QEP instructions from Encoder module
* Fixes to Encoder README
* Updated Encoder README
* Encoder README: added info on dedicated overlays
* Encoder README: updated info on pre-requisites
* Encoder README update
* Encoder README update
* Add logging support, turn off unconditional debug output
* Encoder: remove unused logging code

* Drew Fustini (3):
* Merge pull request #195 from dplanella/master
* Fix PocketBeagle PWM pin typo (#192)
* cache board type to avoid poor performance (#196)

* Issue #188: GPIO is extremely slow (20ms to toggle)

* Drew Fustini (4):
* Update
* add config-pin example to README
* Filter DEBUG syslog to avoid poor performance #188
* Change log level from INFO to DEBUG #188

* Currently recommended image: [Debian 9.2 "Stretch" iot (2017-10-29)](
* Install [Linux kernel]( [4.14.x]( to enable [non-root control of GPIO]( and [PWM]( [_(commit)_](

* Add support for Linux 4.14 kernel including new "udev" style for PWM entries in /sys
* Fix GPIO regression due to BeagleBone Blue LED support (issue #178)
* Add support for the PocketBeagle (issue #172)

* Drew Fustini (39):
* Add -Wno-unit_address_vs_reg to avoid dtc warning
* check if board is BeagleBone Blue or PocketBeagle
* check if BeagleBone Blue before accessing non-standard LEDs
* Add test for GPIO regression #178
* change syslog mask level to DEBUG
* add "Adafruit_BBIO" to syslog()
* update test for issue #178
* remove polarity "hack" for PWM #170
* move pwm_set_polarity() after period is set
* add test for issue #170
* only check kernel overlays if u-boot overlays are not being used
* Attempt to use udev ecap path for pwm path
* add test script for all BeagleBone PWM outputs
* update PWM test for 4.14 kernel udev paths
* minor change to pwm debug logging
* sleep to avoid udev race condition #185

* Mark A. Yoder (1):
* Added BAT25, BAT50, BAT75, BAT100 and WIFI LEDs

* Peter Lawler (1):
* Missing CR/LF

* Robert Nelson (10):
* source/common.c: add initial PocketBeagle values
* source/common.c: PocketBeagle, no slots file, everything built-in
* source/common.c: PocketBeagle, no slots file disable here too
* source/c_pwm.c: HACK: U-Boot pre-setup everything, dont search for specific overlay
* source/c_pwm.c: HACK: PocketBeagle: v4.14.x
* source/c_pwm.c: debug pwm_path/pwm_path_udev
* source/c_pwm.c: pwm: add support for pwmchipX/pwm-X:Y syntax
* source/c_pwm.c: disable pwm_set_polarity (broken in v4.9.x/v4.14.x)
* source/common.c: Blue Fix GP0_3 id
* source/common.c: PocketBeagle Fix P2.24

* @pdp7 (5):
* Merge pull request #153 from MarkAYoder/master
* Fix print syntax to avoid python3 errors
* Merge pull request #160 from MarkAYoder/master
* document how to read QEP1
* Update

* @MarkAYoder (20):
* Have GP0_1 working
* Removed --force to speed things up
* Added GP0 1, 2 and 3
* Flashes 4 LEDs
* Works with button
* Blinks red and gree LEDs
* Blinks all 6 GPIOs
* Added red and green LEDs
* i2c works
* PWD isn't working, yet
* Added port setup
* Switched to apt install
* Added tmp101 to name
* Added LED matrix example
* Removed newline from print
* Added fade
* Adding GPIO defs for uart1
* Testing UT1_0, not working yet
* Switched GP0_0 to GP0_3, etc.
* Added PAUSE and MODE buttons.

* @djsutton (1):
* fix TypeError: function takes exactly 3 arguments (2 given) from wait_for_edge

* @pdp7 (29):
* Instruct users to open GitHub issue instead email
* add udev rules and script for non-root access to gpio
* fix file descriptor leak in gpio_set_value()
* document how to test read and write to all GPIO pins
* reduce ADC reads in pytest from 10,000 to 1,000
* close file descriptor to avoid leak
* remove conditional logic for ctrl_dir and ocp_dir size
* increase size of ctrl_dir and ocp_dir for future use
* Document how to run config-pin at boot
* Document how to test eQEP with Rotary Encoder
* Add skeleton for Encoder module to read eQEP
* Add code to Encoder.QEP from PyBBIO.RotaryEncoder
* Adapt code from PyBBIO.RotaryEncoder
* add test for rotary encoder
* read from eqep position file
* return position from getPosition()
* document howo to enable all the eqep pins
* Document how to test eqep pins with rotary encoder
* run config-pin to set pin mux for qep
* update QEP test
* update QEP test for issue #122
* Test if kernel booted wit u-boot overlays
* check if kernel cmdline for uboot overlay
* Add documentation about u-boot overlays
* Return BBIO_OK when u-boot overlays ared enabled
* remove debug printing
* Skip check for device tree loaded if u-boot overlays enabled
* Sleep after loading ADC overlay to allow driver load
* Workaround test failure until TIMERn bug is fixed

* @ltjax (3):
* Use lookup table to prevent duplicate pin export
* Handle already exported pins
* Fix build_path memory leak

* @Vadim-Stupakov (1):
* Fixed issue #145 GPIO library doesn't free GPIO file descriptor. File descriptor leak. Made a little bit refactoring

* @cocasema (8):
* Declare PHONY targets in root Makefile
* Extract BBIO_err into a separate header
* Add syslog and debugging messages
* Add libadafruit-bbio with C++ wrappers for PWM/GPIO
* Add 2 versions of library with c++98 and c++11 abi
* Install header files properly
* Add default values to pwm::start() method.
* Add PWM c++ tests

* @zsserg (2):
* Added error checking for setting pin direction in gpio.setup() (Python)
* Added debug output to set_pin_mode()

* Add -Wno-strict-aliasing to CFLAGS to ignore gcc warning
* Resolves GitHub issue #133 by @archey

* Merge pull request #130 from adafruit/issue129-usr-leds [1439133]
* Add support for alternate USR LED labels
* Merge pull request #131 from adafruit/fix-gcc-warnings [f0ee018]
* Fix gcc warnings
* Merge pull request #132 from buckket/setup_unicode_fix [4c67dfc]
* Make use of with explicit file encoding in

* Merge pull request #124 from jpbarraca/master [cf9771a]
* Timeout support for wait_for_edge (replaces PR #62)
* Merge pull request #123 from bubbapizza/master [8b4f7f2]
* Added a delay parameter for GPIO.setup() for udev permissions
* Merge pull request #121 from dengber/master [50e8883]
* returns wrong value
* Merge pull request #64 from olegantonyan/master [d1e8dc1]
* Wait until GPIO file appears on the /sys filesystem (issue #36)
* Merge pull request #106 from cocasema/master [12b79d7]
* Treat warnings as errors
* Merge pull request #119 from JesseMcL/pr [e7e987a]
* Add GPIO pullup configurations and fix PWM Segfault on kernel 4.1+
* Merge pull request #116 from kozga/master [1b04cdf]
* Fix SPI: IOError: [Errno 22] Invalid argument in xfer and xfer2 funct…

* Merge pull request #108 from MatthewWest for PWM support in Linux kernel 4.1+
* Merge pull request #96 from PeteLawler for ADC support in Linux kernel 4.1+
* Finally publish new version to PyPi
* Bump major version number to signify long duration since last release

* Merge Python 3 compatibility fixes from Github user westphahl.
* Moved old Angstrom build fix for missing py_compile from to separate file.

* Fix for SPI not loading spidevX.X correctly based on load order
* Initialize ctrl_dir in unload_device_tree #63
* Clean up unused/dead code

* Fix for SPI.xfer crashes python after 3 calls
* Added a retry to reading for the analog inputs to avoid a bug where reading back and forth between two analog inputs would cause the resource to be unavailable every 16 scans (zthorson)
* Updated the build_path to be more selective over what paths it chooses (zthorson)
* Update Debian installation instructions in README (justinledwards)
* Increase the size of the buffer used for storing device tree names (SaintGimp)

* UART - Include UART overlays, and compile upon installation
* UART - Rename UART overlays
* Adafruit_I2C - Remove readU16Rev and readS16Rev
* Adafruit_I2C - Updated readU16/readS16 for correct 16-bit reads

* Fix SPI memory leaks
* Clean up of PWM code (bit-hacker, jwcooper)
* Remove UART debug statements

* Add polarity as optional fourth parameter to PWM.start(). Valid values are 0 and 1. Default is still 0.
* Fix for actually setting the polarity in start.
* Add new unit tests to check that the polarity is being set properly, and valid values passed in.

* Fix PWM duty cycle so 0 is off and 100 is on. Set polarity to 0 by default.
* Give extra buffer space in export, and unexport functions for gpio that are more than 2 digits (Chris Desjardins)
* Add new test case for 3 digit gpio (Chris Desjardins)
* Fix for test_direction_readback. gpio_get_direction wasn't properly null terminating the direction string (Chris Desjardins)

* Fix GPIO.gpio_function to work with the IO name (zthorson)
* Fix IOErrors not getting raised when fopen fails while loading overlays into device tree (bradfordboyle, jwcooper)
* Add new UART tests

* Remove the gpio parameter from callbacks (cdesjardins)

* Bump version due to pypi issues

* New UART module to export UART overlays
* Alpha support for SPI
* Add small delay after loading any device tree overlays

* Fix direction for event detection code
* Fix for segmentation faults on add_event_detect

* Fix for ADC Segmentation Faults

* Temp remove overlay compilation. Ubuntu failures.

* Refactor and clean up adc and pwm
* Fix tests for Adafruit_BBIO rename

* Include as top-level module

* Rename from BBIO to Adafruit_BBIO to reduce library conflicts and confusion.

* Support for pip and easy_install

* ADC enabled

* PWM enabled

* Initial Commit
* GPIO mostly working
* Initial GPIO unit tests
* PWM in progress  
File Type Py Version Uploaded on Size
Adafruit_BBIO-1.0.9.tar.gz (md5) Source 2017-12-01 62KB