python-periphery 
Linux Peripheral I/O (GPIO, LED, PWM, SPI, I2C, MMIO, Serial) with Python 2 & 3
python-periphery is a pure Python library for GPIO, LED, PWM, SPI, I2C, MMIO, and Serial peripheral I/O interface access in userspace Linux. It is useful in embedded Linux environments (including Raspberry Pi, BeagleBone, etc. platforms) for interfacing with external peripherals. python-periphery is compatible with Python 2 and Python 3, is written in pure Python, and is MIT licensed.
Using Lua or C? Check out the lua-periphery and c-periphery projects.
Contributed libraries: java-periphery, dart_periphery
Installation
With pip:
`` text
pip install python-periphery
text
easy_install python-periphery
With easy_install:
text
git clone https://github.com/vsergeev/python-periphery.git
cd python-periphery
python setup.py install
With setup.py:## Examples
GPIO python
from periphery import GPIOOpen GPIO /dev/gpiochip0 line 10 with input direction
gpio_in = GPIO("/dev/gpiochip0", 10, "in")Open GPIO /dev/gpiochip0 line 12 with output direction
gpio_out = GPIO("/dev/gpiochip0", 12, "out")value = gpio_in.read() gpio_out.write(not value)
gpio_in.close() gpio_out.close()
Go to GPIO documentation.
LED
Open LED "led0" with initial state off
led0 = LED("led0", False)Open LED "led1" with initial state on
led1 = LED("led1", True)value = led0.read() led1.write(value)
Set custom brightness level
led1.write(led1.max_brightness / 2)led0.close() led1.close()
Go to LED documentation.
PWM
Open PWM chip 0, channel 10
pwm = PWM(0, 10)Set frequency to 1 kHz
pwm.frequency = 1e3Set duty cycle to 75%
pwm.duty_cycle = 0.75pwm.enable()
Change duty cycle to 50%
pwm.duty_cycle = 0.50pwm.close()
Go to PWM documentation.
SPI
Open spidev1.0 with mode 0 and max speed 1MHz
spi = SPI("/dev/spidev1.0", 0, 1000000)data_out = [0xaa, 0xbb, 0xcc, 0xdd] data_in = spi.transfer(data_out)
print("shifted out [0x{:02x}, 0x{:02x}, 0x{:02x}, 0x{:02x}]".format(*data_out)) print("shifted in [0x{:02x}, 0x{:02x}, 0x{:02x}, 0x{:02x}]".format(*data_in))
spi.close()
Go to SPI documentation.
I2C
Open i2c-0 controller
i2c = I2C("/dev/i2c-0")Read byte at address 0x100 of EEPROM at 0x50
msgs = [I2C.Message([0x01, 0x00]), I2C.Message([0x00], read=True)] i2c.transfer(0x50, msgs) print("0x100: 0x{:02x}".format(msgs[1].data[0]))i2c.close()
Go to I2C documentation.
MMIO
Open am335x real-time clock subsystem page
rtc_mmio = MMIO(0x44E3E000, 0x1000)Read current time
rtc_secs = rtc_mmio.read32(0x00) rtc_mins = rtc_mmio.read32(0x04) rtc_hrs = rtc_mmio.read32(0x08)print("hours: {:02x} minutes: {:02x} seconds: {:02x}".format(rtc_hrs, rtc_mins, rtc_secs))
rtc_mmio.close()
Open am335x control module page
ctrl_mmio = MMIO(0x44E10000, 0x1000)Read MAC address
mac_id0_lo = ctrl_mmio.read32(0x630) mac_id0_hi = ctrl_mmio.read32(0x634)print("MAC address: {:04x}{:08x}".format(mac_id0_lo, mac_id0_hi))
ctrl_mmio.close()
Go to MMIO documentation.
Serial
Open /dev/ttyUSB0 with baudrate 115200, and defaults of 8N1, no flow control
serial = Serial("/dev/ttyUSB0", 115200)serial.write(b"Hello World!")
Read up to 128 bytes with 500ms timeout
buf = serial.read(128, 0.5) print("read {:d} bytes: _{:s}_".format(len(buf), buf))serial.close()
Go to Serial documentation.
Documentation
Documentation is hosted at https://python-periphery.readthedocs.io.
To build documentation locally with Sphinx, run:
Sphinx will produce the HTML documentation in
docs/_build/html/.
Run
make help` to see other output targets (LaTeX, man, text, etc.).
Testing
The tests located in the tests folder may be run under Python to test the correctness and functionality of python-periphery. Some tests require interactive probing (e.g. with an oscilloscope), the installation of a physical loopback, or the existence of a particular device on a bus. See the usage of each test for more details on the required setup.
License
python-periphery is MIT licensed. See the included LICENSE file.