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# python-periphery [](https://app.travis-ci.com/github/vsergeev/python-periphery) [](https://python-periphery.readthedocs.io/en/latest/) [](https://github.com/vsergeev/python-periphery) [](https://github.com/vsergeev/python-periphery/blob/master/LICENSE)
## 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](https://github.com/vsergeev/lua-periphery) and [c-periphery](https://github.com/vsergeev/c-periphery) projects.
Contributed libraries: [java-periphery](https://github.com/sgjava/java-periphery), [dart_periphery](https://github.com/pezi/dart_periphery)
## Installation
With pip:
``` text
pip install python-periphery
```
With easy_install:
``` text
easy_install python-periphery
```
With setup.py:
``` text
git clone https://github.com/vsergeev/python-periphery.git
cd python-periphery
python setup.py install
```
## Examples
### GPIO
``` python
from periphery import GPIO
# Open 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.](https://python-periphery.readthedocs.io/en/latest/gpio.html)
### LED
``` python
from periphery import 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.](https://python-periphery.readthedocs.io/en/latest/led.html)
### PWM
``` python
from periphery import PWM
# Open PWM chip 0, channel 10
pwm = PWM(0, 10)
# Set frequency to 1 kHz
pwm.frequency = 1e3
# Set duty cycle to 75%
pwm.duty_cycle = 0.75
pwm.enable()
# Change duty cycle to 50%
pwm.duty_cycle = 0.50
pwm.close()
```
[Go to PWM documentation.](https://python-periphery.readthedocs.io/en/latest/pwm.html)
### SPI
``` python
from periphery import 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.](https://python-periphery.readthedocs.io/en/latest/spi.html)
### I2C
``` python
from periphery import 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.](https://python-periphery.readthedocs.io/en/latest/i2c.html)
### MMIO
``` python
from periphery import 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.](https://python-periphery.readthedocs.io/en/latest/mmio.html)
### Serial
``` python
from periphery import 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.](https://python-periphery.readthedocs.io/en/latest/serial.html)
## Documentation
Documentation is hosted at [https://python-periphery.readthedocs.io](https://python-periphery.readthedocs.io).
To build documentation locally with Sphinx, run:
```
cd docs
make html
```
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](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](LICENSE) file.
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