160 lines
5.4 KiB
Python
160 lines
5.4 KiB
Python
# Copyright (c) 2014 Adafruit Industries
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# Author: Tony DiCola
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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import platform
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OUT = 0
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IN = 1
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HIGH = True
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LOW = False
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class BaseGPIO(object):
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"""Base class for implementing simple digital IO for a platform.
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Implementors are expected to subclass from this and provide an implementation
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of the setup, output, and input functions."""
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def setup(self, pin, mode):
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"""Set the input or output mode for a specified pin. Mode should be
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either OUT or IN."""
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raise NotImplementedError
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def output(self, pin, value):
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"""Set the specified pin the provided high/low value. Value should be
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either HIGH/LOW or a boolean (true = high)."""
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raise NotImplementedError
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def input(self, pin):
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"""Read the specified pin and return HIGH/true if the pin is pulled high,
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or LOW/false if pulled low."""
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raise NotImplementedError
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def set_high(self, pin):
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"""Set the specified pin HIGH."""
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self.output(pin, HIGH)
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def set_low(self, pin):
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"""Set the specified pin LOW."""
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self.output(pin, LOW)
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def is_high(self, pin):
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"""Return true if the specified pin is pulled high."""
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return self.input(pin) == HIGH
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def is_low(self, pin):
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"""Return true if the specified pin is pulled low."""
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return self.input(pin) == LOW
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class RPiGPIOAdapter(BaseGPIO):
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"""GPIO implementation for the Raspberry Pi using the RPi.GPIO library."""
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def __init__(self, rpi_gpio, mode=None):
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self.rpi_gpio = rpi_gpio
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# Suppress warnings about GPIO in use.
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rpi_gpio.setwarnings(False)
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if mode == rpi_gpio.BOARD or mode == rpi_gpio.BCM:
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rpi_gpio.setmode(mode)
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elif mode is not None:
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raise ValueError('Unexpected value for mode. Must be BOARD or BCM.')
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else:
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# Default to BCM numbering if not told otherwise.
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rpi_gpio.setmode(rpi_gpio.BCM)
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def setup(self, pin, mode):
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"""Set the input or output mode for a specified pin. Mode should be
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either OUTPUT or INPUT.
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"""
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self.rpi_gpio.setup(pin, self.rpi_gpio.IN if mode == IN else \
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self.rpi_gpio.OUT)
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def output(self, pin, value):
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"""Set the specified pin the provided high/low value. Value should be
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either HIGH/LOW or a boolean (true = high).
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"""
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self.rpi_gpio.output(pin, value)
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def input(self, pin):
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"""Read the specified pin and return HIGH/true if the pin is pulled high,
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or LOW/false if pulled low.
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"""
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return self.rpi_gpio.input(pin)
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class AdafruitBBIOAdapter(BaseGPIO):
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"""GPIO implementation for the Beaglebone Black using the Adafruit_BBIO
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library.
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"""
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def __init__(self, bbio_gpio):
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self.bbio_gpio = bbio_gpio
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def setup(self, pin, mode):
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"""Set the input or output mode for a specified pin. Mode should be
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either OUTPUT or INPUT.
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"""
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self.bbio_gpio.setup(pin, self.bbio_gpio.IN if mode == IN else \
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self.bbio_gpio.OUT)
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def output(self, pin, value):
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"""Set the specified pin the provided high/low value. Value should be
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either HIGH/LOW or a boolean (true = high).
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"""
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self.bbio_gpio.output(pin, value)
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def input(self, pin):
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"""Read the specified pin and return HIGH/true if the pin is pulled high,
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or LOW/false if pulled low.
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"""
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return self.bbio_gpio.input(pin)
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def get_platform_gpio(plat=platform.platform(), **keywords):
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"""Attempt to return a GPIO instance for the platform which the code is being
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executed on. Currently supports only the Raspberry Pi using the RPi.GPIO
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library and Beaglebone Black using the Adafruit_BBIO library. Will throw an
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exception if a GPIO instance can't be created for the current platform. The
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returned GPIO object is an instance of BaseGPIO.
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"""
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if plat is None:
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raise RuntimeError('Could not determine platform type.')
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# TODO: Is there a better way to check if running on BBB or Pi? Relying on
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# the architecture name is brittle because new boards running armv6 or armv7
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# might come along and conflict with this simple identification scheme.
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# Handle Raspberry Pi
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# Platform output on Raspbian testing/jessie ~May 2014:
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# Linux-3.10.25+-armv6l-with-debian-7.4
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if plat.lower().find('armv6l-with-debian') > -1:
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import RPi.GPIO
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return RPiGPIOAdapter(RPi.GPIO, **keywords)
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# Handle Beaglebone Black
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# Platform output on Debian ~May 2014:
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# Linux-3.8.13-bone47-armv7l-with-debian-7.4
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if plat.lower().find('armv7l-with-debian') > -1:
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import Adafruit_BBIO.GPIO
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return AdafruitBBIOAdapter(Adafruit_BBIO.GPIO, **keywords)
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# Couldn't determine platform, raise error.
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raise RuntimeError('Unsupported platform: {0}'.format(plat))
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