from __future__ import (
unicode_literals,
absolute_import,
print_function,
division,
)
str = type('')
import warnings
from RPi import GPIO
from . import LocalPin
from .data import pi_info
from ..exc import (
PinInvalidFunction,
PinSetInput,
PinFixedPull,
PinInvalidPull,
PinInvalidState,
PinInvalidBounce,
PinPWMFixedValue,
PinNonPhysical,
PinNoPins,
)
[docs]class RPiGPIOPin(LocalPin):
"""
Uses the `RPi.GPIO`_ library to interface to the Pi's GPIO pins. This is
the default pin implementation if the RPi.GPIO library is installed.
Supports all features including PWM (via software).
Because this is the default pin implementation you can use it simply by
specifying an integer number for the pin in most operations, e.g.::
from gpiozero import LED
led = LED(12)
However, you can also construct RPi.GPIO pins manually if you wish::
from gpiozero.pins.rpigpio import RPiGPIOPin
from gpiozero import LED
led = LED(RPiGPIOPin(12))
.. _RPi.GPIO: https://pypi.python.org/pypi/RPi.GPIO
"""
_PINS = {}
GPIO_FUNCTIONS = {
'input': GPIO.IN,
'output': GPIO.OUT,
'i2c': GPIO.I2C,
'spi': GPIO.SPI,
'pwm': GPIO.HARD_PWM,
'serial': GPIO.SERIAL,
'unknown': GPIO.UNKNOWN,
}
GPIO_PULL_UPS = {
'up': GPIO.PUD_UP,
'down': GPIO.PUD_DOWN,
'floating': GPIO.PUD_OFF,
}
GPIO_EDGES = {
'both': GPIO.BOTH,
'rising': GPIO.RISING,
'falling': GPIO.FALLING,
}
GPIO_FUNCTION_NAMES = {v: k for (k, v) in GPIO_FUNCTIONS.items()}
GPIO_PULL_UP_NAMES = {v: k for (k, v) in GPIO_PULL_UPS.items()}
GPIO_EDGES_NAMES = {v: k for (k, v) in GPIO_EDGES.items()}
PI_INFO = None
def __new__(cls, number):
if not cls._PINS:
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
if cls.PI_INFO is None:
cls.PI_INFO = pi_info()
try:
return cls._PINS[number]
except KeyError:
self = super(RPiGPIOPin, cls).__new__(cls)
try:
cls.PI_INFO.physical_pin('GPIO%d' % number)
except PinNoPins:
warnings.warn(
PinNonPhysical(
'no physical pins exist for GPIO%d' % number))
self._number = number
self._pull = 'up' if cls.PI_INFO.pulled_up('GPIO%d' % number) else 'floating'
self._pwm = None
self._frequency = None
self._duty_cycle = None
self._bounce = -666
self._when_changed = None
self._edges = GPIO.BOTH
GPIO.setup(self._number, GPIO.IN, self.GPIO_PULL_UPS[self._pull])
cls._PINS[number] = self
return self
def __repr__(self):
return "GPIO%d" % self._number
@property
def number(self):
return self._number
def close(self):
self.frequency = None
self.when_changed = None
GPIO.cleanup(self._number)
def output_with_state(self, state):
self._pull = 'floating'
GPIO.setup(self._number, GPIO.OUT, initial=state)
def input_with_pull(self, pull):
if pull != 'up' and self.PI_INFO.pulled_up('GPIO%d' % self._number):
raise PinFixedPull('%r has a physical pull-up resistor' % self)
try:
GPIO.setup(self._number, GPIO.IN, self.GPIO_PULL_UPS[pull])
self._pull = pull
except KeyError:
raise PinInvalidPull('invalid pull "%s" for pin %r' % (pull, self))
def _get_function(self):
return self.GPIO_FUNCTION_NAMES[GPIO.gpio_function(self._number)]
def _set_function(self, value):
if value != 'input':
self._pull = 'floating'
if value in ('input', 'output') and value in self.GPIO_FUNCTIONS:
GPIO.setup(self._number, self.GPIO_FUNCTIONS[value], self.GPIO_PULL_UPS[self._pull])
else:
raise PinInvalidFunction('invalid function "%s" for pin %r' % (value, self))
def _get_state(self):
if self._pwm:
return self._duty_cycle
else:
return GPIO.input(self._number)
def _set_state(self, value):
if self._pwm:
try:
self._pwm.ChangeDutyCycle(value * 100)
except ValueError:
raise PinInvalidState('invalid state "%s" for pin %r' % (value, self))
self._duty_cycle = value
else:
try:
GPIO.output(self._number, value)
except ValueError:
raise PinInvalidState('invalid state "%s" for pin %r' % (value, self))
except RuntimeError:
raise PinSetInput('cannot set state of pin %r' % self)
def _get_pull(self):
return self._pull
def _set_pull(self, value):
if self.function != 'input':
raise PinFixedPull('cannot set pull on non-input pin %r' % self)
if value != 'up' and self.PI_INFO.pulled_up('GPIO%d' % self._number):
raise PinFixedPull('%r has a physical pull-up resistor' % self)
try:
GPIO.setup(self._number, GPIO.IN, self.GPIO_PULL_UPS[value])
self._pull = value
except KeyError:
raise PinInvalidPull('invalid pull "%s" for pin %r' % (value, self))
def _get_frequency(self):
return self._frequency
def _set_frequency(self, value):
if self._frequency is None and value is not None:
try:
self._pwm = GPIO.PWM(self._number, value)
except RuntimeError:
raise PinPWMFixedValue('cannot start PWM on pin %r' % self)
self._pwm.start(0)
self._duty_cycle = 0
self._frequency = value
elif self._frequency is not None and value is not None:
self._pwm.ChangeFrequency(value)
self._frequency = value
elif self._frequency is not None and value is None:
self._pwm.stop()
self._pwm = None
self._duty_cycle = None
self._frequency = None
def _get_bounce(self):
return None if self._bounce == -666 else (self._bounce / 1000)
def _set_bounce(self, value):
if value is not None and value < 0:
raise PinInvalidBounce('bounce must be 0 or greater')
f = self.when_changed
self.when_changed = None
try:
self._bounce = -666 if value is None else int(value * 1000)
finally:
self.when_changed = f
def _get_edges(self):
return self.GPIO_EDGES_NAMES[self._edges]
def _set_edges(self, value):
f = self.when_changed
self.when_changed = None
try:
self._edges = self.GPIO_EDGES[value]
finally:
self.when_changed = f
def _get_when_changed(self):
return self._when_changed
def _set_when_changed(self, value):
if self._when_changed is None and value is not None:
self._when_changed = value
GPIO.add_event_detect(
self._number, self._edges,
callback=lambda channel: self._when_changed(),
bouncetime=self._bounce)
elif self._when_changed is not None and value is None:
GPIO.remove_event_detect(self._number)
self._when_changed = None
else:
self._when_changed = value