This commit is a fairly major piece of work that abstracts all pin
operations (function, state, edge detection, PWM, etc.) into a base
"Pin" class which is then used by input/output/composite devices to
perform all required configuration.
The idea is to pave the way for I2C based IO extenders which can present
additional GPIO ports with similar capabilities to the Pi's "native"
GPIO ports. As a bonus it also abstracts away the reliance on the
RPi.GPIO library to allow alternative pin implementations (e.g. using
RPIO to take advantage of DMA based PWM), or even pure Python
implementations.
The prototypes in the docs are rigged to make out the first parameter as
mandatory (as it effectively is); however this does mean you've got to
remember to update the prototype when you modify it in the code! :)
Change parent of PWMOutputDevice to OutputDevice and implement blink to
maintain compatibility. The version of blink implemented here is
slightly extended to include functionality like Explorer HAT's "pulse".
The parameter defaults behave identically to OutputDevice's blink but
can be adjusted to have the device smoothly fade in and out.
This removes the circular dependency introduced in PR#137. This also
fixes up an issue in the base meta-class which meant it wasn't working
in Python 3 (only Python 2), and adds a bit to the meta-class to allow
docstrings to be inherited (taken from the rest-docs branch).
Add forward_device and backward_device to Motor, left_motor and
right_motor to Robot, and ensure all CompositeDevice descendents have a
proper close() method and closed property. Also, add a few more
_check_open calls around the place to make sure GPIODeviceClosed is
properly raised in response to read and writing values.
This finishes off implementing values and source for all (current)
classes in gpiozero. I'm afraid things get rather complex in this
commit. For starters, we've now got quite a few "aggregate" classes
which necessarily don't descend from GPIODevice. To implement values and
source on these I could either repeat a helluva lot of code or ... turn
to mixin classes. Yeah, it's multiple inheritance time, baby!
Unfortunately multiple inheritance doesn't work with __slots__ but we
really ought to keep functionality that they provide us (raise
AttributeError when an unknown attribute is set). So I've implemented
this with ... erm ... metaclasses. Sorry!
Makes `value` an alias of `is_active` in the base `GPIODevice`, and
`values` an infinite iterable of this value. Then adds `source` property
to `OutputDevice` allowing simple linkage of devices via iterators.
Add more property aliases and do them properly (no more lambdas and
string lookups) which means we can remove `_alias`. This commit also
defines `__slots__` for all classes which should prevent assignation of
invalid attributes with an AttributeError (more friendly than silently
doing the wrong thing). Finally, it cleans up all the property defs to
use Ben's preferred decorator style.
This PR adds the `active_high` parameter (defaulted to `True`) to the
`OutputDevice` class. This permits flipping the logic of an output
device in a similar manner to `pull_up` on `InputDevice`.
It also adds a `Relay` class derived from `DigitalOutputDevice` which
uses this parameter to flip the logic (as this is typically required
with relays).
Actually, this isn't so much a fix as a re-working of RGBLED. This
renames the `rgb` property to `color` because that's what the property
really represents (combined with `picamera.Color` this lets you do stuff
like `rgb_led.color = Color('red')`), and simplifies the internals of
the class. It also adds the common `close` method and context manager
capabilities.
Finally, it corrects an error I hadn't noticed earlier where
PWMOutputDevice isn't properly cleaning up PWM threads on close.
This refactors the GPIOOutputDevice to have an internal `_write` method
similar to the `_read` method used to grab the value of a GPIO device.
This is used for simple 1s and 0s until we get to PWMOutputDevice which
replaces the value with the PWM device's duty cycle level. As a result,
all the DigitalOutputDevice base methods (including blink) "just work".
This commit also, for the moment, removes min_pwm and max_pwm because
I'm not 100% certain how they should interact with the notion of
is_active at the moment. They'll probably get added back in at some
point but I need a bit more time to think about it!
This isn't a full fix but I can't seem to reproduce the issue in #50 at
the moment. So for now this just ensures that exceptions in the
constructors get cleaned up properly (so they don't block future
construction attempts against the same pin)
Big push on getting the docs cleaned up before 1.0. Proper wrapping of
everything so it's decently viewable from the command line (or as
decently viewable as markdown can be - the tables will never look great
from the command line).
Only one code change in this PR: rename bouncetime to bounce_time
(everything else is PEP-8, so this probably should be too) and change
its units to seconds from milliseconds (again, all other durations in
the library are in seconds, so it feels inconsistent that this one
isn't; for the sake of those who won't read the docs - which is most
people - I figure consistency helps with guessing!).
