-from __future__ import annotations
-import threading
-import microcontroller
-import digitalio
-
-# Define the state transition table for the quadrature encoder
-transitions = [
- 0, # 00 -> 00 no movement
- -1, # 00 -> 01 3/4 ccw (11 detent) or 1/4 ccw (00 at detent)
- +1, # 00 -> 10 3/4 cw or 1/4 cw
- 0, # 00 -> 11 non-Gray-code transition
- +1, # 01 -> 00 2/4 or 4/4 cw
- 0, # 01 -> 01 no movement
- 0, # 01 -> 10 non-Gray-code transition
- -1, # 01 -> 11 4/4 or 2/4 ccw
- -1, # 10 -> 00 2/4 or 4/4 ccw
- 0, # 10 -> 01 non-Gray-code transition
- 0, # 10 -> 10 no movement
- +1, # 10 -> 11 4/4 or 2/4 cw
- 0, # 11 -> 00 non-Gray-code transition
- +1, # 11 -> 01 1/4 or 3/4 cw
- -1, # 11 -> 10 1/4 or 3/4 ccw
- 0, # 11 -> 11 no movement
-]
-
-
-class IncrementalEncoder:
- """
- IncrementalEncoder determines the relative rotational position based on two series of
- pulses. It assumes that the encoder’s common pin(s) are connected to ground,and enables
- pull-ups on pin_a and pin_b.
-
- Create an IncrementalEncoder object associated with the given pins. It tracks the
- positional state of an incremental rotary encoder (also known as a quadrature encoder.)
- Position is relative to the position when the object is constructed.
- """
-
- def __init__(
- self, pin_a: microcontroller.Pin, pin_b: microcontroller.Pin, divisor: int = 4
- ):
- """
- Create an IncrementalEncoder object associated with the given pins. It tracks the
- positional state of an incremental rotary encoder (also known as a quadrature encoder.)
- Position is relative to the position when the object is constructed.
-
- :param microcontroller.Pin pin_a: The first pin connected to the encoder.
- :param microcontroller.Pin pin_b: The second pin connected to the encoder.
- :param int divisor: The number of pulses per encoder step. Default is 4.
- """
- self._pin_a = digitalio.DigitalInOut(pin_a)
- self._pin_a.switch_to_input(pull=digitalio.Pull.UP)
- self._pin_b = digitalio.DigitalInOut(pin_b)
- self._pin_b.switch_to_input(pull=digitalio.Pull.UP)
- self._position = 0
- self._last_state = 0
- self._divisor = divisor
- self._sub_count = 0
- self._poll_thread = threading.Thread(target=self._polling_loop, daemon=True)
- self._poll_thread.start()
-
- def deinit(self):
- """Deinitializes the IncrementalEncoder and releases any hardware resources for reuse."""
- self._pin_a.deinit()
- self._pin_b.deinit()
- if self._poll_thread.is_alive():
- self._poll_thread.join()
-
- def __enter__(self) -> IncrementalEncoder:
- """No-op used by Context Managers."""
- return self
-
- def __exit__(self, _type, _value, _traceback):
- """
- Automatically deinitializes when exiting a context. See
- :ref:`lifetime-and-contextmanagers` for more info.
- """
- self.deinit()
-
- @property
- def divisor(self) -> int:
- """The divisor of the quadrature signal. Use 1 for encoders without detents, or encoders
- with 4 detents per cycle. Use 2 for encoders with 2 detents per cycle. Use 4 for encoders
- with 1 detent per cycle."""
- return self._divisor
-
- @divisor.setter
- def divisor(self, value: int):
- self._divisor = value
-
- @property
- def position(self) -> int:
- """The current position in terms of pulses. The number of pulses per rotation is defined
- by the specific hardware and by the divisor."""
- return self._position
-
- @position.setter
- def position(self, value: int):
- self._position = value
-
- def _get_pin_state(self) -> int:
- """Returns the current state of the pins."""
- return self._pin_a.value << 1 | self._pin_b.value
-
- def _polling_loop(self):
- while True:
- self._poll_encoder()
-
- def _poll_encoder(self):
- # Check the state of the pins
- # if either pin has changed, update the state
- new_state = self._get_pin_state()
- if new_state != self._last_state:
- self._state_update(new_state)
- self._last_state = new_state
-
- def _state_update(self, new_state: int):
- new_state &= 3
- index = self._last_state << 2 | new_state
- sub_increment = transitions[index]
- self._sub_count += sub_increment
- if self._sub_count >= self._divisor:
- self._position += 1
- self._sub_count = 0
- elif self._sub_count <= -self._divisor:
- self._position -= 1
- self._sub_count = 0
projects / Adafruit_Blinka-hackapet.git / blobdiff