From: Melissa LeBlanc-Williams Date: Tue, 11 Feb 2025 21:05:50 +0000 (-0800) Subject: Add PIO implementation of rotaryio for the Pi 5 X-Git-Tag: 8.54.0^2~2 X-Git-Url: https://git.ayoreis.com/Adafruit_Blinka-hackapet.git/commitdiff_plain/d21bd2e848c5198b238bf30fd3b953deb3d1c805 Add PIO implementation of rotaryio for the Pi 5 --- diff --git a/src/adafruit_blinka/microcontroller/bcm283x/rotaryio.py b/src/adafruit_blinka/microcontroller/bcm283x/rotaryio.py new file mode 100644 index 0000000..c4c54c3 --- /dev/null +++ b/src/adafruit_blinka/microcontroller/bcm283x/rotaryio.py @@ -0,0 +1,198 @@ +# SPDX-FileCopyrightText: 2025 Melissa LeBlanc-Williams for Adafruit Industries +# +# SPDX-License-Identifier: MIT +""" +`rotaryio` - Support for reading rotation sensors +=========================================================== +See `CircuitPython:rotaryio` in CircuitPython for more details. + +Raspberry Pi PIO implementation + +* Author(s): Melissa LeBlanc-Williams +""" + +from __future__ import annotations +import microcontroller +import array +try: + import adafruit_pioasm + from adafruit_rp1pio import StateMachine +except ImportError: + raise("adafruit_pioasm and adafruit_rp1pio are required for this module") + +_n_read = 17 +_program = adafruit_pioasm.Program(""" +; +; Copyright (c) 2023 Raspberry Pi (Trading) Ltd. +; +; SPDX-License-Identifier: BSD-3-Clause +; +.pio_version 0 // only requires PIO version 0 + +.program quadrature_encoder + +; the code must be loaded at address 0, because it uses computed jumps +.origin 0 + + +; the code works by running a loop that continuously shifts the 2 phase pins into +; ISR and looks at the lower 4 bits to do a computed jump to an instruction that +; does the proper "do nothing" | "increment" | "decrement" action for that pin +; state change (or no change) + +; ISR holds the last state of the 2 pins during most of the code. The Y register +; keeps the current encoder count and is incremented / decremented according to +; the steps sampled + +; the program keeps trying to write the current count to the RX FIFO without +; blocking. To read the current count, the user code must drain the FIFO first +; and wait for a fresh sample (takes ~4 SM cycles on average). The worst case +; sampling loop takes 10 cycles, so this program is able to read step rates up +; to sysclk / 10 (e.g., sysclk 125MHz, max step rate = 12.5 Msteps/sec) + +; 00 state + jmp update ; read 00 + jmp decrement ; read 01 + jmp increment ; read 10 + jmp update ; read 11 + +; 01 state + jmp increment ; read 00 + jmp update ; read 01 + jmp update ; read 10 + jmp decrement ; read 11 + +; 10 state + jmp decrement ; read 00 + jmp update ; read 01 + jmp update ; read 10 + jmp increment ; read 11 + +; to reduce code size, the last 2 states are implemented in place and become the +; target for the other jumps + +; 11 state + jmp update ; read 00 + jmp increment ; read 01 +decrement: + ; note: the target of this instruction must be the next address, so that + ; the effect of the instruction does not depend on the value of Y. The + ; same is true for the "jmp y--" below. Basically "jmp y--, " + ; is just a pure "decrement y" instruction, with no other side effects + jmp y--, update ; read 10 + + ; this is where the main loop starts +.wrap_target +update: + mov isr, y ; read 11 + push noblock + +sample_pins: + ; we shift into ISR the last state of the 2 input pins (now in OSR) and + ; the new state of the 2 pins, thus producing the 4 bit target for the + ; computed jump into the correct action for this state. Both the PUSH + ; above and the OUT below zero out the other bits in ISR + out isr, 2 + in pins, 2 + + ; save the state in the OSR, so that we can use ISR for other purposes + mov osr, isr + ; jump to the correct state machine action + mov pc, isr + + ; the PIO does not have a increment instruction, so to do that we do a + ; negate, decrement, negate sequence +increment: + mov y, ~y + jmp y--, increment_cont +increment_cont: + mov y, ~y +.wrap ; the .wrap here avoids one jump instruction and saves a cycle too +""") + +_zero_y = adafruit_pioasm.assemble("set y 0") + +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 incremental encoder on pin_a and the next higher pin + + Always operates in "x4" mode (one count per quadrature edge) + + Assumes but does not check that pin_b is one above pin_a.""" + #if pin_b is not None and pin_b.id != pin_a.id + 1: + # raise ValueError("pin_b must be None or one higher than pin_a") + + try: + self._sm = StateMachine( + _program.assembled, + frequency=0, + init=_zero_y, + first_in_pin=pin_a, + in_pin_count=2, + pull_in_pin_up=0x3, + auto_push=True, + push_threshold=32, + in_shift_right=False, + **_program.pio_kwargs + ) + except RuntimeError as e: + if "(error -13)" in e.args[0]: + raise RuntimeError( + "This feature requires a rules file to allow access to PIO. See " + "https://learn.adafruit.com/circuitpython-on-raspberrypi-linux/using-neopixels-on-the-pi-5#updating-permissions-3189429" + ) from e + raise + self._buffer = array.array('i',[0] * _n_read) + self.divisor = divisor + self._position = 0 + + def deinit(self): + """Deinitializes the IncrementalEncoder and releases any hardware resources for reuse.""" + self._sm.deinit() + + 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 position(self): + self._sm.readinto(self._buffer) # read N stale values + 1 fresh value + raw_position = self._buffer[-1] + delta = int((raw_position - self._position * self.divisor) / self.divisor) + self._position += delta + return self._position + +''' +if __name__ == '__main__': + import board + # D17/D18 on header pins 11/12 + # GND on header pin 6/9 + # +5V on header pins 2/4 + q = IncrementalEncoder(board.D17) + old_position = q.position + while True: + position = q.position + if position != old_position: + delta = position - old_position + print(f"{position:8d} {delta=}") + old_position = position +''' \ No newline at end of file diff --git a/src/adafruit_blinka/microcontroller/generic_linux/rotaryio.py b/src/adafruit_blinka/microcontroller/generic_linux/rotaryio.py new file mode 100644 index 0000000..f2a55d0 --- /dev/null +++ b/src/adafruit_blinka/microcontroller/generic_linux/rotaryio.py @@ -0,0 +1,139 @@ +# SPDX-FileCopyrightText: 2025 Melissa LeBlanc-Williams for Adafruit Industries +# +# SPDX-License-Identifier: MIT +""" +`rotaryio` - Support for reading rotation sensors +=========================================================== +See `CircuitPython:rotaryio` in CircuitPython for more details. + +Generic Threading/DigitalIO implementation for Linux + +* Author(s): Melissa LeBlanc-Williams +""" + +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 diff --git a/src/rotaryio.py b/src/rotaryio.py index 7c30332..d81ae5c 100644 --- a/src/rotaryio.py +++ b/src/rotaryio.py @@ -9,129 +9,14 @@ See `CircuitPython:rotaryio` in CircuitPython for more details. * Author(s): Melissa LeBlanc-Williams """ -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 +from adafruit_blinka.agnostic import detector + +# Import any board specific modules here +if detector.board.any_raspberry_pi_5_board: + from adafruit_blinka.microcontroller.bcm283x.rotaryio import IncrementalEncoder +elif detector.board.any_embedded_linux: + #fall back to the generic linux implementation + from adafruit_blinka.microcontroller.generic_linux.rotaryio import IncrementalEncoder +else: + # For non-Linux Boards, threading likely will work in the same way + raise NotImplementedError("Board not supported")