micropython-samples/encoders/encoder_portable.py

# encoder_portable.py

# Encoder Support: this version should be portable between MicroPython platforms
# Thanks to Evan Widloski for the adaptation to use the machine module

# Copyright (c) 2017-2022 Peter Hinch
# Released under the MIT License (MIT) - see LICENSE file

from machine import Pin

class Encoder:
    def __init__(self, pin_x, pin_y, scale=1):
        self.scale = scale
        self.forward = True
        self.pin_x = pin_x
        self.pin_y = pin_y
        self._x = pin_x()
        self._y = pin_y()
        self._pos = 0
        try:
            self.x_interrupt = pin_x.irq(trigger=Pin.IRQ_RISING | Pin.IRQ_FALLING, handler=self.x_callback, hard=True)
            self.y_interrupt = pin_y.irq(trigger=Pin.IRQ_RISING | Pin.IRQ_FALLING, handler=self.y_callback, hard=True)
        except TypeError:
            self.x_interrupt = pin_x.irq(trigger=Pin.IRQ_RISING | Pin.IRQ_FALLING, handler=self.x_callback)
            self.y_interrupt = pin_y.irq(trigger=Pin.IRQ_RISING | Pin.IRQ_FALLING, handler=self.y_callback)

    def x_callback(self, pin_x):
        if (x := pin_x()) != self._x:  # Reject short pulses
            self._x = x
            self.forward = x ^ self.pin_y()
            self._pos += 1 if self.forward else -1

    def y_callback(self, pin_y):
        if (y := pin_y()) != self._y:
            self._y = y
            self.forward = y ^ self.pin_x() ^ 1
            self._pos += 1 if self.forward else -1

    def position(self, value=None):
        if value is not None:
            self._pos = round(value / self.scale)  # Improvement provided by @IhorNehrutsa
        return self._pos * self.scale

    def value(self, value=None):
        if value is not None:
            self._pos = value
        return self._pos