kopia lustrzana https://github.com/peterhinch/micropython-micro-gui
77 wiersze
2.9 KiB
Python
77 wiersze
2.9 KiB
Python
# encoder.py Asynchronous driver for incremental quadrature encoder.
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# Copyright (c) 2021-2022 Peter Hinch
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# Released under the MIT License (MIT) - see LICENSE file
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import uasyncio as asyncio
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from machine import Pin
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class Encoder:
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delay = 100 # Pause (ms) for motion to stop
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def __init__(self, pin_x, pin_y, v=0, vmin=None, vmax=None, div=1,
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callback=lambda a, b : None, args=(), mod=0):
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self._pin_x = pin_x
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self._pin_y = pin_y
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self._x = pin_x()
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self._y = pin_y()
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self._v = 0 # Initialise hardware value
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self._cv = v # Current (divided) value
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if ((vmin is not None) and v < vmin) or ((vmax is not None) and v > vmax):
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raise ValueError('Incompatible args: must have vmin <= v <= vmax')
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self._tsf = asyncio.ThreadSafeFlag()
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trig = Pin.IRQ_RISING | Pin.IRQ_FALLING
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try:
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xirq = pin_x.irq(trigger=trig, handler=self._x_cb, hard=True)
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yirq = pin_y.irq(trigger=trig, handler=self._y_cb, hard=True)
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except TypeError: # hard arg is unsupported on some hosts
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xirq = pin_x.irq(trigger=trig, handler=self._x_cb)
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yirq = pin_y.irq(trigger=trig, handler=self._y_cb)
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asyncio.create_task(self._run(vmin, vmax, div, mod, callback, args))
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# Hardware IRQ's. Duration 36μs on Pyboard 1 ~50μs on ESP32.
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# IRQ latency: 2nd edge may have occured by the time ISR runs, in
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# which case there is no movement.
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def _x_cb(self, pin_x):
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if (x := pin_x()) != self._x:
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self._x = x
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self._v += 1 if x ^ self._pin_y() else -1
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self._tsf.set()
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def _y_cb(self, pin_y):
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if (y := pin_y()) != self._y:
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self._y = y
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self._v -= 1 if y ^ self._pin_x() else -1
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self._tsf.set()
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async def _run(self, vmin, vmax, div, modulo, cb, args):
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pv = self._v # Prior hardware value
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cv = self._cv # Current divided value as passed to callback
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pcv = cv # Prior divided value passed to callback
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delay = self.delay
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while True:
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await self._tsf.wait()
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await asyncio.sleep_ms(delay) # Wait for motion to stop
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new = self._v # Sample hardware (atomic read)
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a = new - pv # Hardware change
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# Ensure symmetrical bahaviour for + and - values
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q, r = divmod(abs(a), div)
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if a < 0:
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r = -r
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q = -q
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pv = new - r # Hardware value when local value was updated
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cv += q
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if vmax is not None:
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cv = min(cv, vmax)
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if vmin is not None:
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cv = max(cv, vmin)
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if modulo:
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cv %= modulo
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self._cv = cv # For value()
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if cv != pcv:
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cb(cv, cv - pcv, *args) # User CB in uasyncio context
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pcv = cv
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def value(self):
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return self._cv
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