kopia lustrzana https://github.com/peterhinch/micropython-samples
74 wiersze
2.1 KiB
Python
74 wiersze
2.1 KiB
Python
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# encoder_rp2.py Uses the PIO for rapid response on RP2 chips (Pico)
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# Copyright (c) 2022 Peter Hinch
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# Released under the MIT License (MIT) - see LICENSE file
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# PIO and SM code written by Sandor Attila Gerendi (@sanyi)
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# https://github.com/micropython/micropython/pull/6894
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from machine import Pin
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from array import array
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import rp2
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# Test with encoder on pins 2 and 3:
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#e = Encoder(0, Pin(2))
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#while True:
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#time.sleep(1)
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#print(e.value())
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# Closure enables Viper to retain state. Currently (V1.17) nonlocal doesn't
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# work: https://github.com/micropython/micropython/issues/8086
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# so using arrays.
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def make_isr(pos):
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old_x = array('i', (0,))
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@micropython.viper
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def isr(sm):
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i = ptr32(pos)
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p = ptr32(old_x)
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while sm.rx_fifo():
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v : int = int(sm.get()) & 3
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x : int = v & 1
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y : int = v >> 1
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s : int = 1 if (x ^ y) else -1
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i[0] = i[0] + (s if (x ^ p[0]) else (0 - s))
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p[0] = x
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return isr
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# Args:
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# StateMachine no. (0-7): each instance must have a different sm_no.
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# An initialised input Pin: this and the next pin are the encoder interface.
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class Encoder:
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def __init__(self, sm_no, base_pin, scale=1):
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self.scale = scale
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self._pos = array("i", (0,)) # [pos]
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self.sm = rp2.StateMachine(sm_no, self.pio_quadrature, in_base=base_pin)
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self.sm.irq(make_isr(self._pos)) # Instantiate the closure
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self.sm.exec("set(y, 99)") # Initialise y: guarantee different to the input
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self.sm.active(1)
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@rp2.asm_pio()
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def pio_quadrature(in_init=rp2.PIO.IN_LOW):
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wrap_target()
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label("again")
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in_(pins, 2)
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mov(x, isr)
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jmp(x_not_y, "push_data")
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mov(isr, null)
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jmp("again")
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label("push_data")
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push()
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irq(block, rel(0))
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mov(y, x)
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wrap()
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def position(self, value=None):
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if value is not None:
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self._pos[0] = round(value / self.scale)
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return self._pos[0] * self.scale
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def value(self, value=None):
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if value is not None:
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self._pos[0] = value
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return self._pos[0]
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