kopia lustrzana https://github.com/peterhinch/micropython-samples
78 wiersze
2.2 KiB
Python
78 wiersze
2.2 KiB
Python
# encoder_rp2.py Uses the PIO for rapid response on RP2 chips (Pico)
|
|
|
|
# Copyright (c) 2022 Peter Hinch
|
|
# Released under the MIT License (MIT) - see LICENSE file
|
|
|
|
# PIO and SM code written by Sandor Attila Gerendi (@sanyi)
|
|
# https://github.com/micropython/micropython/pull/6894
|
|
|
|
from machine import Pin
|
|
from array import array
|
|
import rp2
|
|
|
|
# Test with encoder on pins 2 and 3:
|
|
# e = Encoder(0, Pin(2))
|
|
|
|
# while True:
|
|
# time.sleep(1)
|
|
# print(e.value())
|
|
|
|
# Closure enables Viper to retain state. Currently (V1.17) nonlocal doesn't
|
|
# work: https://github.com/micropython/micropython/issues/8086
|
|
# so using arrays.
|
|
def make_isr(pos):
|
|
old_x = array("i", (0,))
|
|
|
|
@micropython.viper
|
|
def isr(sm):
|
|
i = ptr32(pos)
|
|
p = ptr32(old_x)
|
|
while sm.rx_fifo():
|
|
v: int = int(sm.get()) & 3
|
|
x: int = v & 1
|
|
y: int = v >> 1
|
|
s: int = 1 if (x ^ y) else -1
|
|
i[0] = i[0] + (s if (x ^ p[0]) else (0 - s))
|
|
p[0] = x
|
|
|
|
return isr
|
|
|
|
|
|
# Args:
|
|
# StateMachine no. (0-7): each instance must have a different sm_no.
|
|
# An initialised input Pin: this and the next pin are the encoder interface.
|
|
# Pins must have pullups (internal or, preferably, low value 1KΩ to 3.3V).
|
|
class Encoder:
|
|
def __init__(self, sm_no, base_pin, scale=1):
|
|
self.scale = scale
|
|
self._pos = array("i", (0,)) # [pos]
|
|
self.sm = rp2.StateMachine(sm_no, self.pio_quadrature, in_base=base_pin)
|
|
self.sm.irq(make_isr(self._pos)) # Instantiate the closure
|
|
self.sm.exec("set(y, 99)") # Initialise y: guarantee different to the input
|
|
self.sm.active(1)
|
|
|
|
@rp2.asm_pio()
|
|
def pio_quadrature(in_init=rp2.PIO.IN_LOW):
|
|
wrap_target()
|
|
label("again")
|
|
in_(pins, 2)
|
|
mov(x, isr)
|
|
jmp(x_not_y, "push_data")
|
|
mov(isr, null)
|
|
jmp("again")
|
|
label("push_data")
|
|
push()
|
|
irq(block, rel(0))
|
|
mov(y, x)
|
|
wrap()
|
|
|
|
def position(self, value=None):
|
|
if value is not None:
|
|
self._pos[0] = round(value / self.scale)
|
|
return self._pos[0] * self.scale
|
|
|
|
def value(self, value=None):
|
|
if value is not None:
|
|
self._pos[0] = value
|
|
return self._pos[0]
|