Python Timer.period方法代码示例

# 需要导入模块: from pyb import Timer [as 别名]
# 或者: from pyb.Timer import period [as 别名]
class UltraSonicMeter(object):

    def __init__(self):
        self.tmp = self.time = 0
        self.cnt = 0
        self.fr = 0
        self.trig = Pin('X12', Pin.OUT_PP, Pin.PULL_NONE)
        echoR = Pin('X1', Pin.IN, Pin.PULL_NONE)
        echoF = Pin('X2', Pin.IN, Pin.PULL_NONE)
        self.micros = pyb.Timer(5, prescaler=83, period=0x3fffffff)
        self.timer = Timer(2, freq=1000)
        self.timer.period(3600)
        self.timer.prescaler(1375)
        self.timer.callback(lambda e: self.run_trig())
        extR = ExtInt(echoR, ExtInt.IRQ_RISING, Pin.PULL_NONE, self.start_count)
        extF = ExtInt(echoF, ExtInt.IRQ_FALLING, Pin.PULL_NONE, self.read_dist)

    def run_trig(self):
        self.trig.high()
        pyb.udelay(1)
        self.trig.low()

    def start_count(self, line):
        self.micros.counter(0)
        self.time = self.micros.counter()
        self.timer.counter(0)

    def read_dist(self, line):
        end = self.micros.counter()
        micros = end-self.time
        distP1 = micros//5
        distP2 = micros//6
        distP3 = (distP1-distP2)//10*2
        dist = distP2+distP3

        if dist != 0:
            self.cnt += 1
            self.fr += dist

        if self.cnt == 15:
            tmp = self.tmp
            dist = self.fr//self.cnt
            if tmp != dist:
                print(dist, 'mm')
                self.tmp = dist
            self.cnt = 0
            self.fr  = 0

# 需要导入模块: from pyb import Timer [as 别名]
# 或者: from pyb.Timer import period [as 别名]
# check basic functionality of the timer class

import pyb
from pyb import Timer

tim = Timer(4)
tim = Timer(4, prescaler=100, period=200)
print(tim.prescaler())
print(tim.period())
tim.prescaler(300)
print(tim.prescaler())
tim.period(400)
print(tim.period())

# 需要导入模块: from pyb import Timer [as 别名]
# 或者: from pyb.Timer import period [as 别名]
class Encoder():
    """
    Abstracts a quadrature encoder to give a tick count.
    The count is a signed integer starting at zero. It wraps the count from the
    attached timer to give a seamless and continuous tick count. Overflows of
    the internal timer counter register should be adequatly handled. If
    overflows or weird behaviour occurs around the overflow points, try
    increasing Encoder.HYSTERESIS.
    Note: Only works on pin pairs 'X1' & 'X2', 'X9' & 'X10', or 'Y1', 'Y2'. The
    timer will be automatically selected. Both Timer 2 and 5 work for 'X1' &
    'X2', but Timer 5 is preferred because Timer 2 is used for LED PWM but both
    can be used by changing the values of Encoder.AF_MAP.
    """
    # Constant for decoding in single line mode
    SINGLE_MODE = Timer.ENC_A
    # Constant for decoding in quad mode
    DUAL_MODE = Timer.ENC_AB
    # Maps alternate pin function descriptions to the required timer number
    TIMER_MAP = {'AF1_TIM2': 2, 'AF2_TIM4': 4, 'AF2_TIM5': 5, 'AF3_TIM8': 8}
    # Maps pin names to the alternate function to use
    AF_MAP = {'X1' : 'AF2_TIM5', 'X2': 'AF2_TIM5', 'X9': 'AF2_TIM4',
              'X10': 'AF2_TIM4', 'Y1': 'AF3_TIM8', 'Y2': 'AF3_TIM8'}
    # Defines the pin pairs that must be used
    PIN_PAIRS = [['X1','X9','Y1'],['X2','X10','Y2']]
    # Hysteresis value to overflow detection
    HYSTERESIS = 12 # One full rotation of encoder

    def __init__(self, pinA, pinB, mode = DUAL_MODE):
        """
        Instantiate an Encoder object.
        Initalises the Pins, Timer and TimerChannel for use as a quadrature
        decoder. Registers an overflow callback to elegantly handle counter
        register overflows.
        pinA: Any valid value taken by pyb.Pin constructor
        pinB: Any valid value taken by pyb.Pin constructor
        mode: Mode to use for decoding (Encoder.SINGLE_MODE or
                Encoder.DUAL_MODE)
        raises: Any exception thrown by pyb.Pin, pyb.Timer, pyb.Timer.channel
                or Exception if pins are not compatible pairs
        """
        self._chA = Pin(pinA)
        self._chB = Pin(pinB)
        self._ticks = 0

        # Check pins are compatible
        self._checkPins(pinA, pinB)

        # init pins for alternate encoder function
        af = self.AF_MAP[self._chA.names()[1]]
        channel = self.TIMER_MAP[af]
        af = getattr(Pin, af)
        self._chA.init(Pin.AF_PP, pull = Pin.PULL_NONE, af = af)
        self._chB.init(Pin.AF_PP, pull = Pin.PULL_NONE, af = af)
        # init timer
        self._timer = Timer(channel, prescaler = 0, period = 100000)
        # init encoder mode
        # self._channel = self._timer.channel(1, mode)
        self._timer.channel(1, mode)
        # setup overflow callback
        self._timer.callback(self._overflow)
        # init count register to middle of count
        self._timer.counter(self._timer.period()//2)
        self._lastRead = self._timer.counter()

    def _checkPins(self, pinA, pinB):
        """
        Check that two pins can be used for a decoding and are on the same
        timer.
        """
        try:
            if pinA in self.PIN_PAIRS[0]:
                if self.PIN_PAIRS[0].index(pinA) != self.PIN_PAIRS[1].index(pinB):
                    raise Exception()
            elif pinA in self.PIN_PAIRS[1]:
                if self.PIN_PAIRS[0].index(pinB) != self.PIN_PAIRS[1].index(pinA):
                    raise Exception()
            else:
                raise Exception()
        except:
            raise Exception(pinA + ' & ' + pinB + ' are not on the same Timer')

    def ticks(self, ticks = None):
        """
        Get or set the current tick count.
        Ticks is a signed integer.
        """
        if ticks is not None: # set ticks to desired value
            self._ticks = ticks
        else: # retrieve latest count and update internals
            count = self._timer.counter()
            self._ticks = self._ticks + (count - self._lastRead)
            self._lastRead = count
        return self._ticks

    def _overflow(self, timer):
        """
        Timer overflow callback to gracefully handle overflow events. If
        weird things are occurring, try increasing the HYSTERESIS value.
        """
        count = timer.counter()
#.........这里部分代码省略.........