4. 有关于PCA9685的问题
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    • 有关于PCA9685的问题

    • B

      为什么我按照官网上的例程复制的代码在控制舵机时一直会报错？
      下面第一段是报错提示

      Traceback (most recent call last):
  File "<stdin>", line 10, in <module>
  File "servo.py", line 10, in __init__
  File "pca9685.py", line 17, in __init__
  File "pca9685.py", line 35, in reset
  File "pca9685.py", line 23, in _write
OSError: [Errno 110] ETIMEDOUT
MicroPython v1.9.4-4548-g24c934f79 on 2019-03-23; OPENMV4 with STM32H743
Type "help()" for more information.
>>>

      以下是官网复制的例程

      import utime

import ustruct



class PCA9685:

    def __init__(self, i2c, address=0x40):

        self.i2c = i2c

        self.address = address

        self.reset()



    def _write(self, address, value):

        self.i2c.writeto_mem(self.address, address, bytearray([value]))



    def _read(self, address):

        return self.i2c.readfrom_mem(self.address, address, 1)[0]



    def reset(self):

        self._write(0x00, 0x00) # Mode1



    def freq(self, freq=None):

        if freq is None:

            return int(25000000.0 / 4096 / (self._read(0xfe) - 0.5))

        prescale = int(25000000.0 / 4096.0 / freq + 0.5)

        old_mode = self._read(0x00) # Mode 1

        self._write(0x00, (old_mode & 0x7F) | 0x10) # Mode 1, sleep

        self._write(0xfe, prescale) # Prescale

        self._write(0x00, old_mode) # Mode 1

        utime.sleep_us(5)

        self._write(0x00, old_mode | 0xa1) # Mode 1, autoincrement on



    def pwm(self, index, on=None, off=None):

        if on is None or off is None:

            data = self.i2c.readfrom_mem(self.address, 0x06 + 4 * index, 4)

            return ustruct.unpack('<HH', data)

        data = ustruct.pack('<HH', on, off)

        self.i2c.writeto_mem(self.address, 0x06 + 4 * index,  data)



    def duty(self, index, value=None, invert=False):

        if value is None:

            pwm = self.pwm(index)

            if pwm == (0, 4096):

                value = 0

            elif pwm == (4096, 0):

                value = 4095

            value = pwm[1]

            if invert:

                value = 4095 - value

            return value

        if not 0 <= value <= 4095:

            raise ValueError("Out of range")

        if invert:

            value = 4095 - value

        if value == 0:

            self.pwm(index, 0, 4096)

        elif value == 4095:

            self.pwm(index, 4096, 0)

        else:

            self.pwm(index, 0, value)
      0

    • 应该是没有插好。
      按照视频步骤操作。https://singtown.com/learn/50057/

      0