After I install pca9685() according to the online method, the following errors will appear in the operation.

>>> pwm = Adafruit_PCA9685.PCA9685()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'Adafruit_PCA9685' is not defined
>>> import Adafruit_PCA9685
>>> pwm = Adafruit_PCA9685.PCA9685()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.7/dist-packages/Adafruit_PCA9685-1.0.1-py3.7.egg/Adafruit_PCA9685/PCA9685.py", line 75, in __init__
    self.set_all_pwm(0, 0)
  File "/usr/local/lib/python3.7/dist-packages/Adafruit_PCA9685-1.0.1-py3.7.egg/Adafruit_PCA9685/PCA9685.py", line 111, in set_all_pwm
    self._device.write8(ALL_LED_ON_L, on & 0xFF)
  File "/usr/local/lib/python3.7/dist-packages/Adafruit_GPIO-1.0.4-py3.7.egg/Adafruit_GPIO/I2C.py", line 116, in write8
    self._bus.write_byte_data(self._address, register, value)
  File "/usr/local/lib/python3.7/dist-packages/Adafruit_PureIO-1.1.9-py3.7.egg/Adafruit_PureIO/smbus.py", line 327, in write_byte_data
OSError: [Errno 121] Remote I/O error

 

But the premise of this method is to have the Adafruit_PCA9685 file under the path /usr/local/lib/python3.7/dist-packages/”, if there is one, use the above method

My Raspberry Pi is 4B, there are three .egg files in the above path, Adafruit_PCA9685 is placed in it, as shown below

Select the middle of the Adafruit_PCA9685 .egg file, there will be PCA9685.py file, just create PCA9685.py under raspberry home/pi/ and paste the contents of the previous PCA9685.py into the newly created file, import the code to import PCA9685 instead of not import Adafruit_PCA9685

import PCA9685

Open the PCA9685 file and find that it needs to import the I2C.py file (I forgot to take a screenshot), then open the first one under the /usr/local/lib/python3.7/dist-packages/ path

Paste the contents of I2C.py and Plaform.py inside this file into a new I2C.py and Plaform.py file under home/pi, then open the PCA9685.py file in this directory and change the imported I2C in the middle position, it seems to be form Adafurit_GPIO import I2C as I2C directly to import I2C.

Then open the I2C file, found that you need to import Plaform.py, the same operation, change the previous import to import Plaform can be, as shown, and finally in the directory I2C.py PCA9685.py and Plaform.py file

You can write it directly in the raspberry pie file

import PCA9685
pwm = PCA9685.PCA9685()

See if it’s successful. I’m successful.