PWM Shield: useful links

PCA9865 with CircuitPython

https://stackoverflow.com/questions/54432417/rpi-servo-hat-python3-library-throwing-error-board-has-no-attribute-scl https://github.com/adafruit/Adafruit_CircuitPython_ServoKit/issues/7 https://github.com/adafruit/Adafruit_Blinka/blob/master/src/busio.py https://github.com/adafruit/Adafruit_Blinka/issues/66 https://github.com/adafruit/Adafruit_Blinka/issues/99

Article that seems to be good and perhaps used later: http://nascivera.it/2017/11/20/adafruit-i2c-tinkerboard/

Old deprecated PCA9865 library that throws "connection timed out":

https://github.com/adafruit/Adafruit_Python_PCA9685/issues

Digging into the error brought me here: https://github.com/adafruit/Adafruit_Python_PureIO/blob/master/Adafruit_PureIO/smbus.py

Also might be helpful: https://forums.adafruit.com/viewtopic.php?f=50&t=144979&p=716015&hilit=pca9865#p716015

Datasheet: https://cdn-shop.adafruit.com/datasheets/PCA9685.pdf

---AUDIO--- https://learn.adafruit.com/adding-basic-audio-ouput-to-raspberry-pi-zero/pi-zero-pwm-audio (guide for PWM audio setup on RPi Zero) -Unfortunately, on NanoPi DUO there is only one PWM Pin which is DRX so I can't debug the device and use it simultaneously -also, there is no config file in /boot/ I'm curious about how they transmit audio to 3.5 mm jack on extension board: http://wiki.friendlyarm.com/wiki/index.php/Mini_Shield_for_NanoPi_Duo