Question
How to fix AdaFruit CircuitPython Blinka Servo Board Installation Problem?
Answer
There are many reasons for not successfully installing CircuitPython Blinka, including the following:
(1) Not using pip3,
(2) Not using latest version of raspbian update and upgrade
I have successfull installed Blinka and CircuitPython on Rpi4B buster (release 2019sep26). I have also made a summary for you to compare and contrast your installation. You can also read the full installation record in Reference 2 below:
Circuit Python and Blinka Installation Summary
pi@tlfong01:~ $ date Sun 03 Nov 2019 09:51:49 AM HKT
pi@tlfong01:~ $ uname -a Linux tlfong01 4.19.75-v7l+ #1270 SMP Tue Sep
24 18:51:41 BST 2019 armv7l GNU/Linux
pi@tlfong01:~ $ sudo apt-get update
pi@tlfong01:~ $ sudo apt-get upgrade
pi@tlfong01:~ $ sudo pip3 install --upgrade setuptools
pi@tlfong01:~ $ pip3 install RPI.GPIO
pi@tlfong01:~ $ pip3 install adafruit-blinka
Successfully installed Adafruit-PlatformDetect-1.3.4
Adafruit-PureIO-0.2.3 adafruit-blinka-3.0.0 rpi-ws281x-4.2.2
sysv-ipc-1.0.0
References
(1) Installing AdaFruit CircuitPython Blinka Libraries on Raspberry Pi - Lada Ada
(2) CircuitPython Blinka Rpi4B buster Installation Record - tlfong01
(3) Adafruit MicroPython (Not CircuitPython) Blinka Installation Problem - drfuzzyness 2018sep15
(4) Adafruit Blinka For Non CircuitPython Python Such As Linux and MicroPython - pyPi
(5) Adafruit_Blinka Updated Bus IO Error Type - AdaFruit Blinka GitHub
(6) Rpi4B buster CircuitPython Blinka Servo Board Installation Problem
(7) Electronics Newbies's Guide to Setup Adafruit PCA9685 16 Channel Servo Driver for Raspberry Pi - @Hammerstein 2014sep10
(8) AdaFruit Python Installation of PCA9685 ServoKit Library - Kevin Townsend 2012aug16
Appendices
Appendix A - Differences between CircuitPython Blinka and MicroPython Blinka
Introduction
This repository contains a selection of packages mirroring the CircuitPython API on hosts running micropython.
board - breakout-specific pin identities
microcontroller - chip-specific pin identities
digitalio - digital input/output pins, using pin identities from
board+microcontroller packages
bitbangio - software-driven interfaces for I2C, SPI
busio - hardware-driven interfaces for I2C, SPI, UART
time - substitute functions monkey-patched to time module
Dependencies
The Micropython compatibility layers described above are intended to provide a CircuitPython-like API for devices which are running CPython or Micropython.
End of answer