This tutorial demonstrates how to flash CircuitPython onto an inexpensive nRF52840 dongle using OpenOCD and a Raspberry Pi. The Bluefruit LE Connect app will also be used to control the dongle from a mobile phone using BLE.
A quick introduction to CircuitPython. A Raspberry Pi will be used to load the bootloader on a Nordic nRF52840 board and run the Mu IDE. Adafruit Blinka will also be used to demonstrate code compatibility between the Pi and the microcontroller. Code demos include GPIO and BLE.