The nRF52840 MDK USB Dongle is a small, low-cost development board in a USB dongle form-factor powered by an nRF52840 with 1MB flash and 256KB RAM.
This device is pre-installed with Open Bootloader, allowing DFU upgrades over USB using Nordic nRF Connect or nrfutil. To support Open Bootloader, the flash and memory layout must be adjusted slightly (details here) from the typical nRF build; this board definition ensure the appropriate build configuration is used for MicroPython.
The pinout diagram provides an overview of the available pins and their capabilities. All pins are available in MicroPython, using the pin numbers labelled in the diagram (excluding the leading port number, P0).
The three LEDs are available either through the usual Pin mechanism - pins
22-24 - or by board.LED(n) where n can be 1, 2 or 3.
Follow the standard nRF Port build instructions; but use
nrf52840-mdk-usb-dongle as the value for BOARD:
make BOARD=nrf52840-mdk-usb-dongle
The build artifacts will be created in build-nrf52840-mdk-usb-dongle. Once
built, the target can be deployed to the device as described in
nRFUtil targets.
An alternative way to deploy to the device, is to open firmware.hex using
nRF Connect and select Write. Detailed instructions can be found on the
developer
wiki.