# Nordic Semiconductor nRF52 Series This is a port of CircuitPython to the Nordic Semiconductor nRF52 series of chips. > **NOTE**: There are board-specific READMEs that may be more up to date than the generic board-neutral documentation below. ## Flash Some boards have UF2 bootloaders and can simply be flashed in the normal way, by copying firmware.uf2 to the BOOT drive. For some boards, you can use the `flash` target: make BOARD=pca10056 flash ## Segger Targets Install the necessary tools to flash and debug using Segger: [JLink Download](https://www.segger.com/downloads/jlink#) [nrfjprog linux-32bit Download](https://www.nordicsemi.com/eng/nordic/download_resource/52615/16/95882111/97746) [nrfjprog linux-64bit Download](https://www.nordicsemi.com/eng/nordic/download_resource/51386/21/77886419/94917) [nrfjprog osx Download](https://www.nordicsemi.com/eng/nordic/download_resource/53402/12/97293750/99977) [nrfjprog win32 Download](https://www.nordicsemi.com/eng/nordic/download_resource/33444/40/22191727/53210) note: On Linux it might be required to link SEGGER's `libjlinkarm.so` inside nrfjprog's folder. ## DFU Targets run follow command to install [adafruit-nrfutil](https://github.com/adafruit/Adafruit_nRF52_nrfutil) from PyPi $ pip3 install --user adafruit-nrfutil **make flash** and **make sd** will not work with DFU targets. Hence, **dfu-gen** and **dfu-flash** must be used instead. * dfu-gen: Generates a Firmware zip to be used by the DFU flash application. * dfu-flash: Triggers the DFU flash application to upload the firmware from the generated Firmware zip file. When enabled you have different options to test it: * [NUS Console for Linux](https://github.com/tralamazza/nus_console) (recommended) * [WebBluetooth REPL](https://glennrub.github.io/webbluetooth/micropython/repl/) (experimental)