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C++17 framework for Nordic nRF5 microcontrollers

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NRFCXX is a build environment and development framework for Nordic nRF5 Cortex®-M microcontrollers using C++.

Characteristics of this framework include:

  • Requires C++17 or later;
  • Designed for ultra-low-power wireless sensor applications using Bluetooth beacon technology;
  • Supports both nRF51 and nRF52 processors;
  • Implemented for use with GNU Compiler;
  • Uses the [nrfx][] mdk CMSIS headers with C++ templates for optimized control through peripheral registers without HAL or other intervening driver API;
  • Provides an event-driven control model with state machine infrastructure for sensors;
  • Leverages Nordic soft devices for Bluetooth 4.2 (nRF51) and 5.0 (nRF52) compatibility;
  • Full API documentation;
  • Multiple examples;
  • Support for multiple easily obtained nRF5-based development boards.

Characteristics the framework currently lacks:

  • Support for Bluetooth peripheral and central roles;
  • Support for OTA firmware update;
  • Detailed high-level documentation and a roadmap through examples;
  • Ability to build applications out-of-tree;
  • Script support on non-POSIX systems.

Source code and issue management are at:

Documentation is at:

Build Area Setup

NRFCXX uses the Meson build system for build management. There are subprojects, so start with:

meson subprojects download

You also must download and patch the Nordic soft devices; see instructions in the softdevice subdirectory.

Each build area is configured for a specific target board, or by default for the host to build documentation and run unit tests. In-tree boards are provided in the board subdirectory, and can be selected like this:

scripts/mkbuild pca10056

which will configure the pca10056 directory to build for the nRF52840-DK. The libraries and all example applications can then be built with:

ninja -C pca10056

Applications that do not require soft devices can be programmed onto the board with the nRF5 Command Line Tools:

ELF=examples/bootstrap/devinfo ninja -C pca10056 program

Host-based test suite

When the --cross option is not used to configure the build area a subset of the framework is built for host-based unit testing. You may also set board.

Consider adding -Db_coverage=true when configuring a host build area. This allows:

ninja -C build test
ninja -C build coverage-html

The coverage results will be in build/meson-logs/coveragereport/.

Controlling Dev Boards

Several run targets are provided that can be accessed as ninja commands. If there is only one JLink device on the system the board attached to that device will be programmed.

If multiple JLink devices are present the serial number of the desired device should be set in the JSN environment variable. Otherwise the device with the lowest serial number will be used.

At meson 0.45 presenting multiple commands works and they are executed in the order specified in the script (not necessarily command-line order).


JSN=681982376 ninja erase
ELF=examples/s130/sd-beacon ninja erase flash_softdevice program


This command invokes the --eraseall nrfjprog action.


This command looks in the ELF environment variable for a path, relative to the build root, to an elf file that should be programmed. The .elf suffix present on the constructed images will be added if necessary. It then converts the image to Intel hex in a temporary file, programs it with the nrfjprog --program action and --sectorerase, then resets the board with the nrfjprog --reset action.


ELF=examples/bootstrap/alarm ninja program


This command flashes the soft device onto the board. It neither erases nor resets.


This command issues a hard reset to the board.