This repository provides support for bare-metal programming of nRF52 boards from Nordic Semiconductor using Lingua Franca (LF). Note that Nordic has shifted its focus to Zephyr, so you might consider using the Zephyr platform instead of bare metal programming.
There is quie a bit of work remaining to do:
- Merge the nrf52 branch into lingua-franca and update instructions below.
- Makefiles currently do not tolerate path names with spaces.
- Support SDK versions 16 and 17 (currently only 15 has been tested).
- Support turning off soft device (in reactor-c, find "FIXME: If softdevice is not enabled").
- Extend NRF52 target to support a
boardargument and handle switching boards. - Support nRF53 devices with threaded runtime to use both cores.
git clone git@github.com:lf-lang/lf-nRF52.git
cd lf-nRF52
git submodule update --init --recursive
Until the NRF52 support is included in an LF release, you will need to use the lingua-franca git repository instead of a release of Lingua Franca:
git clone git@github.com:lf-lang/lingua-franca.git
cd lingua-franca
git switch nrf52
git submodule update --init --recursive
There is an executable program lfc-dev in lingua-franca/bin that you can use to compile .lf programs using this branch of the Lingua Franca compiler. We suggest putting the directory lingua-franca/bin in your path.
Install the gcc-arm-none-eabi toolchain.
On MacOS:
brew install --cask gcc-arm-embedded
On Ubuntu (the following is probably out of date):
cd /tmp \
&& wget -c https://developer.arm.com/-/media/Files/downloads/gnu-rm/9-2020q2/gcc-arm-none-eabi-9-2020-q2-update-x86_64-linux.tar.bz2 \
&& tar xjf gcc-arm-none-eabi-9-2020-q2-update-x86_64-linux.tar.bz2 \
&& sudo mv gcc-arm-none-eabi-9-2020-q2-update /opt/gcc-arm-none-eabi-9-2020-q2-update \
&& rm gcc-arm-none-eabi-9-2020-q2-update-x86_64-linux.tar.bz2 \
&& sudo ln -s /opt/gcc-arm-none-eabi-9-2020-q2-update/bin/* /usr/local/bin/.
Install the JLink software for your platform. You want the "Software and documentation pack". As of April 2020, some of the more recent JLink software is unstable on Linux. Version 6.34b has been verified to work reliably on Linux and MacOS.
Once you have followed the Setup instructions above, assuming you have an nRF52840dk board, compile the Simplest.lf file as follows:
cd lf-nRF52
lfc-dev src/Simplest.lf
If your board is plugged in to a USB port, this should automatically flash the program onto the board and cause LED number 1 to start blinking.
Other sample programs are provided in the src directory.
There are also some simple C programs that have no dependencies on Lingua Franca. If the above doesn't work, these can be useful to track down why. Assuming you are in the lf-nRF52 root directory, try the following:
cd nrf52x-base/apps/basic/blink
make flash
This simple C program flashes an LED. The button program in the same directory should also work.
The repository and demo programs are configured by default to assume that you are using the nRF52840dk board with soft device s140. Specifically, the file platform/Makefile has the following lines:
# Configurations
NRF_IC = nrf52840
SDK_VERSION = 15
SOFTDEVICE_MODEL = s140
It may work to change the NRF_IC to, for example, nrf52832, but this has not been tested. You will also need to change the SOFTDEVICE_MODEL to, for example, s132. More likely, you will need to make more changes.
To change boards, copy the appropriate Board.mk file from nrf52x-base/boards/... into the platforms directory, overwriting the file that is there.
The file platform/Makefile pulls in the platform/Board.mk and Nordic's master makefile, nrf52x-base/make/AppMakefile.mk. To customize, you can define makefile variables by editing platform/Makefile and setting the variables described in Nordic's README file, nrf52x-base/make/README.md (available after doing git submodule update --init --recursive).
Assuming USE_APP_CONFIG is set (as it is by default in platform/Makefile), Nordic's AppMakefile.mk will cause the platform/app_config.h to be included with your sources. That file is a copy of the app_config.h file in the nrf52x-base/boards/nrf52840dk/ directory, modified by adding the following line:
#define TIMER3_ENABLED 1
This line is needed because the Lingua Franca runtime uses timer 3 for its timer functionality.
A soft device is a Nordic concept that provides a layer of abstraction between your application and the underlying device drivers. It is needed to enable bluetooth communication with the board. If you wish to run your code on truly bare metal, with no soft device, you can change the SOFTDEVICE_MODEL to blank, but you will also have to make a small change in the lfc-dev compiler. Specifically, the file lf_nrf52_support.c has the following lines:
return sd_nvic_critical_region_exit(0);
// FIXME: If softdevice is not enabled, do the following instead of above:
// __enable_irq();
// return 0;
...
return sd_nvic_critical_region_enter(&success);
// FIXME: If softdevice is not enabled, do the following instead of the above:
// __disable_irq();
// return 0;
In each of these two blocks, you will need to comment out the first line and uncomment the last two.
A suite of nRF command-line tools may prove useful.
This will install tools like nrfjprog and mergehex, as well as the optional python bindings for nrfjprog, pynrfjprog.
For example, you can use these tools to erase the device:
nrfjprog --eraseall
You can also flash a hex file:
cd nRF5_SDK_17.1.0_ddde560/examples/ble_peripheral/ble_app_hrs/hex
nrfjprog --reset --program ble_app_hrs_pca10056_s140.hex --verify
- The LF compiler puts source files in directories called
src-genandinclude(andfed-genfor federated programs). If you get compiler or linker errors that are unexpected, try deleting these directories.