Building and Running an Application

Congratulations! You have successfully set up your development environment and created a Zephyr application. This section provides all the steps to build a Zephyr kernel containing your application and run it. We use the Hello World sample application as an example. However, the steps needed are the same for your own application.

The processes to build and run a Zephyr application are the same across operating systems. Nevertheless, the commands needed do differ from one OS to the next. The following sections contain the commands used in a Linux development environment. If you are using Mac OS please use the appropriate commands for your OS.

Building a Sample Application

To build an example application follow these steps:

  1. Go to the root directory of the Zephyr Project.

  2. Set the environment variables on each console, see Setting the Project’s Environment Variables

  3. Build the example project, enter:

    $ cd $ZEPHYR_BASE/samples/hello_world/microkernel

$ make

The above invocation of make will build the hello_world sample application using the default settings defined in the application’s Makefile. You can build for a different platform by defining the variable BOARD with one of the supported platforms, for example:

$ make BOARD=minnowboard

For further information on the supported platforms go see here. Alternatively, run the following command on the code root to obtain a list of the supported platforms of a particular architecture:

$ make help

The sample projects for the microkernel and the nanokernel are found at $ZEPHYR_BASE/samples/microkernel/apps and $ZEPHYR_BASE/samples/nanokernel/apps respectively. After building an application successfully, the results can be found in the outdir sub-directory under the application root directory.

The ELF binaries generated by the build system are named by default zephyr.elf. This value can be overridden in the Makefile. The build system generates different names for different use cases depending on the hardware and platforms used.

Running a Sample Application

To perform rapid testing of an application in the development environment you can use QEMU with some of the supported platforms and architecture. This can be easily accomplished by calling a special target when building an application that invokes QEMU once the build process is completed.

  1. Run an application using the default board configuration, type:

    $ make qemu

To run an application using the x86 emulation board configuration (qemu_x86), type:

$ make BOARD=qemu_x86 qemu

To run an application using the ARM qemu_cortex_m3 board configuration, type:

$ make BOARD=qemu_cortex_m3 ARCH=arm qemu

QEMU is not supported on all boards and platforms. Some samples and test cases might fail when running in the emulator. When developing for a specific hardware target you should always test on the actual hardware and should not rely on testing in the QEMU emulation environment only.