Getting Started Guide¶

Use this guide to get started with your Zephyr development.

Checking Out the Source Code Anonymously¶

The Zephyr source code is hosted in a GitHub repo that supports anonymous cloning via git. There are scripts and such in this repo that you’ll need to set up your development environment, and we’ll be using Git to get this repo. (If you don’t have Git installed, see the beginning of the OS-specific instructions below for help.)

We’ll begin by using Git to clone the repository anonymously. Enter:

# On Linux/macOS
cd ~
# On Windows
cd %userprofile%

git clone https://github.com/zephyrproject-rtos/zephyr.git

You have successfully checked out a copy of the source code to your local machine in a zephyr folder in your home directory.

A brief note on the Zephyr build system¶

The Zephyr project uses CMake as a tool for managing the building of the project. CMake is able to generate build files in different formats (also known as “generators”), and the following ones are currently supported by Zephyr:

make: Supported on UNIX-like platforms (Linux, macOS).

ninja: Supported on all platforms.

Most of the examples in the Zephyr documentation use ninja as a build tool, but you should be able to use any generator on any of the examples listed.

Set Up the Development Environment¶

The Zephyr project supports these operating systems:

Linux
macOS
Microsoft Windows

Use the following procedures to create a new development environment.

Building and Running an Application¶

Next, build a sample Zephyr application. You can then run it either in emulation or using POSIX APIs available on your host.

If your board is supported by Zephyr (see Supported Boards for a list), consult its documentation for flashing and running instructions.

Building a Sample Application¶

Follow these steps to build the Hello World sample application provided with Zephyr.

Navigate to the main project directory:
```
cd zephyr
```

Set up your build environment:

# On Linux/macOS
source zephyr-env.sh
# On Windows
zephyr-env.cmd

Build the Hello World example for the arduino_101 board, enter:

# On Linux/macOS
cd $ZEPHYR_BASE/samples/hello_world
mkdir -p build/arduino_101 && cd build/arduino_101

# On Windows
cd %ZEPHYR_BASE%\samples\hello_world
mkdir build\arduino_101 & cd build\arduino_101


# Use cmake to configure a Ninja-based build system:
cmake -GNinja -DBOARD=arduino_101 ../..

# Now run ninja on the generated build system:
ninja

On Linux/macOS you can also build with make instead of ninja:

cd $ZEPHYR_BASE/samples/hello_world
mkdir -p build/arduino_101 && cd build/arduino_101

# Use cmake to configure a Make-based build system:
cmake -DBOARD=arduino_101 ../..

# Now run make on the generated build system:
make

You can build for a different board by defining the variable BOARD with another of the supported boards, for example:

# On Linux/macOS
cd $ZEPHYR_BASE/samples/hello_world
mkdir -p build/arduino_due && cd build/arduino_due

# On Windows
cd %ZEPHYR_BASE%\samples\hello_world
mkdir build\arduino_due & cd build\arduino_due


# Use cmake to configure a Ninja-based build system:
cmake -GNinja -DBOARD=arduino_due ../..

# Now run ninja on the generated build system:
ninja

For further information on the supported boards go see here. Alternatively, run the following command to obtain a list of the supported boards:

ninja usage

Sample projects for different features of the project are available at at ZEPHYR_BASE/samples. After building an application successfully, the results can be found in the directory where cmake was invoked.

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

Building without the Zephyr SDK¶

The Zephyr SDK is provided for convenience and ease of use. It provides cross-compilers for all ports supported by the Zephyr OS and does not require any extra flags when building applications or running tests. In addition to cross-compilers, the Zephyr SDK also provides prebuilt host tools.

It is, however, possible to build without the SDK. If you are using 3rd party cross compilers, jump forward to Using 3rd Party Cross Compilers for details. A “3rd party cross compiler” is a toolchain that the Zephyr build system already knows about, such as GNU ARM Embedded that we use in this document.

If you are going to use custom compilers, check Using Custom Cross Compilers for more detail. A “custom compiler” would be the one your Linux distribution packaged, the one you compiled on your own, or the one you downloaded from the net. The Zephyr build system doesn’t know about them and doesn’t officially support them.

As already noted above, the SDK also includes prebuilt host tools. To use the SDK’s prebuilt host tools alongside a 3rd party or custom cross-compiler, keep the ZEPHYR_SDK_INSTALL_DIR environment variable set to the Zephyr SDK installation directory. To build without the Zephyr SDK’s prebuilt host tools, the ZEPHYR_SDK_INSTALL_DIR environment variable must be unset

Follow the steps below to build without the Zephyr SDK:

# On Linux/macOS
unset ZEPHYR_SDK_INSTALL_DIR
cd <zephyr git clone location>
source zephyr-env.sh
# On Windows
set ZEPHYR_SDK_INSTALL_DIR=
cd <zephyr git clone location>
zephyr-env.cmd

Using 3rd Party Cross Compilers¶

To use a 3rd party cross compiler that is not provided by the Zephyr SDK, follow the steps below.

We will use the GNU ARM Embedded compiler for this example, download the package suitable for your operating system from the GNU ARM Embedded website and extract it on your file system. This example assumes the compiler was extracted to: <user folder>/gcc-arm-none-eabi-7-2018-q2-update/.

Build the example Hello World project, enter:

# On Linux/macOS
export GNUARMEMB_TOOLCHAIN_PATH="~/gcc-arm-none-eabi-7-2018-q2-update/"
export ZEPHYR_TOOLCHAIN_VARIANT=gnuarmemb
# On Windows
set GNUARMEMB_TOOLCHAIN_PATH="%userprofile%\gcc-arm-none-eabi-7-2018-q2-update\"
set ZEPHYR_TOOLCHAIN_VARIANT=gnuarmemb

# On Linux/macOS
cd $ZEPHYR_BASE/samples/hello_world
mkdir build && cd build

# On Windows
cd %ZEPHYR_BASE%\samples\hello_world
mkdir build & cd build


# Use cmake to configure a Ninja-based build system:
cmake -GNinja -DBOARD=arduino_due ..

# Now run ninja on the generated build system:
ninja

Make sure to unset the ZEPHYR_SDK_INSTALL_DIR if you don’t use the SDK’s host tools. See Building without the Zephyr SDK for details.

It is possible to use the Zephyr SDK’s host tools along with a 3rd party cross compiler. To do that, keep the ZEPHYR_SDK_INSTALL_DIR environment variable set to the Zephyr SDK installation directory. See Set Up the Development Environment for more details on the ZEPHYR_SDK_INSTALL_DIR environment variable.

Using Custom Cross Compilers¶

To use a custom cross compiler, follow the steps below.

Install a cross compiler suitable for your system. We will use the gcc-arm-none-eabi compiler on Debian system for this example.

# On Debian or Ubuntu
sudo apt-get install gcc-arm-none-eabi
# On Fedora or Red hat
sudo dnf install arm-none-eabi-newlib

Build the example Hello World project, enter:

# On Linux
unset GNUARMEMB_TOOLCHAIN_PATH
export ZEPHYR_TOOLCHAIN_VARIANT=cross-compile
export CROSS_COMPILE=/usr/bin/arm-none-eabi-

# On Linux/macOS
cd $ZEPHYR_BASE/samples/hello_world
mkdir build && cd build

# On Windows
cd %ZEPHYR_BASE%\samples\hello_world
mkdir build & cd build


# Use cmake to configure a Ninja-based build system:
cmake -GNinja -DBOARD=arduino_zero ..

# Now run ninja on the generated build system:
ninja

Note that the Zephyr build system assumes that all the tools within your toolchain used to compile and link your code, reside in the same directory and have a common prefix. Set the CROSS_COMPILE environment variable to the path of your toolchain’s location and that common prefix. In the example above, gcc-arm-none-eabi is installed in /usr/bin/ with the common prefix of arm-none-eabi-. If your toolchain is at /opt/mytoolchain/bin with the prefix of myarch-none-elf-, it would be CROSS_COMPILE=/opt/mytoolchain/bin/arch-none-elf-.

Make sure to unset the ZEPHYR_SDK_INSTALL_DIR if you don’t use the SDK’s host tools. See Building without the Zephyr SDK and Set Up the Development Environment for more details.

Running a Sample Application in QEMU¶

To perform rapid testing of an application in the development environment you can use the QEMU emulation board configuration available for both X86 and ARM Cortex-M3 architectures. This can be easily accomplished by calling a special target when building an application that invokes QEMU once the build process is completed.

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

cd $ZEPHYR_BASE/samples/hello_world
mkdir build && cd build

# Use cmake to configure a Ninja-based build system:
cmake -GNinja -DBOARD=qemu_x86 ..

# Now run ninja on the generated build system:
ninja
ninja run

To exit the qemu emulator, press Ctrl-a, followed by x.

Use the qemu_cortex_m3 board configuration to test the ARM build.

QEMU is not supported on all boards and SoCs. 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.

Running a Sample Application natively (POSIX OS)¶

It is also possible to compile some of the sample and test applications to run as native process on a POSIX OS (e.g. Linux). To be able to do this, remember to have installed the 32 bit libC if your OS is natively 64bit. See the Native POSIX execution (native_posix) section on host dependencies for more information.

To compile and run an application in this way, type:

cd $ZEPHYR_BASE/samples/hello_world
mkdir build && cd build

# Use cmake to configure a Ninja-based build system:
cmake -GNinja -DBOARD=native_posix ..

# Now run ninja on the generated build system:
ninja

and then:

ninja run

# or just:
zephyr/zephyr.exe
# Press Ctrl+C to exit

You can run zephyr/zephyr.exe --help to get a list of available options. See the Native POSIX execution (native_posix) document for more information.

This executable can be instrumented like any other Linux process. For ex. with gdb or valgrind. Note that the native port is currently only tested in Linux.