Development Environment Setup on macOS

This section describes how to set up a macOS development system.

After completing these steps, you will be able to compile and run your Zephyr applications on the following macOS version:

  • Mac OS X 10.11 (El Capitan)
  • macOS Sierra 10.12

Developing for Zephyr on macOS generally requires you to build the toolchain yourself. However, if there is already an macOS toolchain for your target architecture you can use it directly.

Using a 3rd Party toolchain

If a toolchain is available for the architecture you plan to build for, then you can use it as explained in: Using Custom and 3rd Party Cross Compilers.

An example of an available 3rd party toolchain is GCC ARM Embedded for the Cortex-M family of cores.

Installing Requirements and Dependencies

To install the software components required to build the Zephyr kernel on a Mac, you will need to build a cross compiler for the target devices you wish to build for and install tools that the build system requires.


Minor version updates of the listed required packages might also work.

Before proceeding with the build, ensure your OS is up to date.

First, install the Homebrew (The missing package manager for macOS). Homebrew is a free and open-source software package management system that simplifies the installation of software on Apple’s macOS operating system.

To install Homebrew, visit the Homebrew site and follow the installation instructions on the site.

To complete the Homebrew installation, you might be prompted to install some missing dependency. If so, follow please follow the instructions provided.

After Homebrew is successfully installed, install the following tools using the brew command line.


Zephyr requires Python 3 in order to be built. Since macOS comes bundled only with Python 2, we will need to install Python 3 with Homebrew. After installing it you should have the macOS-bundled Python 2 in /usr/bin/ and the Homebrew-provided Python 3 in /usr/local/bin.

Install tools to build Zephyr binaries:

brew install cmake ninja dfu-util doxygen qemu dtc python3 gperf
cd ~/zephyr   # or to the folder where you cloned the zephyr repo
pip3 install --user -r scripts/requirements.txt


If pip3 does not seem to have been installed correctly use brew reinstall python3 in order to reinstall it.

If you require pyocd, an open source Python 2 library for programming and debugging ARM Cortex-M microcontrollers, use this command to install it using the macOS-bundled Python 2:

pip install --user -r scripts/py2-requirements.txt

If pip for the macOS-bundled Python 2 is not installed, you can install it with:

sudo python -m ensurepip

Source wherever you have cloned the Zephyr Git repository:

cd <zephyr git clone location>

Build Kconfig in $ZEPHYR_BASE/build and add it to path

mkdir build && cd build
cmake $ZEPHYR_BASE/scripts
echo "export PATH=$PWD/kconfig:\$PATH" >> $HOME/.zephyrrc
source $ZEPHYR_BASE/


You only need to do this once after cloning the git repository.

Finally, assuming you are using a 3rd-party toolchain you can try building the Hello World sample to check things out.

To build for the ARM-based Nordic nRF52 Development Kit:

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

# Use cmake to configure a Ninja-based build system:
cmake -GNinja -DBOARD=nrf52_pca10040 ..

# Now run ninja on the generated build system:

Setting Up the Toolchain

Install tools needed for building the toolchain (if needed):

brew install gettext help2man mpfr gmp coreutils wget
brew tap homebrew/dupes
brew install grep --with-default-names

To build the toolchain, you will need crosstool-ng version 1.23 or higher. Install it by using Homebrew:

brew install crosstool-ng

Creating a Case-sensitive File System

Building the compiler requires a case-sensitive file system. Therefore, use diskutil to create an 8 GB blank sparse image making sure you select case-sensitive file system (OS X Extended (Case-sensitive, Journaled) and mount it.

Alternatively you can use the script below to create the image:

diskutil umount force /Volumes/${ImageName} && true
rm -f ${ImageNameExt} && true
hdiutil create ${ImageName} -volname ${ImageName} -type SPARSE -size 8g -fs HFSX
hdiutil mount ${ImageNameExt}
cd /Volumes/$ImageName

When mounted, the file system of the image will be available under /Volumes. Change to the mounted directory:

cd /Volumes/CrossToolNG
mkdir build
cd build

Setting the Toolchain Options

In the Zephyr kernel source tree we provide configurations for NIOS-II and X86 that can be used to preselect the options needed for building the toolchain.

The configuration files can be found in $ZEPHYR_BASE/scripts/cross_compiler/.

Currently the following configurations are provided:

  • i586.config: for standard ABI, for example for Galileo and qemu_x86
  • iamcu.config: for IAMCU ABI, for example for the Arduino 101
  • nios2.config: for Nios II boards
cp ${ZEPHYR_BASE}/scripts/cross_compiler/i586.config .config

You can create a toolchain configuration or customize an existing configuration yourself using the configuration menus:

export CT_PREFIX=/Volumes/CrossToolNG
ct-ng oldconfig

Verifying the Configuration of the Toolchain

Before building the toolchain it is advisable to perform a quick verification of the configuration set for the toolchain.

  1. Open the generated .config file.
  2. Verify the following lines are present, assuming the sparse image was mounted under /Volumes/CrossToolNG:
# CT_SAVE_TARBALLS is not set
# Following options prevent link errors

Building the Toolchain

To build the toolchain, enter:

ct-ng build

The above process takes a while. When finished, the toolchain will be available under /Volumes/CrossToolNG/x-tools.

Repeat the step for all architectures you want to support in your environment.

To use the toolchain with Zephyr, export the following environment variables and use the target location where the toolchain was installed, type:

export XTOOLS_TOOLCHAIN_PATH=/Volumes/CrossToolNG/x-tools

To use the same toolchain in new sessions in the future you can set the variables in the file $HOME/.zephyrrc, for example:

cat <<EOF > ~/.zephyrrc
export XTOOLS_TOOLCHAIN_PATH=/Volumes/CrossToolNG/x-tools