Development Environment Setup on Mac OS

This section describes how to set up a Mac OS development system.

After completing these steps, you will be able to compile and run your Zephyr applications on the following Mac OS 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 was successfully installed, install the following tools using the brew command line.

Install tools to build Zephyr binaries:

$ brew install dfu-util doxygen qemu dtc python3
$ curl -O ''
$ ./
$ rm
$ pip3 install --user -r scripts/requirements.txt

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 the latest version of crosstool-ng (1.23). This version was not available via brew when writing this documentation, you can however try and see if you get 1.23 installed:

$ brew install crosstool-ng

Alternatively you can install the latest version of crosstool-ng from source. Download the latest version from the crosstool-ng site. The latest version usually supports the latest released compilers.

$ wget
$ tar xvf crosstool-ng-1.23.0.tar.bz2
$ cd crosstool-ng-1.23.0/
$ ./configure
$ make
$ make install

Setting Up the Toolchain

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 two configurations for both ARM and X86 that can be used to pre-select 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 menuconfig

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 ZEPHYR_GCC_VARIANT=xtools
$ 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
export ZEPHYR_GCC_VARIANT=xtools