GNU Arm Embedded
- Download and install a GNU Arm Embedded build for your operating system and extract it on your file system. - Note - On Windows, we’ll assume for this guide that you install into the directory - C:\gnu_arm_embedded. You can also choose the default installation path used by the ARM GCC installer, in which case you will need to adjust the path accordingly in the guide below.- Warning - On macOS Catalina or later you might need to change a security policy for the toolchain to be able to run from the terminal. 
- Set these environment variables: - Set - ZEPHYR_TOOLCHAIN_VARIANTto- gnuarmemb.
- Set - GNUARMEMB_TOOLCHAIN_PATHto the toolchain installation directory.
 
- To check that you have set these variables correctly in your current environment, follow these example shell sessions (the - GNUARMEMB_TOOLCHAIN_PATHvalues may be different on your system):- # Linux, macOS: $ echo $ZEPHYR_TOOLCHAIN_VARIANT gnuarmemb $ echo $GNUARMEMB_TOOLCHAIN_PATH /home/you/Downloads/gnu_arm_embedded # Windows: > echo %ZEPHYR_TOOLCHAIN_VARIANT% gnuarmemb > echo %GNUARMEMB_TOOLCHAIN_PATH% C:\gnu_arm_embedded - Warning - On macOS, if you are having trouble with the suggested procedure, there is an unofficial package on brew that might help you. Run - brew install gcc-arm-embeddedand configure the variables- Set - ZEPHYR_TOOLCHAIN_VARIANTto- gnuarmemb.
- Set - GNUARMEMB_TOOLCHAIN_PATHto the brew installation directory (something like- /usr/local)