IAR Arm Toolchain

Download and install a release v9.70 or newer of IAR Arm Toolchain on your host (IAR Embedded Workbench or IAR Build Tools, perpetual or subscription licensing)
Make sure you have Zephyr SDK installed on your host.
Set these environment variables:
- Set ZEPHYR_TOOLCHAIN_VARIANT to iar.
- Set IAR_TOOLCHAIN_PATH to the toolchain installation directory.
The cloud licensed variant of the IAR Toolchain needs the IAR_LMS_BEARER_TOKEN environment variable to be set to a valid license bearer token (subscription licensing).

For example:

# Linux (default installation path):
export IAR_TOOLCHAIN_PATH=/opt/iar/cxarm-<version>/arm
export ZEPHYR_TOOLCHAIN_VARIANT=iar
export IAR_LMS_BEARER_TOKEN="<BEARER-TOKEN>"

# Windows:
set IAR_TOOLCHAIN_PATH=c:\<path>\cxarm-<version>\arm
set ZEPHYR_TOOLCHAIN_VARIANT=iar
set IAR_LMS_BEARER_TOKEN="<BEARER-TOKEN>"

Note

Known limitations:

The IAR Toolchain uses ilink for linking and depends on Zephyr’s CMAKE_LINKER_GENERATOR. ilink is incompatible with Zephyr’s linker script template, which works with GNU ld.
The GNU Assembler distributed with the Zephyr SDK is used for .S-files.
C library support for Minimal libc only. C++ is not supported.
Some Zephyr subsystems or modules may contain C or assembly code that relies on GNU intrinsics and have not yet been updated to work fully with iar.
TrustedFirmware is not supported