How to port projects from IAR EWARM to SEGGER Embedded Studio

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This wiki article describes how to import IAR EWARM projects into SEGGER Embedded Studio using the build in project importer. With the project importer you can either keep using the IAR compiler inside Embedded Studio or
use the GCC/Clang compiler that is used inside Embedded Studio. By switching your project to Embedded Studio you can directly benefit from features like multi-threaded compiling, fast and simple project search, indexing and more.
Many features are even available should you still decide to be using the IAR compiler inside Embedded Studio. A full feature list can be found here.


The following import tutorial will be based on the following Hardware and Software combinations:

  • SEGGER Embedded Studio 3.12 64-bit (Project importer works on 3.10 or later)
  • IAR EWARM 7.80
  • Target Evalboard: SEGGER emPower

The following file contains the example project for you to try out:

Import tutorial

  • Open your copy of Embedded Studio and go to File -> Import IAR EWARM / Keil MDK Project... then navigate to the project file you want to import and select it.
IAR Example Project Folder
  • Now you will have the opportunity to choose between:
    • External Toolchain: imports the project and configures it to be built with the original toolchain.
    • Internal Toolchain: imports the project and sets the configuration for the Embedded Studio tool chain.
    • Internal and External Toolchains: creates a set of build configurations to build with the original tool chain and one set to build with the Embedded Studio tool chain.
    • "IAR Installation Directory" where you get the option to use a different external IAR compiler if you have multiple IAR EWARM versions installed.
  • To migrate to Embedded Studio it is recommended to create build configurations for internal and external tool chains so you can easily switch between the tool chains later on.
Project importer options
  • If everything worked out well the following status window should pop up:
Successful import
  • Embedded Studio will automatically create build configurations for debug and release versions with the internal and external compiler that have been present in the existing IAR project.
  • To switch between them the drop down menu in the "Project Explorer" can be used.
Build configurations window
  • To debug the example project with the IAR compiler choose "Debug_External" in the drop down menu and build the project by pressing F7.
  • For most projects this will work out of the box, if it does not build out of the box please refer to section "Troubleshooting".

How to switch to internal Embedded Studio compiler

  • To use the full potential of Embedded Studio it is required to use the internal compiler which is based on GCC/Clang.
  • This can be done in the provided example project by simply going to the drop down menu and select "Debug_Internal".
  • The project will now be built when pressing F7 with the internal GCC compiler by default. Clang can be enabled in the project options instead.
  • After a successful build with the internal compiler Embedded Studio will automatically calculate how much flash and RAM will be occupied on your target device and represent it visually in the output window.
Code flash and RAM usage
  • Note: this feature is only available when using the internal compilers.
  • For most projects switching to the internal compiler work out of the box, if it does not build out of the box please refer to section "Troubleshooting".


While imported projects will usually re-build with the external tool chain out-of-the-box, for GCC/Clang based project build configurations, some manual changes may be required.

In some cases the sources are created to be GCC compatible, then you can seamlessly switch between original tool chain and GCC. When the original project is created from a software pack or SDK, it might already come with GCC compatible source files which can replace the former tool chain compatible files.

The following points list the most common changes which are required to migrate a project to Embedded Studio.

Memory Linker Script

The Embedded Studio project importer does not import linker scripts (e.g. IAR icf files). It sets up the basic memory map for the selected target device, which will put code into the internal flash and data into the internal SRAM.

For more advanced or different configurations, the memory map file and the section placement file have to be set up accordingly.

To place memory segments there are two options available in Embedded Studio:

  1. Place segments directly via project options under "Linker -> Section Placement Segments"
  2. Create a memory map .xml file or edit the default file provided by Embedded Studio and set it in project options under "Linker -> Use Manual Linker Script"

For example, a memory-map file representing a device with two memory segments called FLASH and SRAM could look something like this in the memory-map editor.

<Root name="Device1">
  <MemorySegment name="FLASH" start="0x10000000" size="0x10000" />
  <MemorySegment name="SRAM"  start="0x20000000" size="0x1000" />

A corresponding section-placement file will refer to the memory segments of the memory-map file and will list the sections to be placed in those segments. This is done by using a memory-segment name in the section-placement file that matches the corresponding memory-segment name in the memory-map file.

For example, a section-placement file that places a section called .stack in the SRAM segment and the .vectors and .text sections in the FLASH segment would look like this:

<Root name="Flash Section Placement">
  <MemorySegment name="FLASH" >
    <ProgramSection name=".vectors" load="Yes" />
    <ProgramSection name=".text" load="Yes" />
  <MemorySegment name="SRAM" >
   <ProgramSection name=".stack" load="No" />

To add new segments or sections simply edit the default file linked by Embedded Studio. The linked file can be found in the project options under "Linker -> Section Placement File".

More information about how to setup such files can be found in the Embedded Studio Help window in chapter "Linking and section placement".

Third Party Software and Libraries

Third party software, especially libraries, might be configured for one tool chain and do not compile with other tool chains.

Check if there is a port of the software for Embedded Studio / GCC or configure and rebuild the software for Embedded Studio / GCC.

Although libraries built for another tool chain may link with Embedded Studio, always take care and check that interfacing with the library works as expected.

Assembly Code

The syntax of assembler code and control commands in assembler files can be different across tool chains.

Although the resulting assembled instructions are identical, the assembler code to be written can be different across tool chains, for example numerical constants need to be declared differently for IAR and GCC/Clang.

Control commands which help writing assembler code is different, too. The syntax for symbols, labels, function definitions, and alike needs to be adjusted to work with the GNU assembler.

The following table shows some "popular" assembler directives that can be substituted by the corresponding conjugate:

IAR assembler directive GCC/Clang assembler directive
PUBLIC .global
SECTION .section
MACRO .macro
ENDM .endm
THUMB .thumb_func
END .end
EXTERN .extern
DC32 .word

For a complete list please refer to the corresponding assembler reference manuals.

Preprocessor Defines

Tool chains use different built-in definitions to identify the compiler which is used and to allow conditional compilation based on the configuration of core, device, endianess, and other settings.

It is mandatory to choose the correct definitions and recommended to make sure the code throws a warning or error when required definitions are not defined.

IAR defines __ICCARM__ and __IAR_SYSTEMS_ICC__ which can be used for identification, Embedded Studio defines __SES_ARM and __GNUC__.

For the target device IAR defines __ARM7M__ and __CORE__=__ARM7M__ when compiling for Cortex-M4, Embedded Studio uses __ARM_ARCH_7M__ instead.

Tool Chain Intrinsics

Compiler-specific functions like __disable_interrupt() or __no_operation() might not be available in Embedded Studio. Write corresponding replacement functions or avoid using them at all.

A replacement function for __no_operation() could look like this for GCC/Clang:

#define NO_OPERATION() __asm volatile ("nop")

To make it backwards compatible with IAR such a redefinition can be nested within preprocessor defines; __ICCARM__ for IAR EWARM and __SES_ARM for Embedded Studio.

Project Settings

Most project settings are set automatically by the project importer for the external and internal build configuration. In some more complex projects certain project settings need to be added manually.

For example by default no files are excluded from the internal build configuration, so if there is a compiler incompatible file the compiler will try to compile it and show errors (e.g. GCC/Clang incompatible assembler files).

To do this right click your project in the project explorer and select "Edit options". More information about the individual settings can be found in the Embedded Studio user manual.

User Included Directories

Many more complex projects link their sources from multiple folders in different paths. Make sure all needed folders are included in the build configuration under "Preprocessor -> User Include Directories".

Pre/Post Build Commands

Embedded Studio offers the possibility to use pre/post build commands familiar to the ones in IAR EWARM. However the project importer does not import these as the syntax between IAR and Embedded studio differs.

Should you be using such commands in IAR make sure you mimic them in Embedded Studio in the internal and external build configurations accordingly .

To execute multiple commands at once the use of a batch script is possible.

For example to enable a post link batch script go into the project options for the intended build config, go to "User Build Step" and edit the entry "Post-Link Command".

Now enter the relative or absolute path of the bat file and the optional parameters: Path/Example.bat Param1 Param2 ...