Importing Atollic C Projects to Eclipse

Eclipse CDT and Cortex M0

1) Get Eclipse CDT; this is an Eclipse IDE tailored to C/C++ development. AFter installing Eclipse CDT, go to “Help”, and “Install New Software”. Add http://gnuarmeclipse.sourceforge.net/updates to the “Work with” path, and select the available update. Install this, and restart Eclipse. Tested on Kepler.

2) Ignore everything you read about CodeLite/CodeSourcery. You want a cross-ARM toolchain that supports newlib-nano, for the size-optimized nano libraries. Specifically, you want “GNU Tools for Embedded Processors (gcc-arm-embedded); download the latest precompiled toolchain (or source, if you are feeling masochistic today) from LaunchPad. It’s maintained by ARM employees so hopefully it isn’t broken. I’ve tested a working binary created on release 2014-q2

Embedded Toolchain Diagram

3) Get a copy of whatever project you’ve successfully developed in Atollic, that you wish to port to this toolchain.

4) Launch Eclipse CDT, and go to “File->Import” to import this project into the workspace.

5) Right click on the project name, and go to “Properties”

• Click on “C/C++ Build”, and note the “Configuration” at the top of the dialog, this is the name of this configuration to which these settings are saved. It is likely “Default [Active]”
• Under “C/C++ Build” on the “Builder Settings” tab, set the Builder Type to “Internal Builder”

6) Under the “C/C++ Build” category, click on “Settings”, then “Toolchains”. Ensure that the name of the toolchain contains a mention of “arm-none-eabi-gcc”

7) Click the “Use Global Toolchain Path”, and navigate to the /bin folder of the toolchain code downloaded and extracted in step 2. For example, “/home/josh/Development/gcc-arm-none-eabi-4_8-2014q2/bin”.

8) Under “Settings” -> “Tool Settings”, set the following:

Target Processor

• ARM family to “cortex-m0”
• Instruction set to “Thumb”

Optimization

• Optimize level “-Os” (optimize size)
• Enable “Function Sections” (-ffunction-sections)
• Enable “Data Sections” (-fdata-sections)

Warnings

• Set “Enable all common warnings (-Wall)”

Debugging

• Set Debug Level to “None”

Cross ARM GNU Assembler

• Under “Preprocessor”, enable “Use Preprocessor” and “Do not search system directories (-nostdinc)”
• Ensure that nothing is listed under the “Includes” path, “Warnings” flags, or “Miscellaneous” flags here

Cross ARM C Compiler

• Under “Preprocessor”, add any symbols that are necessary for your project from Atollic
• Add library paths to the processor-specific header files for the processor which you are building. In the case of the Cortex-MO, this is likely three folders, with names like “/CMSIS/Device/ST/STM32F0xx/Include”, “CMSIS/Include”, and “STM32F0xx_StdPeriph_Driver/inc”
• Add library paths to your own code header files as well
• Under “Optimization”, set the toolchain language to GNU ISO C90

Cross ARM C Linker

• Under “General”, enable “Remove unused sections (-Xlinker -gc-sections)”
• Under “General”, add the script file (which will be executed with “-T”) for your processor. For the STM32, use “stm32_flash.ld”
• Under “Other Linker Flags”, add the following:

-Wl,--start-group -lc -lm -Wl,--end-group -static -Wl,-cref,-u,Reset_Handler

Post Build Commands

The above commands will allow Eclipse to generate an .elf file. To generate a bin or hex, use whatever tool you find most preferable.

Disabling Debug Symbols

• The BlinkyLED project is probably too large (flash overflow) when targetted against an F4. Follow the steps here to disable debug symbols: http://wiki.wxwidgets.org/Eclipse,CDT%26MingW%26_MSYS_Setup_Guide#Changing_the_Build_Configuration

References Operators and C Syntax