Cobham Gaisler AB provides IP cores and supporting development tools for embedded processors based on the SPARC architecture. We specialize in digital hardware design for both commercial and aerospace applications

eCos for LEON processors

eCos is an open source, royalty-free, real-time operating system intended for embedded applications. The highly configurable nature of eCos allows the operating system to be customised to precise application requirements, delivering the best possible run-time performance and an optimised hardware resource footprint. Cobham Gaisler has developed and contributed the LEON2 and LEON3 ports of eCos, which include the following functionality:

  • Symmetric multi-processing (SMP) for LEON3
  • Hardware FPU support
  • Network drivers for GRETH, GRETH_GBIT, LAN91C111 and OpenCore's 10/100 Mbit MACs
  • Single-vector trapping (SVT)
  • Non-windowed (flat) register model
  • Possible to run eCos in RAM and ROM

For further information concerning eCos, please refer to the eCos home page.

eCos versions

The LEON port is supported in the eCos-cvs branch. The latest version can be downloaded from our software download page.


eCos is built by the BCC cross-compiler.

How to configure and build a system on linux

Untar the eCos distribution at a suitable location, set the ECOS_REPOSITORY environment variable to the path of the ecos/package directory, eg:

  • export ECOS_REPOSITORY=/home/jiri/ecos/packages

The kernel is built in a seprate directory. To create a leon2 configuration, do:

  • ecosconfig new sparc_leon

A leon3 configuration should be made with:

  • ecosconfig new sparc_leon3

A leon3 configuration with TCP/IP network support and GRETH MAC driver should be made with:

  • ecosconfig new sparc_leon3_greth net

You can then use the eCos configtool to graphically select the eCos parameters and built the system:

  • configtool ecos.ecc


To enable SMP on LEON3 multi-processor systems, you must enable SMP in both the SPARC HAL and the kernel settings.

Refer to the eCos documentation for details on further use.

How to configure and build a system on win32

Use Mingw's MSys enviroment to build ecos and use ecosconfig-mingw.exe instead of ecosconfig.exe

export ECOS_REPOSITORY=c:/ecos/packages
ecosconfig-mingw new sparc_leon3
ecosconfig-mingw tree

The makefile generated by "ecosconfig-ming tree" will transform c:/ to /ecos-c/, therefore add a entry in MSys's /etc/fstab:

c:/ /ecos-c