Graphical design of embedded control system software based on SDL/RealTime with special support for safety critical applications

Time and market pressure enforce a fast, flexible, safe and comfortable design of embedded control system software. The visualisation of the design process, i.e. graphical design capture, automatic translation and full functional and timing simulation of the target system in a workstation environment, allows to achieve these goals. This paper describes a system design methodology for embedded control systems based on a subset of ITU-T SDL, a language for specification and description of systems. While SDL is well suitable for the design of distributed heterogeneous systems we propose an extension to the subset, SDL/RealTime, which supports especially the graphical design of timing and safety critical embedded control systems with extensive local inter process communication. A timing concept will be introduced which is essential to embedded control applications. We decided to combine specification, targeting and timing aspects into one language to enable an integrated design flow. The article introduces SDL/RealTime and discusses the tool environment for design capture, automatic translation and run time support.