Time in SCCharts

Alexander Schulz-Rosengarten (1) , Reinhard von Hanxleden (2) , Frédéric Mallet (3, 4) , Robert de Simone (3, 5) , Julien Deantoni (3, 6)

1 CAU - Christian-Albrechts-Universität zu Kiel = Christian-Albrechts University of Kiel = Université Christian-Albrechts de Kiel
2 Department of Computer Science [Kiel]
3 KAIROS - Logical Time for Formal Embedded System Design
4 UniCA - Université Côte d'Azur
5 CRISAM - Inria Sophia Antipolis - Méditerranée
6 COMUE UCA - COMUE Université Côte d'Azur (2015-2019)

Synchronous languages, such as the recently proposed SCCharts language, have been designed for the rigorous specification of real-time systems. Their sound semantics, which build on an abstraction from physical execution time, make these languages appealing, in particular for safety-critical systems. However, they traditionally lack built-in support for physical time. This makes it rather cumbersome to express things like timeouts or periodic executions within the language. We here propose several mechanisms to reconcile the synchronous paradigm with physical time. Specifically, we propose extensions to the SCCharts language to express clocks and execution periods within the model. We draw on several sources, in particular timed automata, the Clock Constraint Specification Language, and the recently proposed concept of dynamic ticks. We illustrate how these extensions can be mapped to the SCChart language core, with minimal requirements on the runtime system, and we argue that the same concepts could be applied to other synchronous languages such as Esterel, Lustre, or SCADE.

Mots clés: Safety-critical systems; Timed automata; Determinism; Multirate timed automata; Synchronous languages; Dynamic ticks; Sequential constructiveness; Clocks; Timing specification; Timing constraints; Clock constraint specification language; Timeouts; Periodic executions; Physical execution time; Multiform notion of time; Time-triggered; Event-triggered; Time-event-triggered; Initialize-update-read protocol; SCCharts; Real-time systems; KIELER; Reactive systems; Model-based engineering

Domaines: Systèmes embarqués

Alexander Schulz-Rosengarten, Reinhard von Hanxleden, Frédéric Mallet, Robert de Simone, Julien Deantoni. Time in SCCharts. Language, Design Methods, and Tools for Electronic System Design, Springer, pp.1-25, 2019, ⟨10.1007/978-3-030-31585-6_1⟩. ⟨hal-02434885⟩