Transitions as interrupts: a new semantics for timed Statecharts

Statecharts is a visual formalism for the specification of reactive systems. The formalism has been endowed with a step-semantics which heavily bounds the complexity of the reaction in a step, does not model interrupts in a natural way and is not proper for investigating refinement. In this paper, a new model is proposed allowing to overcome the mentioned drawbacks. From a syntactic point of view statecharts are generalized by introducing real time features like delays and timeouts. Though occurrencies of actions are related to a dense time domain, the behaviour of statecharts is forced to be discrete. Classes of statecharts are investigated which intrinsically behave discretely