The Definition of Extended High-level Timed Petri Nets

Many extensions of Petri nets have been proposed to model the behaviors and time relations of embedded system, yet these models are all based on some assumptions about the behaviors of embedded systems. Especially they all do not have the actual ability to model interrupt mechanism of embedded system. A new net which is called Extended High Level Timed Petri Nets (EHLTPN) is introduced in this study. It shows how to extend High Level Petri Nets (HLPN) with time, actions and interrupt mechanism. Interruptible subnets corresponding to different interruptible resources are introduced to model the behaviors and time relations of distributed embedded real-time systems. Each interruptible subnet realizes interrupt mechanism by an Interrupt Switch Transition and a set of Resuming Transitions. We give an informal description of this new model and show how this model be formally defined. A transform rule presented shows that each subnet corresponding to an interruptible resource in EHLTPN can be transformed into a behaviorally equivalent subnet of HLTPNAT with priority. This model makes it possible to create the compact and comprehensive models for distributed embedded real-time systems.