Research On Petri Net Based High Level Designing Method And Technology For Embedded Systems

In recent years, Embedded systems developed very fast and played an important role in almost all aspects of our daily lives. The related technology is becoming one of the crucial research areas in computer science and applications. The traditional method and technology are not suitable for designing large scales complex embedded systems, which are very popular in real world nowadays. Developing high level designing method and technology for embedded systems turned into a challenge for every designer. In this dissertation, the existing methods and techniques were reviewed considering the characteristics of embedded systems. A novel high level methods and techniques to design embedded systems were proposed based on a kind of extended Petri Net models, which was object oriented, timed and dual flow models. The techniques of modeling and verifying embedded system were studied. The design flow and pattern for embedded systems were discussed under the PN model. The methods and techniques are proved feasible and practical through designing an example of embedded system.The main work of this dissertation are listed as follows:The developing course of embedded systems was briefly traced and the problems in design methodology were put forward then. The existing high-level models of embedded systems are reviewed and a conclusion was drawn that executable formal models are best choice for embedded systems.Traditional Petri nets lack the data processing abilities and hierarchical structures. It could not model time-constrained systems as well. Therefore, an object oriented, timed and dual flow Petri net (OO-TDPN) was proposed and formally defined. The port and open net conceptions were introduced to OO-TDPN models in order to boost up its interaction abilities. OO-TDPN is more suitable to model time constrained, complex embedded systems versus other ones.Some techniques to verifying PN models were studied, including simulation and model checking. The principles of both techniques were specified. The circuit implementation of Petri net provided an effective way to analyze PN models. The techniques to implement OO-TDPN with Verilog hardware description language were discussed in details. The simulation results indicated that circuit simulation method was feasible and practical. The circuit implementation of Petri net is easy to realize, better applicability and easy to synthesis compared with software tools.The design flow of embedded systems was studied and a design flow was recommended based on PN models. According to the design flow, two examples—embedded IDS (intrusion detect system) and elevator controller were designed. Taking the characteristics of embedded system into account, high level designing method and technology were remarked. The conclusions were drawn that the above method and technology could match the embedded system requests successfully.Finally, the main achievements of this dissertation were summarized and the further research was stated briefly.