Asynchronous-Channels Within Petri Net-Based GALS Distributed Embedded Systems Modeling

Model-based development approaches can provide a major contribution in the development of globally asynchronous locally synchronous distributed embedded systems (GALS-DES) if supported by suited modeling formalisms and design automation tools. The use of Petri nets (either low-level or high-level classes) extended with asynchronous-channels (ACs), time domains, priorities, inputs, and outputs is proposed in this paper to model GALS-DES (composed by deterministic components), ensuring that the created GALS model is locally deterministic, distributable, network-independent, and platform-independent. The proposed ACs, with high level of abstraction, specify the components interaction through Petri net objects with specific attributes that unambiguously identify this interaction within the GALS model. Two algorithms are proposed to translate and decompose the GALS model into Petri net models without ACs, which can be used as inputs in model-checking tools and automatic code generators supporting GALS-DES verification and implementation. The specification of a small goods lift distributed controller illustrates the use of the proposed ACs.