An alternative polychronous model and synthesis methodology for model-driven embedded software

Abstract

Multi-clocked synchronous (a.k.a. Polychronous) specification languages do not assume that execution proceeds by sampling inputs at predetermined global synchronization points. The software synthesized from such specifications are paced by arrival of certain inputs, or evaluation of certain internal variables. Here, we present an alternate polychronous model of computation termed Multi-rate Instantaneous Channel connected Data Flow (MRICDF) actor network model1. Sequential embedded software from MRICDF specifications can be synthesized using epoch analysis, a technique proposed to form a unique order of events without a reference time line. We show how to decide on the implementability of MRICDF specification and how additional epoch information can help in synthesizing deterministic sequential software. The semantics of an MRICDF is akin to that of SIGNAL, but is visual and easier to specify. Also, our prime implicate based epoch analysis technique avoids the complex clock-tree based analysis required in SIGNAL. We experimented with the usability of MRICDF formalism by creating EmCodeSyn, our visual specification and synthesis tool. Our attempt is to make polychronous specification based software synthesis more accessible to engineers, by proposing this alternative model with different semantic exposition and simpler analysis techniques.