PICSIL: integrating graphic system design and automatic synthesis

Abstract

We present an approach to the design of complex logic ICs, developed from four premises. First, the responsibilities of a chip's major components, and the communication between them, should be separated from the detailed implementation of their functionality. Design of this abstract architecture should precede definition of the detailed functionality. Secondly, graphic vocabularies are most natural for describing abstract architectures, by contrast with the conventional textual notations for describing functionality. Thirdly, such information as can be expressed naturally and completely in the idiom of the abstract architecture should be automatically translated into more complex, lower-level vocabulary. Fourthly, the notations can be integrated into a single, consistent design-capture and synthesis system. PICSIL is a preliminary implementation of a design environment using this approach. It combines an editor and a synthesis driver, allowing a design's abstract architecture to be created using a graphical notation based on Data Flow Diagrams and state machines, and its functionality to be designed using a more conventional textual hardware description language. On request, it also translates a design into appropriate input for synthesis software, and controls the operation of that software, producing CIF files suitable for fabrication. Thus computer systems become appropriate for ab initio design production rather than post facto design capture.