The application of knowledge based systems to the design of VLSI circuits will have the greatest impact in assisting the engineer with aspects of the design which are not amenable to automation using algorithmic techniques. Test pattern generation and design for testability fall into this category. A further advantage offered by knowledge based systems is that they can 'acquire' knowledge for future use and hence improve their capabilities and the 'quality' of the solutions provided. Although expert systems offer many potential benefits a major barrier to their use is the high develop ments costs. These start-up costs can be offset to some extent by using expert system shells or by using logic programming languages e.g. Prolog, so that prototype systems can be produced relatively quickly and the required knowledge bases built up incrementally. In retrospect start-up costs were considered to be an obstacle to the development of conven tional CAD programs. These are now widely used and development costs, although still considerable, are accepted primarily because these tools have been shown to provide tangible benefits to the designer. Consequent ly, if development costs of expert systems are to be accepted these tools must demonstrate that they can also provided tangible benefits to the designer.

Inspec keywords: CAD; VLSI; PROLOG; design for testability; expert systems

Other keywords: knowledge based expert systems; logic programming languages; VLSI circuit design; Prolog; design for testability; algorithmic techniques; retrospect start-up costs; test pattern generation; CAD programs

Subjects: Semiconductor integrated circuit design, layout, modelling and testing