In this paper the user interface and program organization of the SYMPLE VLSI symbolic layout editor is examined. The user interface is driven by a small interpreter that is constructed from a LISP-like language at run time and has access to a consistent library of menus and graphical information-gathering functions. To improve maintainability, the editor has been constructed in a modular form with well-defined interfaces.

VLSI design requires design methodologies which are tailored to the implementation technology. Symbolic layout has been addressed in the past for MOS technology, while bipolar technology has largely been ignored. This paper describes a novel symbolic design technique which addresses both bipolar and MOS technologies. The technique allows the designer to symbolically layout nMOS, CMOS, and bipolar circuit structures. The symbol set is used for both MOS and bipolar devices in an integrated and consistent way. It is closely related to the mask layout information rather than circuit schematics. Thus, it allows the creation of any circuit structure based on bipolar, MOS, CMOS, BIMOS, and BICMOS technologies. Design examples are given.