DIALOG: An Expert Debugging System for MOSVLSI Design

An expert system (DIALOG) is described to check correctness of logic levels and timing composition rules in n- or CMOS VLSI logic. Knowledge is described in an engineer oriented language (LEXTOC) allowing for unification (cfr PROLOG), object creation, property assignment, association of relations, rule formulation, logic or arithmetic evaluation as well as conversational constructs. The system is illustrated by checking racefree dynamic CMOS design composition rules. Up to 250 transistors can be handled in the LISP interpretative way on the VAX 11/780. An efficient automatic translation of LEXTOC into Pascal shows the feasibility for batch oriented debugging of up to 50,000 transistors in a workstation environment, while keeping knowledge programming efficiency of LEXTOC.