Sequential Logic Synthesis

Book excerpt: Computer-aided design (CAD) of very large scale integrated (VLSI) circuits is concerned with the development of computer programs for the automated design and manufacture of ICs. Automated VLSI design is referred to as VLSI synthesis. Synthesis of VLSI circuits involves transforming a specification of circuit behavior into a mask-level layout which can be fabricated using VLSI manufacturing processes. Optimization strategies are vital in VLSI synthesis in order to meet desired specifications. However, the optimization problems encountered in VLSI synthesis are typically nondeterministic polynomial-time (NP)-complete or NP-hard. Therefore, solutions to the optimization problems incorporate heuristic strategies, the development of which requires a thorough understanding of the problem at hand. Thus, optimization-based VLSI synthesis has evolved into a rich and exciting area of research. Automata theory forms a cornerstone of digital VLSI system design. Sequential Logic Synthesis deals exclusively with finite automata theory and practice. The extensive use of finite state automata, finite state machines (FSMs) or simple sequential logic