Symbolic hazard-free minimization and encoding of asynchronous finite state machines

• Published in: Proceedings of IEEE International Conference on Computer Aided Design (ICCAD) pp. 604 - 611
• Main Authors: Fuhrer, R.M., Lin, B., Nowick, S.M.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 1995
• Subjects: Automata; Computer science; Design optimization; Encoding; Hazards; Logic design; Microwave integrated circuits; Minimization; Multivalued logic; Synchronous machines
• ISBN: 0818682000; 0818672137; 9780818672132; 9780818682001
• ISSN: 1063-6757; 1092-3152; 1558-2434
• DOI: 10.1109/ICCAD.1995.480191

This paper presents an automated method for the synthesis of multiple-input-change (MIC) asynchronous state machines. Asynchronous state machine design is subtle since, unlike synchronous synthesis, logic must be implemented without hazards, and state codes must be chosen carefully to avoid critical races. We formulate and solve an optimal hazard-free and critical race-free encoding problem for a class of MIC asynchronous state machines called burst-mode. Analogous to a paradigm successfully used for the optimal encoding of synchronous machines, the problem is formulated as an input encoding problem. Implementations are targeted to sum-of-product realizations. We believe this is the first general method for the optimal encoding of hazard-free MIC asynchronous state machines under a generalized fundamental mode of operation. Results indicate that improved solutions are produced, ranging up to 17% improvement.