Automatic Synthesis of Extended Burst-Mode Circuits: Part I (Specification and Hazard-Free Implementations)

We introduce a new design style called extended burst-mode. The extended burst-mode design style covers a wide spectrum of sequential circuits ranging from delay-insensitive to synchronous. We can synthesize multiple-input change asynchronous finite state machines, and many circuits that fall in the gray area (hard to classify as synchronous or asynchronous) which are difficult or impossible to synthesize automatically using existing methods. Our implementation of extended burst-mode machines uses standard CMOS logic, generates low-latency outputs, and guarantees freedom from hazards at the gate level. In Part I, we formally define the extended burst-mode specification, provide an overview of the synthesis method, and describe the hazard-free synthesis requirements for two different next-state logic synthesis methods: two-level sums-of-products implementation and generalized C-elements implementation. We also present an extension to existing theories for hazard-free combinational synthesis to handle non-monotonic input changes. Keywords— Asynchronous controller, Extended burst-mode, Hazardfree synthesis, Generalized C-element