Efficient algorithms for the design of asynchronous control circuits

Abstract

Asynchronous (or “clock-less”) digital circuit design has received much attention over the past few years, including its introduction into consumer products. One major bottleneck to the further advancement of clock-less design is the lack of optimizing CAD (computer-aided design) algorithms and tools. In synchronous design, CAD packages have been crucial to the advancement of the microelectronics industry. In fact, automated methods seem to be even more crucial for asynchronous design, which is widely considered as being much more error-prone. This thesis proposes several new efficient CAD techniques for the design of asynchronous control circuits. The contributions include: (i) two new and very efficient algorithms for hazard-free two-level logic minimization, including a heuristic algorithm, ESPRESSO-HF, and an exact algorithm based on implicit data structures, IMPYMIN; and ( ii) a new synthesis and optimization method for large-scale asynchronous systems, which starts from a Control-Dataflow Graph (CDFG), and produces highly-optimized distributed control. As a case study, this latter method is applied to a differential equation solver; the resulting synthesized circuit is comparable in quality to a highly-optimized manual design.