The post office experience: designing a large asynchronous chip

The Post Office is an asynchronous, 300,000 transistor, full-custom CMOS chip designed as the communication component for the Mayfly scalable parallel processor. Performance requirements led to the development of a design style which permits the design of sequential circuits operating under a restricted form of multiple input change sign alling called burst-mode. The Post Office complexity forced us to develop a set of design fools capable of correctly synthesizing transistor circuits front state machine and equation specifications, and capable of verifying the correctness of the resultant circuity using implementation specific timing assumptions. The paper provides a case study of this design experience.