Click Elements: An Implementation Style for Data-Driven Compilation

This paper presents a new design template and design flow for the implementation of data-driven asynchronous circuits. It relies on the use of edge-triggered flip-flops as the only storage elements, not only for the datapaths, but also for the control circuits; latches and C-elements that are common in many asynchronous circuit design styles are not required. The design template uses a two-phase handshake protocol for inter-component communication. In a pipeline structure, these circuits operate near the speed of Mousetrap circuits, but the required design-flow is simpler. The implementation style -which we refer to as Click elements - has been chosen to resemble synchronous circuits as much as possible. This allows for the use of conventional optimization and timing tools in the design flow and for a cheaper design-for-test implementation. The click templates are well suited for a data-flow driven compilation flow, which avoids much of the control overhead of traditional syntax-directed compilation. The two-phase circuits show a significant improvement in performance and energy efficiency compared to four-phase single-rail circuits.