EVE: a CAD tool for manual placement and pipelining assistance of FPGA circuits

ABSTRACT

As FPGAs push ever deeper into mainstream digital design, there is an increasing desire for high-performance circuits. This paper describes a manual editor, called EVE, which can assist a designer to perform manual packing, placement and pipelining of commercial FPGA circuits to achieve a meaningful increase in performance. This effort is inspired by Von Herzen's paper [15] [16], which proposed the notion of an "Event Horizon" - a high-speed circuit design approach in which complete knowledge of the timing effect of every synthesis change is used. It is very laborious to implement circuits using this approach; therefore we try to augment manual design tools in order to make this Event Horizon methodology easier to perform. This paper describes a first step in that direction, which focuses on placement, packing and pipelining. EVE provides an interactive environment that immediately reroutes and timing analyzes after each user circuit modification, giving an exact value for critical path delay. It can also suggest good placement positions and provide flip-flop insertion assist during pipelining. Compared to a state-of-the-art Synthesis and place and route flow, we used EVE to achieve an average of 12.7% higher operating frequency on a set of eight Xilinx Virtex-E circuits of 250 or fewer LUTs.

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INDEX TERMS

Keywords:
FPGA, event horizon, manual placement and pipelining, programmable logic