Impact of hard macro size on FPGA clock rate and place/route time

Abstract

Hard macros are completely placed/routed elements that are treated as primitives and that are relatively placed as a single element. A system composed of such macros consists of many fewer effective primitives and nets and as such can be placed and routed much more quickly. Prior work in this research area dealt with small, general-purpose macros such as 16-bit registers, adders, etc., and demonstrated that place/route time could be reduced by an order of magnitude with a corresponding 3-4X reduction in clock rate. In this work, much larger hard macros are developed such as mixers, softcore processors, FFTs, etc., and the use of these larger macros is shown to further reduce place/route time by an additional 2.5-4X, for a total of a 30-40X reduction in compile time. Clock rate is also improved, relative to earlier work, by an additional 60-70%.