FPGA switch block layout and evaluation

ABSTRACT

This paper presents abstract layout techniques for a variety of FPGA switch block architectures. We evaluate the relative density of subset, universal, and Wilton switch block architectures. For subset switch blocks of small size, we find the optimal implementations using a simple metric. We also develop a tractable heuristic that returns the optimal results for small switch blocks, and good results for large switch blocks. For switch blocks with general connectivity, we develop a representation and a layout evaluation technique. We use these techniques to compare a variety of small switch blocks. We find that the traditional Xilinx-style, subset switch block is superior to the other proposed architectures. Finally, we have hand-designed some small switch blocks to confirm our results.

REFERENCES

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INDEX TERMS

Keywords:
FPGA interconnect, VLSI layout