The interpretation and application of Rent's rule
IEEE Transactions on Very Large Scale Integration (VLSI) Systems - Special issue on system-level interconnect prediction
Unifying mesh- and tree-based programmable interconnect
IEEE Transactions on Very Large Scale Integration (VLSI) Systems
A new Multilevel Hierarchical MFPGA and its suitable configuration tools
ISVLSI '06 Proceedings of the IEEE Computer Society Annual Symposium on Emerging VLSI Technologies and Architectures
A multilevel hierarchical interconnection structure for FPGA
Proceedings of the 2006 ACM/SIGDA 14th international symposium on Field programmable gate arrays
On a Pin Versus Block Relationship For Partitions of Logic Graphs
IEEE Transactions on Computers
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This article does a purely mathematical analysis based on generic models, and the idea is to investigate the possibility of using tiling patterns other than Manhattan grid in FPGAs. The goal of our research is to evolve FPGA architectures with advances in technology, and specifically better utilization of available interconnect layers. We propose a method to evaluate tiling patterns based on the first principles ( i.e Rent's Rule, Donath's result, equivalence of wire flux and wire length). We show that, use of tiling patterns formed with higher order polygons can improve the speed and area performances of an FPGA. This gain is highly dependent on depopulation schemes and other parameters. However for generic tiling patterns with crossbar switchboxes there is a 22% gain in area for the hexagonal tiling pattern, and a 30% gain in area for the octagonal tiling pattern. Moreover the average interconnect length is around 15% lesser for hexagonal and 31% lesser for the octagonal tiling compared to square tiling. We can expect a proportional increase in speed. We also present a comparative plot of total interconnect lengths for these tiling patterns and the hierarchical gate arrays The physical realizability of these tiling patterns in CMOS are to be investigated. We present a layout scheme for both hexagonal and octagonal FPGAs. To our knowledge standard processes support 45° metal lines, whereas 60° lines can be etched using non-standard processes. We must keep in mind, that in practice one must use some sort of depopulation and staggering scheme, and these results provide only an idea of gains that can be achieved. The actual interconnect structure is of course dependent on several factors (i.e available interconnect layers, difficulty of fabrication, required speed/area, evolution of CMOS technology etc). Our future research direction will be to choose an efficient interconnect strategy based on this and previous researches, as well as experimental results