On improving FPGA routability applying multi-level switch boxes

In this paper, we propose a new FPGA switch box design style - the extended switch boxes. An extended switch box is multi-level in nature. It consists of a kernel and extension(s) connected to the kernel, while many conventional switch boxes only consist of the kernel part and are referred to as single-level switch boxes. We show that with a much reduced total number of manufactured switches in the chip, this new design has a guaranteed complete mappability from any global routing to a feasible detailed routing of the entire FPGA chip. The interesting results seem to open a new avenue for designing FPGA routing structures.