Tree restructuring approach to mapping problem in cellular-architecture FPGAs

A new technique for mapping combinational circuits to fine-grain cellular-architecture FPGAs is presented. The proposed tree restructuring algorithm preserves local connectivity and allows direct mapping of the tree to the cellular array, thus eliminating the traditional routing phase. The developed bus assignment algorithm efficiently utilizes medium and long distance routing resources (buses). The method is general and can be used for any fine-grain cellular-architecture type FPGA. To demonstrate our techniques, the ATMEL 6000 series FPGA was used as a target architecture. The results are very encouraging.