IS-FPGA : a new symmetric FPGA architecture with implicit scan

Proposes a new and original FPGA architecture with testability facilities. It is first demonstrated that classical FPGA architectures do not allow one to efficiently implement sequential circuits with a scan chain. It is consequently proposed to modify the architecture of classical FPGAs in order to create an implicit-scan chain into the FPGA itself called implicit scan FPGA (IS-FPGA). Using this new FPGA architecture, any sequential circuit implemented into the FPGA is ´implicitly scanned´. An original and optimal implementation of the proposed architecture is given with minimum area overhead and absolutely no delay impact. Additionally the technique is transparent for the user as well as for the FPGA mapping tools. Finally, it is demonstrated that the implicit-scan concept allows ´over-scan´ of sequential circuits resulting in highly testable circuits