Coordinating routing resources for hex pips test in island-style FPGAs (abstract only)

The significance of FPGA test and the challenge of its increasing cost can never be ignored. In island-style FPGA architectures, hex lines are the principal interconnect resources. Testing hex lines and hex Programmable Interconnect Points (PIPs) have remained as the major technical difficulty in FPGAs test due to complex interconnect rules. Particularly, test in oblique direction of hex PIPs has rarely been addressed in previous studies. Towards this challenge, this paper for the first time proposes a coordinate system and formulates the interconnect rules of hex lines as mathematical equations. For hex PIPs in horizontal and vertical direction, an efficient circle test structure is formed by coordinate equations. For hex PIPs in oblique direction, the coordinate method is used to generate the partial-cascade pattern. The corresponding test vector is also generated, which ensures the ergodicity of hex PIPs in oblique direction. In addition to hex PIPs, hex lines are also covered without extra effort. Compared to previous researches, the configuration number for hex lines is decreased significantly. We evaluate this method on Xilinx XC2V1000, and experimental results show that our proposed method achieves 100% fault coverage for hex PIPs and can be generally applied to all mainstream island-style FPGAs with a similar interconnect structure currently.