Application-Dependent Delay Testing of FPGAs

Testing of field-programmable gate array (FPGA) resources used for mapping a particular design (application-dependent testing) is a key factor in FPGA defect tolerance for yield enhancement and cost reduction as well as online testing in adaptive reliable computing. The majority of the FPGA real estate is dedicated to the interconnect network, and defects in the interconnects manifest themselves as delay faults. In this paper, a very thorough application-dependent interconnect delay testing technique is presented. Achieving a high coverage on path delay fault has been traditionally intractable for application-specific integrated circuits. However, by leveraging the reconfigurability of FPGAs, the presented technique is able to achieve 100% robust path delay coverage on all the paths in the design. This automatically results in 100% transition fault coverage. The required number of test configurations is two or four, depending on the structure of the design. Algorithms with linear time complexity are presented for automatic test configuration and test vector generation