Test and diagnosis of faulty logic blocks in FPGAs

Since field programmable gate arrays (FPGAs) are reprogrammable, faults in them can be easily tolerated once fault sites are located. We present a method for the testing and diagnosis of faults in FPGAs. The proposed method imposes no hardware overhead, and requires minimal support from external test equipment. Test time depends only on the number of faults, and is independent of the chip size. With the help of this technique, chips with faults can still be used. As a result, the chip yield can be improved and chip cost is reduced. Experimental results are given to show the feasibility of this method.