Cascade signature and syndrome compression

Abstract

A linear feedback shift register (LFSR) is commonly used in built-in self-test (BIST) and board-level testing schemes to compress the output response from the circuit under-test. The problem of aliasing, where errors go undetected, may occur with the LFSR-based compression. This paper describes a new method that reduces the probability of aliasing significantly. The method utilizes both LFSR-based signature analyser and syndrome counter techniques. Error detection capabilities and applications of the new method are also presented.