Maximum length pseudo-random test pattern generator via feedback network modification

Abstract From the Canadian patent

A system and method for generating 2n test patterns is disclosed. The system utilizes a linear feedback shift register (LFSR) to generate a sequence of 2n-1 test patterns. In addition the, system includes apparatus external to the shift register which generates a 2nth test pattern. A switching circuit is employed to insert the 2nth test pattern into the sequence of test patterns. Therefore a 2n test pattern sequence is generated. The test pattern sequence produced is pseudo-random in nature. The system further includes an output for providing a test pattern; such output could be used for the testing of a VLSI sub-system such as ROM. A method utilizing the techniques embodied in the system …