Pseudorandom number generator, semiconductor integrated circuit, pseudorandom number generator control apparatus, pseudorandom number generator control method, and computer product

摘要

In a linear feedback shift register (LFSR), a four-bit shift register mainly using F/Fs is formed and an XOR circuit that feeds back an exclusive OR of a first bit and a last bit to the first bit is also provided, thereby outputting a test pattern having a maximum cycle of 15. A phase change circuit that can perform arbitrary phase change of a test pattern based on input of a control signal having a maximum clock number 4 and an average clock number log₂4 is also formed in the LFSR. As a result, a smaller clock count is required for the LFSR to output a test pattern that matches a test pattern automatically generated by an ATPG.