Test access mechanism for supporting a configurable built-in self-test circuit and method thereof

摘要

A configurable test access mechanism has a sliced input wrapper, output wrapper and scan configuration wrapper coupled to a circuit under test. The input wrapper efficiently adds a PRPG (pseudo-random pattern generator) function to a scan test structure without impacting speed and power requirements. The output wrapper efficiently adds a MISR (multiple input signature register) functionality for additional test purposes to implement a built-in self-test (BIST) apparatus. Use of existing scan structures to implement the PRPG and MISR functions provides significant savings of circuitry. Variability of test polynomials is easily user programmed.