A new framework for designing: built-in test multichip modules with pipelined test strategy

A novel test strategy, the Loop Testing Architecture (LTA), is introduced to reduce aliasing probability and testing time for multichip modules. This is accomplished by connecting cascadable built-in testers (CBITs) in neighboring pipelined stages to increase the length of the test suites. Fundamental properties of the LTA supporting randomness in the generated test patterns (state coverage) and the asymptotic aliasing probability are presented. Results on two small-scale multiprocessor configurations show that the aliasing probability in analyzing signatures is comparable to that of an MLFSR but with fairly low area overhead; compared with the circular self-test path technique, less testing time is required by LTA. Further evaluation of the potential capabilities provided by the LTA compared with boundary scan and other pipelined test scheduling approaches confirmed the usefulness of LTA as a framework for designing effective testable systems.<>