Fast hierarchical test path construction for DFT-free controller-datapath circuits

We discuss a hierarchical test generation method for DFT-free controller-datapath pairs. A transparency based scheme is devised for the datapath, wherein locally generated vectors are translated into global design test. The controller is examined through influence tables, used to generate valid control state sequences for testing each module through hierarchical test paths. Fault coverage levels and vector counts thus attained match closely, those of traditional test generation methodologies, while sharply reducing the corresponding computational cost.