Integrated test of interacting controllers and datapaths

In systems consisting of interacting datapaths and controllers and utilizin g built-in self test (BIST), the datapaths and controllers are traditionall y tested separately by isolating each component from the environment of the system during test. This work facilitates the testing of datapath/controll er pairs in an integrated fashion. The key to the approach is the addition of logic to the system that interacts with the existing controller to push the effects of controller faults into the data flow, so that they can be ob served at the datapath registers rather than directly at the controller out puts. The result is to reduce the BIST overhead over what is needed if the datapath and controller are tested independently, and to allow a more compl ete test of the interface between datapath and controller, including the fa ults that do not manifest themselves in isolation. Fault coverage and overh ead results are given for four example circuits.