A bypass scheme for core-based system fault testing

We present a global design for test methodology for testing a core-based system in its entirety. This is achieved by introducing a "bypass" mode for each core by which the data can be transferred from a core input port to the output port without interfering with the core circuitry itself. The interconnections are thoroughly tested since they are used to propagate test data (patterns or signatures) in the system. The system is modeled as a directed weighted graph in which the core accessibility is solved as a shortest path problem.