Functional Broadside Tests With Incompletely Specified Scan-In States

Functional broadside tests address overtesting of delay faults by using reachable states as scan-in states. Since reachable states are, in general, fully specified, functional broadside tests are not amenable to the commonly used test data compression methods. This paper defines multicycle functional broadside tests whose scan-in states are incompletely specified. The first clock cycles of a test bring the circuit from the scan-in state into a reachable state without activating delay faults. The last two clock cycles detect delay faults by applying a two-cycle functional broadside test. This paper also describes a test generation procedure for tests of this type. The procedure uses a condition, which is based on the initial state of the circuit for functional operation, to simplify the generation of the tests.