Naturally, vectors optimised in this way are likely to contain multiple and simultaneous level changes. Almost all component pins switch during the change between these checks and, in turn, increase the likelihood of ground-bounce. The combination of these two effects further induces ground-bounce problems. During a boundary-scan test, a board malfunction leads to an interconnection test abort. The diagnosis message indicates a scan path interruption, although the infrastructure test previously executed did not detect a failure.
Investigations reveal that a particular test vector reproduces the problem.
At this vector in the test sequence the boundary-scan test logic switches from the test state to the normal mode. This ground-bounce effect renders the overall test program meaningless. Since an interconnection test is an indispensable part of an entire boundary-scan test strategy, you have to consider how to overcome the problem. The first approach is time consuming and expensive. The second approach provides lower fault coverage because the system won't detect faults between the subdivisions.