Limited access testing: IEEE 1149.4-instrumentation and methods
J.E. McDermid · 2002
The IEEE 1149.4 standard is now poised for inclusion in a new generation of products. Successful application of this important new standard will depend on the availability of supporting methods and instrumentation. While the standard supplies a common architecture, the test engineer must now supply both method and instrumentation. This paper describes proven instrumentation concepts used to demonstrate IEEE 1149.4 measurements on the MEI test chip. Additionally, the paper discusses how current-stimulus and voltage-measurement techniques can be used to diagnose faulty components in medium sized networks of 75 to 150 components. IEEE 1149.4 tests can be automatically generated rather than hand crafted as in functional testing. Unlike digital resting, the technique does not use fault models. Correct operation is found by examining the deviation from nominal performance, greatly simplifying the test development task.