Approaching board test nonintrusively.(TEST SOFTWARE)

It's inevitable. Basic electronic technology evolves. Chips and circuit boards are designed and made differently today than they were 10 years or even five years ago. It stands to reason that the technologies that manufacturers have deployed to test chips and circuit boards would evolve right along with the chips and boards.

In a quiet way, test methods have evolved. But now the test industry is fast approaching a tipping point where the older, intrusive, hardware-based test techniques must be complemented, supplemented, or outright replaced by newer, software-driven, nonintrusive test technologies. What's driving this trend is what has always driven the test industry: test coverage. Without it, test engineers look elsewhere, and that's what they're doing today.

New nonintrusive board test (NBT) techniques are making significant inroads for two reasons:

* Test coverage is eroding because today's evolved technologies can't be tested with the old methods.

* The economics of today's electronics industry demands more cost-effective test methods such as NBT.

Where's the Coverage Going?

Nonintrusive test technologies like boundary scan (JTAG), processor-controlled test (PCT), and certain types of BIST such as Intel's Interconnect Built-in Self-Test (IBIST) have a big advantage over the older, intrusive test technologies, including in-circuit testers (ICT), manufacturing defects analyzers (MDA), flying-probe testers, oscilloscopes, and logic analyzers. The software-driven nonintrusive techniques do not require physical contact with a chip or board the way that probe-based or bed-of-nail intrusive technologies do. …

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