JTAG DFT tool outlined at European
Board Test Workshop
Until recently, the quality of the JTAG DFT in a board design depended totally on the expertise of the board’s designer. But quite often, experts in board-level design are not necessarily expert in boundary-scan DFT. And, like other test methods, when JTAG is not designed into a project properly, test strategies can run amuck, costs may skyrocket and product quality suffer.
At the recent European Board Test Workshop, which was held last month in Chilworth, Southampton, UK, ASSET made a presentation on how its DFT Analyzer™, a rules-based JTAG DFT tool, could make every board-level designer an expert on designing in JTAG. The objective of DFT Analyzer is to ensure sound JTAG design practices have been followed, validate that a schematic reflects the proper implementation of good boundary-scan DFT and provide information on a design’s JTAG test coverage. If DFT Analyzer found that a design had extensive boundary-scan test coverage, for example, the design’s test strategy could be shifted, possibly de-emphasizing ICT test in favor of boundary scan test and saving significantly on the cost of ICT test fixtures.
The first phase of the tool’s deployment occurs during schematic capture when changes can be made without incurring significant costs. Next, DFT Analyzer extracts testability information from the design’s CAD files. This data is analyzed to determine whether sound JTAG DFT practices have been followed in the actual design. During this phase, for example, DFT Analyzer might inform the designer that the boundary scan path is broken.
In its last step DFT Analyzer reports on how much JTAG test coverage the design currently has and how changes could be made to increase the boundary scan test coverage. This phase of the analysis also provides a head start on developing production JTAG tests because in order to accurately gauge test coverage, the JTAG test generation process is run to detect any problems before actual test patterns are generated.
ASSET’s presentation at the board test workshop offered insights into the development of DFT Analyzer. Information gathered from the extensive beta testing of the tool was shared throughout the presentation. As the first DFT automation tool for JTAG, DFT Analyzer has been honored by Test and Measurement World magazine with a Best in Test honorable mention award for 2005.
For more information about DFT Analyzer, click here.
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