A Language for Describing Boundary-Scan Devices
The 1149.1 Boundary-Scan Standard was first approved early in 1990. The Standard was rich in features - mandatory and optional - but a major weakness was that there was no specification of how to describe the detail of a particular implementation within an 1149.1-compliant component. Essentially, an end-user (a board test programmer, for example) would need this detail for every 1149.1 component on the board before creating a test program. Although conceptually easy to provide, the lack of a formal language could easily have led to a "Tower of Babel" and become a major barrier to the early adopters of boundary scan. Ken Parker and Stig Oresjo's paper put a stake in the ground by defining a Boundary Scan Description Language (BSDL) based on the well-known design language VHDL. Their proposal was adopted, both by the end-user community and by the Standard's Working Group and was formally incorporated into the Standard in 1994 in the form of a free-standing appendix. In the latest version, 1149.1-2001, BSDL is both fully integrated and mandated and follow-on boundary scan Standards such as 1149.4, 1149.6 and 1532 all make use of this same language. Without doubt, the ITC 1990 BSDL paper prevented what could have been a chaotic introduction of the new Standard and, one can argue, removed a major barrier to early acceptance of the Standard.
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