Developments in testability standards

Following the publication of IEEE Standard 1149.1 (Feb. 1990), there has been widespread acceptance within the electronic circuit design community of this methodology as a means of producing testable digital circuits. The mixed-signal Standard, 1149.4, initially failed to find a sponsor and was put into abeyance; but a Working Group has now been formed under the Chairmanship of Professor Mani Soma of the University of Washington in Seattle. In November 1991, the work was endorsed by the Test Technology Technical Committee of the IEEE Computer Society, and the Working Group has since had two meetings (January and April 1992). This paper is intended to bring this activity to the attention of the Design and Test community in the UK, and to invite all interested parties to participate in the process of forming the new Standard. The process of testing an analogue or mixed-signal circuit can be broken down into a number of sub-problems, each of which will have its own requirements and limitations, and all of which have to be solved before a complete testability structure can be defined. A similar group of problems has previously been faced with digital circuits