P1149.4 Mixed-Signal Test Bus

The IEEE P1149.4 Mixed-Signal Test Bus Working Group has been busy developing a usable standard addressing analog testability issues for mixed-signal technologies. The Working Group's charter is to define, document, and promote the use of a standard mixed-signal test bus that can be used at the device and assembly levels to improve the controllability and observability of mixed-signal designs and to support mixed-signal built-in self-test structures in order to reduce test development time, testing costs, and improve test quality.This short article will update the reader with the current standard architecture proposal, explain how the architecture can be used in a test scenario, and challenge the reader to respond to the Working Group with solutions or observations concerning some current topics of debate within the group. This standard is still in the stages of finalization, and the ideas and constructs presented here are proposals generally accepted by the Working Group, but may still change for technical or other reasons.