The Test Engineer's Assistant: a design environment for testableand diagnosable systems

The Test Engineer's Assistant (TEA) is a set of computer-aided design (CAD) tools that helps the system design engineer meet testability requirements by construction. TEA addresses system design for testability at all levels of the design hierarchy, the lowest level being the board level. The design is represented as a graph where each node indicates a hardware component (or chip on a board) and each arc represents intercomponent connections. Attributes associated with the graph nodes and a set of rules and testing techniques that are incorporated in the tool databases are used to determine the design features that have to be incorporated into the design to meet test and diagnostic requirements. The tool operates on a design using a combination of algorithmic and heuristic techniques. The authors present the design methodology supported by TEA, discuss the techniques used by the TEA tools to obtain solutions for different design for testability requirements, and present an example of the use of TEA with a real system