System-level testability of hardware/software systems

As modern digital hardware/software systems become more complex, the testing of these systems throughout their entire system life cycle, including design verification, production testing, and field testing, becomes a severe problem. In this paper a structured approach is presented to solve the problems of system-level testability. A strategy towards design for system-level testability is introduced, which consists of partitioning the system specification into testable parts, and inserting implementation-independent test functionality in the specification. Incorporating these test requirements in the hardware/software implementation will considerably improve system-level testability. The design and implementation of a traffic-lights control system is presented as an example to illustrate the benefits of this approach.