Built-In Generation of Functional Broadside Tests Using a Fixed Hardware Structure

Functional broadside tests are two-pattern scan-based tests that avoid overtesting by ensuring that a circuit traverses only reachable states during the functional clock cycles of a test. In addition, the power dissipation during the fast functional clock cycles of functional broadside tests does not exceed that possible during functional operation. On-chip test generation has the added advantage that it reduces test data volume and facilitates at-speed test application. This paper shows that on-chip generation of functional broadside tests can be done using a simple and fixed hardware structure, with a small number of parameters that need to be tailored to a given circuit, and can achieve high transition fault coverage for testable circuits. With the proposed on-chip test generation method, the circuit is used for generating reachable states during test application. This alleviates the need to compute reachable states offline.