On the testability of IEEE 1687 networks

Due to the increasing usage of embedded instruments in many electronic devices, new solutions to effectively access these instruments appeared, including the new IEEE 1687 standard. The approach supported by IEEE 1687 allows a flexible access to embedded instruments through the Boundary Scan interface. The IEEE 1687 network includes a set of reconfigurable scan chains. This paper addresses the issue of testing the circuitry implementing them, checking whether any permanent hardware fault exists, affecting either the registers associated to the instruments made accessible by the network, or the configuration structures it embeds (e.g., the multiplexers and the associated flip-flops). The paper proposes an approach, in which the IEEE 1687 network undergoes a sequence of test sessions, each composed of a configuration phase and a test phase. By properly selecting the network configurations to be used, we can guarantee that the method can test any permanent fault possibly affecting the network. We also provide some experimental results gathered on a set of benchmark networks, allowing to practically evaluate the viability of the approach.