BS 1149.1 extensions for an online interconnect fault detection and recovery

Loss of signal integrity in today's deep sub-micron designs puts communication links at a higher risk of permanent or more frequent intermittent faults. This results in performance and reliability reduction. This paper presents an online interconnect BIST method that applies to a hybrid serial/parallel communication scheme. The proposed BIST method is implemented by a simple extension to the boundary scan standard, which facilitates online testing methodology with negligible hardware overhead. The online hardware works in the idle state of the Boundary Scan TAP controller. The proposed method includes fault detection and diagnosis phases. Moreover, for error handling, it uses the same test hardware added to the communication interface. It effectively reuses the existing boundary scan structure to act as a signature generator, an error detector and locater for testing interconnects, and an error handling mechanism. Our method can detect about 90% of the interconnect faults after six block transfers.