Hierarchical built-in test equipment of circuit system based on boundary scan

A hierarchical built-in test equipment of circuit system based on boundary scan, which consists of subsystem-level BITE, board-level BITE and component-level BITE, is presented. Structure and working principle of each level BITE is introduced in detail, after giving the hierarchical structure. Experiment is also carried out to verify the design. The system could combine the strong information obtaining ability in the inferior level BITE and the powerful information processing ability in superior level BITE to enhance the overall test capability of complex circuit system. It can be used for fault diagnosis and isolation of complex hierarchical circuit system in satellite and other spacecraft.