Improving IJTAG Test Efficiency and Security

The IEEE Std. 1687 (IJTAG) provides a more efficient and flexible mechanism to access embedded instruments in complex system-on-chips (SoC). Embedded instruments are mainly used for testing, debugging, diagnosing, and post-silicon validation. In this paper, we propose a comprehensive protection method against data flow attacks in IJTAG networks. The network structure is arranged according to the access times of each instrument in to optimize the test efficiency and prevent third-party intellectual property attacks. Furthermore, we provide a method to group instruments to reduce hardware overhead and maintain the security. Experimental results show that the proposed methods achieve minimal overall access time (OAT) and segment insertion bit programming overhead.