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204 || AWSAR Awarded Popular Science Stories - 2019
by high bandwidth wireless interfaces (WIs). This, significantly, increases the speed of trace data transfer. While the traditional JTAG interface used for trace transfer can send data for around 800 Mbps, wireless interface in our proposed technique can export data at the speed of 16 Gbps. This provides around 20x times more improvement in trace transfer speed. In our method, the whole SoC can be divided into multiple sub-networks each having a single wireless interface (WI). After trace collection, the traces from each router can be transported to the nearest WI using wired path. All the WIs on the SoC can then transfer the traces to an external debug analyzer using wireless links as can be seen in Fig. 2.
The packet trace contains the packet number, current routing state of the packet and the timestamp. In the analyzer, the traces corresponding to a particular packet are stitched together with the help of the packet number value. The traces are sorted based on the corresponding timestamp. Further packet states are restored by using a state restoration algorithm. More the states are restored, more is the system observability. The packet states help in reconstructing the path taken by the packet. Then using a fault detection algorithm, faults are detected (if any), and localized with the help of the reconstructed path.