A Network-Coding-Based Functional Test Method for Routers in 3-D Mesh NoCs

The 3-D Mesh Network-on-Chip (NoC) is widely used as the communication backbone of the 3-D multiprocessor system-on-chips (MPSoCs) and chiplet-based 3-D integrated systems, which enable the efficient computation paradigm in Internet of Things (IoT) scenarios. The functional test is a good choice for the 3-D Mesh NoCs to detect the defects introduced in manufacture process, because it reuses the at-speed on-chip network and consumes little hardware overhead. However, the test time of the functional test in 3-D Mesh NoCs grows dramatically with the NoC size. In order to reduce the test time on the premise of ensuring fault coverage, this work proposes a functional test method leveraging the exclusive OR (xor) network coding (NC) technique. In this work, thexor NC function is embedded in the routers by the extension modules with an additional area overhead less than 3%, and an efficient functional test process based on the embeddedxor NC function is proposed. The proposed functional test process covers all the straight and turning paths, and all the working modes of the routers are tested. The time complexity of the proposed method only increases linearly with the NoC size, which manifests that the proposed test method is applicable for the large-scale 3-D Mesh NoCs.