Power-aware test scheduling in network-on-chip using variable-rate on-chip clocking

Network-on-chip is the new paradigm in core-based system design. Reuse of the on-chip communication network for NoC test is critical to reduce test cost. However, efficient reuse of the communication network for test of legacy cores is challenging. A mismatch between the NoC channel width and the core test wrapper width can adversely affect test efficiency. In addition, stringent power constraints on today´s high-density systems exacerbate the test scheduling problem. In this paper, we propose a method for efficiently utilizing the on-chip network for power-aware test scheduling in NoCs. We make use of on-chip clocking to speed up test data transfer by selectively using faster clocks to test certain cores; other cores receive slower clocks to limit test power consumption. A method is presented to determine the clock rate distribution among cores. Experimental results for the ITC ´02 benchmarks show that the new method leads to substantial reduction in overall test application time, while satisfying power constraints.