Alternative run-length coding through scan chain reconfiguration for joint minimization of test data volume and power consumption in scan test

Test data volume and scan power are two major concerns in SoC test. In this paper we present an alternative run-length coding method through scan chain reconfiguration to reduce both test data volume and scan-in power consumption. The proposed method analyzes the compatibility of the internal scan cells for a given test set and then divides the scan cells into compatible classes. To extract the compatible scan cells we apply a heuristic algorithm by solving the graph coloring problem; and then a simple greedy algorithm is used to configure the scan chain for the minimization of scan power. Experimental results for the larger ISCAS´89 benchmarks show that the proposed approach leads to highly reduced test data volume with significant power savings during scan test.