SCOAP-based Directed Random Test Generation for Combinational Circuits

Abstract

In this paper, a heuristic method based on a pre-calculated prediction of tests is presented. This method is for combinational test generation and applies to the combinational parts of sequential circuits equally wells. The proposed method is Directed Random Test Generation that is based on SCOAP observability and controllability parameters. RTG methods are usually evaluated based on fault coverage that grows exponentially with the number of test vectors. Instead of pure random testing with a massive number of test vectors, fewer test vectors are selected by Directed Random Test Generation, and more faults are detected in the early stages of test generation. As a result, fewer faults remain for the deterministic test stage, which is helpful where online testing is considered. A comparison between random testing and directed random testing is performed on combinational benchmarks, using MATLAB and ModelSim simulation environments. The focus is on the stuck-at fault models in random logic circuits. The simulation results show our method has a sharper increase in fault coverage when compared with pure random test generation.