High-level test generation for asynchronous circuits from signal transition graph

In this paper, we have proposed an efficient high-level test generation method for asynchronous circuits. The test generation is based on specification level, especially on Signal Transition Graph (STG), which is a kind of specification method for asynchronous circuits. We define a high-level fault model, called a single State Transition Fault (STF) model on STC. Test patterns for STFs are generated based on Stable State Graph (SSG), which can be derived from STG directly. The state space explored in test generation is greatly reduced and hence the test generation cost is small in terms of execution time. To enhance the fault coverage at gate-level, we have also proposed an extended STF (ESTF) model with additional gate-level information. Experimental results show that the generated test for STFs achieves high fault coverage with low cost for single stuck at faults of its corresponding synthesized gate-level circuit. The generated test for ESTFs attains higher fault coverage with same benchmark in cost of longer execution time. Further, we have also proposed a 3-phase test generation based on the above proposed methods. An effective test generation is implemented by 3-phase: 1) test generation for STFs, 2) test generation for ESTFs, and 3) test generation using an asynchronous product machine traversal method. Experimental results also show that the proposed 3-phase test generation achieves higher fault coverage in cost of longer execution time.