Digital Circuit Testability Algorithms And C + + Program

Testability measure for a digital system is a quantitative indication which reflects the difficulty or ease degree while a circuit is tested. Testability for digital circuit is expressed with controllability and observability. Early in the design process of a circuit, Testability analysis of the designed circuit is given in order to evaluate its testability. To be easy for the testing of digital system, the design of the circuit with too bad testability must be modified to improve its testability. The paper introduces testability and testability measure calculation formula of each standard unit for digital circuit and concentrates on testability algorithm. Here, standard units include basic gate circuits, flip-flops and other basic combinational logic circuits. Based on the algorithm, the C++ program is developed. For a given digital circuit, by running the program, the testability value of any line in a circuit is obtained. In the final chapter of the paper, the testability value for a given digital and the testability value for its improved circuit are given. The result which corresponds to the fact is obtained, which shows the feasibility of the testability algorithm and the idea of C++ program design.