Functional testability measures based on information flow

To measure testability of circuits precisely is one of the important problems in digital system testing. This paper presents a method based on information flow to measure the testability of circuits. Digital circuits can be described by an information processing system. The testability measure is defined in terms of information flow across the digital circuit. Its value can be obtained by means of logic simulation software. For those circuits that contain many modules, the testability measure can be obtained by means of special operations among them. A corresponding example is demonstrated. Another example for testability measure is calculated and its results are compared with those previously obtained. The features of the method presented in this paper are described