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Unformatted text preview: 46 VLSI Test Principles and Architectures Many methods have been developed to calculate the probabilitybased testability measures. A simple method is given below, whose basic procedure is similar to the one used for calculating combinational testability measures in SCOAP except that different calculation rules are used. The rules for probabilitybased controllability and observability calculation are summarized in Tables 2.3 and 2.4, respectively. In Table 2.3, p is the initial 0controllability chosen for a primary input, where < p < 1. Compared to SCOAP testability measures, where nonnegative integers are used, probabilitybased testability measures range between 0 and 1. The smaller a probabilitybased testability measure of a signal, the more difficult it is to control or observe the signal. Figure 2.3 illustrates the difference between SCOAP testability TABLE 2.3 ProbabilityBased Controllability Calculation Rules 0Controllability (Primary Input, Output, Branch) 1Controllability (Primary Input,...
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This note was uploaded on 05/16/2011 for the course ENGINEERIN mp108 taught by Professor Elbarki during the Spring '08 term at Alexandria University.
 Spring '08
 elbarki

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