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14.4 Functional Coverage Setup

Functional coverage has to be planned thoroughly. This section discusses the overall methodology for setting up coverage.

14.4.1 Coverage Process

One beings the coverage process by deriving information from the specification regarding items that need to be covered. Based on that information, a coverage model is created. The coverage model is run in conjunction with the test base and it provides coverage reports. These reports are analyzed to do one of the following:

Figure 14-10 shows a typical coverage process.

Figure 14-10. Coverage Process

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14.4.2 Coverage Plan

A coverage plan is a specification of a coverage model. A coverage plan contains information to be collected about attributes of the DUT, interactions between different attributes of the DUT, and a sequence of occurrences. A coverage plan also contains information about when these items should be collected. Figure 14-11 shows the example of a typical coverage plan.

Figure 14-11. Coverage Plan

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14.4.3 Coverage-Driven Verification Environment

Once the coverage process and the coverage plan are set up, the coverage-driven verification environment needs to be planned carefully. A good coverage environment includes automatic stimulus generation, self-checking, and a coverage monitor as an integral part of the environment. Optional manual guidance can be provided to direct the environment towards certain interesting areas. Figure 14-12 shows the setup of a typical coverage-driven verification environment.

Figure 14-12. Coverage-Driven Verification Environment

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