Why Do We Need Code and Functional Coverage

When you have a test that can generate 1 out of 1000 different types of stimulus at any given moment, it is not safe to assume that permutation #379, which you consider to be necessary to confirm some vital functionality of the chip design, was in fact generated. Assuming all 1000 permutations of stimulus are equally likely to be generated, permutation #379 would have a 0.1% chance of ever being generated. The diagram Random Testing Suffers From Lack of Observability depicts this circumstance: state space of a design (the big circle), random tests (the grey clouds), and particular locations in the state space of the design that are considered to be high-priority testing points (small greyed out dotted line circles). <a href="https://magreen.medium.com/why-do-we-need-code-and-functional-coverage-e9f607a677c2">Visit Now</a>