Systematic functional coverage metric synthesis from hierarchical temporal event relation graph

Functional coverage is a technique for checking the completeness of test vectors in HDL simulation. Temporal events are used to monitor the sequence of events in the specification. In this paper, automatic generation of temporal events for functional coverage is proposed. The HiTER is the graph where nodes represent basic temporal properties or subgraph and edges represent time-shift value between two nodes. Hierarchical temporal events are generated by traversing HiTER such that invalid, or irrelevant properties are eliminated. Concurrent edge groups make it possible to generate more comprehensive temporal properties and hierarchical structure makes it easy to describe large design by combining multiple subgraphs. Automatically generated temporal events describe almost all the possible temporal properties of the design under verification.