UPF provides a consistent format to specify power design information that may not be easily specifiable in a design description. In certain situations it is undesirable to specify power semantics directly in the HDL, as doing so might tie down the implementation to certain power constraints. UPF provides a way to specify the power intent for different states and contexts, external to the design, to be used for implementation, modeling, simulation and verification. The semantics of UPF are consistent across implementation and verification, guaranteeing that what is being verified is indeed what was implemented.
UPF assumes a logical hierarchy that is a more abstract model of the design hierarchy. The logical hierarchy can be viewed as a conceptual structure for locating power management objects such as power domains and power states. Each object is defined in a specific scope of logical hierarchy. This logical hierarchy can be effectively used in a top-down UPF methodology, where the more abstract states are higher up in the hierarchy (global states), and the lower hierarchical objects are more refined versions of their ancestors. (more…)