5.30.1.1.1 Power-Driven

Select this option to run Power-Driven Layout. The primary goal of power-driven layout is to reduce dynamic power while still maintaining timing constraints.

To get the most out of Power-Driven Layout, it is recommended to:

  1. Enter maximum delay, minimum delay, setup, and hold constraints in SmartTime's constraint editor or in SDC.
    1. Set false paths on any paths that have a constraint, but do not need one (this will help layout meet the constraints that are needed).
      1. Perform Layout with Timing-Driven, Run Place, and Run Route options checked.
  3. Resolve worst case setup and maximum delay violations.
  4. Generate an SDF back-annotation file.
    1. Perform a post layout back-annotated simulation using this SDF file, and export a VCD (Value Change Dump) file that will capture real activities for each net.
  5. Import this VCD file in Designer using the Import Auxiliary option from the File menu.
    1. Perform Layout with Timing-Driven and Power-Driven checked. Run Place and Route.
    2. Verify that your timing constraints are still met with SmartTime.
  6. Analyze your power with SmartPower.

In case you do not have simulation vectors for your design, the following alternative flow is recommended:

  1. Enter maximum delay, minimum delay, setup, and hold constraints in SmartTime's constraint editor or in SDC.
    1. Set false paths on any paths that have a constraint, but do not need one (this will help layout to meet the constraints that are needed).
  2. Perform Layout with Timing-Driven, Run Place, and Run Route options checked.
  3. Resolve worst case setup and maximum delay violations.
  4. Verify that your timing constraints are still met with SmartTime.
    1. Open SmartPower and set clock frequencies and toggle rates for the different clocks. Clock frequencies can be imported from your timing constraints. Refer to Initialize Frequencies for more information.
      1. Perform Layout with Timing-Driven, and Power-Driven options checked. Run Place and Route.
  5. Verify that your timing constraints are still met with SmartTime.
    1. Analyze your power with SmartPower