ISE Design Suite
Place & Route Properties
The following properties apply to the Place & Route and Implement Design processes for FPGA designs.
  • Place and Route Mode
    Specifies the type of Place and Route you want implemented in your design. Select an option from the drop-down list.
    • Normal Place and Route
      Runs PAR with effort levels you specify, or with default options.
      Note This setting is not available for Spartan®-6, Virtex®-5, Virtex-6, and 7 series devices.
    • Place Only
      Runs PAR with effort levels you specify, or with default options. The router does not run. The PAR process must be run at least once to use this option.
      Note This setting is not available for Spartan-6, Virtex-5, Virtex-6, and 7 series devices.
    • Route Only
      Runs PAR with effort levels you specify, or with default options. The placer does not run (current placement is kept). The PAR process must be run at least once to use this option.
      Note For Spartan-3, Spartan-3A, Spartan-3E, and Virtex-4 devices, only use this option if the design was placed by the Place and Route process. If the design was placed by the Map process using the Perform Timing Driven Packing and Placement property, do not use this option. Instead, use the Normal Place and Route option, which takes the placed design from Map and automatically runs routing only.
    • Reentrant Route
      Placement and routing are kept. The router runs one time in re-entrant mode using the existing routing if any as a starting point. The router is controlled by the effort level.
      Note This setting is for advanced flows and is normally not recommended.
    By default, this property is set to Route Only for Spartan-6, Virtex-5, Virtex-6, and 7 series devices, and Normal Place and Route for all other devices.
  • Place and Route Effort Level (Overall)
    Specifies the effort level you want to apply to the Place & Route process. The effort level controls the placement and route times by selecting a more or less CPU-intensive algorithm for placement and routing. Select an option from the drop-down list.
    • Standard
      Gives the fastest runtime with the lowest Place and Route effort. This setting is appropriate for a less complex design.
    • High
      Gives the longest runtime with the best Place and Route results. This setting is appropriate for a more complex design.
    By default, this property is set to High.
  • Placer Effort Level (Overrides Overall Level) (Advanced) (Spartan-3, Spartan-3A, Spartan-3E, and Virtex-4 devices only)
    Specifies the placement effort level used when placing your design. Specifying this property overrides the placement effort level set in the Place and Route Effort Level (Overall) property. Select a property from the drop-down list.
    • None
      No placer effort level is applied.
    • Standard
      Gives a fast runtime with lowest place effort. This setting is appropriate for a less complex design.
    • High
      Gives the best placing results but incurs the longest runtime. This setting is appropriate for a more complex design.
    By default, this property is set to None.
  • Router Effort Level (Overrides Overall Level) (Advanced) (Spartan-3, Spartan-3A, Spartan-3E, and Virtex-4 devices only)
    Specifies the router effort level used when routing your design. Specifying this option will override the router effort level in the Place and Route Effort Level (Overall) option. Select an option from the drop-down list.
    • None
      No router effort level is applied.
    • Standard
      Gives a fast runtime with lowest routing effort. This setting is appropriate for a less complex design.
    • High
      Gives the best routing results but incurs the longest runtime. This setting is appropriate for a more complex design.
    By default, this property is set to None.
  • Extra Effort (Highest PAR level only) (Advanced)
    Note The Extra Effort property is only available when the Place and Route Effort Level property is set to High.
    Specifies whether PAR spends additional runtime in an effort to meet difficult timing constraints. Select an option from the drop-down list.
    • None
      No extra effort level is applied.
    • Normal
      Runs until timing constraints are met unless they are found to be impossible to meet. This option focuses on meeting timing constraints.
      Note This setting may lead to very long runtimes. Design performance is not guaranteed to be better than when the Place and Route Effort Level property is set to High.
    • Continue on Impossible
      Continues working to improve timing until no more progress is made, even if timing constraints are impossible. This option focuses on getting close to meeting timing constraints.
      Note This setting may lead to very long runtimes. Design performance is not guaranteed to be better than when the Place and Route Effort Level property is set to High.
    By default, this property is set to None.
  • Starting Placer Cost Table (1-100) (Spartan-3, Spartan-3A, Spartan-3E, and Virtex-4 devices only)
    Specifies a placement initialization value with which to begin the Place and Route attempts. Each subsequent attempt is assigned an incremental value based on the placement initialization value. Select a number from 1 to 100.
    The number you choose corresponds to a cost table index and results in different Place and Route strategies. Cost tables assign weighted values to relevant factors such as constraints specified in the input file (for example, certain components must be in certain locations), the length of connections, and the available routing resources. Cost-based placement is described in the "PAR" chapter of the Command Line Tools User Guide (UG628).
    By default, this property is set to 1.
    Note If a number is specified for the Starting Placer Cost Table property in the Map Properties, the same Starting Placer Cost Table is used for the Place and Route process.
  • Ignore User Timing Constraints
    Controls the use of timing constraints during Place and Route. The primary method of specifying timing requirements is by entering them in constraints files (UCF and PCF). If this property is set to False (checkbox is blank), PAR places and routes in accordance with any timing constraints specified in the Physical Constraints File (PCF).
    If this property is set to True (checkbox is checked), timing constraints in the PCF are ignored when PAR runs. The setting of the Timing Mode property determines whether PAR automatically generates timing constraints to control placement and routing or runs without timing constraints.
    By default, this property is set to False (checkbox is blank).
    Note For detailed information about timing constraints, see the Constraints Guide (UG625).
  • Timing Mode
    Note This property is only available when the Ignore User Timing Constraints property is set to True (checkbox is checked).
    Specifies whether PAR generates timing constraints automatically to control placement and routing or runs without timing constraints. Select an option from the drop-down list.
    • Performance Evaluation
      This selection triggers the "Performance Evaluation" mode. In this mode, timing constraints specified in the Physical Constraints File (PCF) are ignored. Instead, timing constraints for all internal clocks are generated automatically and dynamically adjusted during PAR to increase performance. This mode is used to evaluate realistic performance targets for the design.
      Performance Evaluation is described in the "PAR" chapter of the Command Line Tools User Guide (UG628).
    • Non Timing Driven
      In this mode, timing constraints specified in the Physical Constraints File (PCF) are ignored but no timing constraints are generated automatically to replace them. This selection will make the Place & Route process run faster, but will not take into account timing constraints while generating the resulting output.
    By default, this property is set to Performance Evaluation.
  • Generate Asynchronous Delay Report
    Specifies whether or not to generate an asynchronous delay report when the PAR process is run. This report contains a list of all nets in the design and the delays of all loads on the net.
    By default, this property is set to False (checkbox is blank), and the report is not generated.
  • Generate Clock Region Report (Advanced)
    Specifies whether or not to generate a clock region report when the PAR process is run. This report contains information on the resource utilization of each clock region and lists any clock conflicts between global clock buffers in a clock region.
    By default, this property is set to False (checkbox is blank), and the report is not generated.
  • Generate Post-Place & Route Simulation Model
    Specifies whether or not to generate the post-place & route simulation model. When this property is set, the post-place & route simulation model is generated after the design is placed and routed. The property settings in the Simulation Model Properties dialog box are applied to the generated simulation model.
    By default, this property is set to False (checkbox is blank), and the simulation model is not generated.
  • Generate Post-Place & Route Power Report
    Specifies whether or not to generate a Power Report, which provides information about your design power consumption and thermal dissipation. Estimations are broken out per device resource, down to a single design module. Setting this option to True (checkbox is checked), is the same as running the Generate Power Data process.
    By default, this property is set to False (checkbox is blank), and the report is not generated.
  • Power Reduction
    Specifies whether or not to optimize routing to reduce power consumption.
    By default, this property is set to False (checkbox is blank), and routing is not optimized for power reduction.
    Note This option adds significant runtime to PAR.
  • Power Activity File (Advanced)
    Allows you to specify a simulation file, *.vcd or *.saif, to guide PAR when it optimizes the design for power reduction. This file is the output of a simulation run on the design. For power reduction, PAR uses this file to set frequencies and activity rates of internal signals, which are signals that are not inputs or outputs but internal to the design.
    By default, this property is blank (no file name).
    Note Simulation is the most accurate method of determining the exact activity rates. Back-annotated post-Place and Route simulation provides the best data for determining activity rates since it most closely represents physical implementation.
  • Enable Multi-Threading (Advanced) (Spartan-6, Virtex-5, Virtex-6, 7 series, and Zynq™ devices only)
    Note This property is not supported when using the Power Reduction or Ignore User Timing Constraints properties. It is not supported for use with SmartGuide™ or Partition design flows.
    Specifies whether to use multiple processors to enable multi-threading capabilities in the Router. When set to Off, one processor is used. When set to 2, 3, or 4, the software uses up to the number of processors specified.
    By default, this property is set to Off.
  • Other Place & Route Command Line Options (Advanced)
    Enter additional command line options. Separate multiple options with spaces. The options entered in this property appear first on the command line, before all other property options. Avoid setting duplicate property options.
    For more information about command line options, see the Command Line Tools User Guide (UG628).

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