Performing Timing Analysis - 2022.1 English

Vitis Model Composer User Guide (UG1483)

Document ID
Release Date
2022.1 English

Timing analysis can be invoked whenever you generate any of the following compilation targets:

  • IP catalog
  • Hardware Co-Simulation
  • Synthesized Checkpoint
  • HDL Netlist

To perform timing analysis in Model Composer:

  1. Double-click the System Generator token in the Simulink model.
  2. Enter the following in the System Generator token dialog box:
    • In the Compilation tab, specify a Target Directory.
    • In the Clocking tab, set the Perform Analysis field to Post Synthesis or Post Implementation based on the runtime vs. accuracy tradeoff.
    • In the Clocking tab, set the Analyzer Type field to Timing.
    Generated by Your Tool
  3. In the System Generator token dialog box, click Generate.

    When you generate, the following occurs:

    1. Model Composer generates the required files for the selected compilation target. For timing analysis Model Composer invokes Vivado in the background for the design project, and passes design timing constraints to Vivado.
    2. Depending on your selection for Perform Analysis (Post Synthesis or Post Implementation), the design runs in Vivado through synthesis or through implementation.
    3. After the Vivado tools run is completed, timing paths information is collected and saved in a specific file format from the Vivado timing database. At the end of the timing paths data collection the Vivado project is closed and control is passed to the MATLAB® /Model Composer process.
    4. Model Composer processes the timing information and displays a Timing Analyzer table with timing paths information (see below).

    In the timing analyzer table:

    • Only unique paths from the Simulink model are reported.
    • The 50 paths with the lowest Slack values are displayed with the worst Slack at the top, and increasing Slack below.
    • Paths with timing violations have a negative Slack and display in red.
    • The display order can be sorted for any column’s values by clicking the column head.
    • To show/hide columns, right-click any column head in the table and select/deselect the column name as required.

    • For a design with multiple clock cycle constraints, the Timing Analyzer can identify multicycle path constraints, and show them in the Path Constraints column. In that case, the Source Clock, and Destination Clock columns display clock enable signals to reflect different sampling rates.

    • You can cross probe from the table to the Simulink model by selecting a path in the table, which will highlight the corresponding HDL blocks in the Simulink model. See Cross Probing from the Timing Analysis Results to the Model.