InTime Software

How to exclude certain timing slack types?

115 views February 27, 2017 December 27, 2021 harnhua 0


InTime considers every timing slack type in its calculation of TNS (Total Negative Slack). In the following screenshot (Figure 1) from the Quartus-II software, the Design-wide TNS consists of Setup and Recovery slack components for this design. ScreenFigure 1: Timing results

If Recovery slack is counted, the TNS is -94.725 + -9.255 = -103.98 ns. Otherwise, the TNS is -94.725 ns. By default, InTime considers all slack components when calculating the TNS (see Figure 2 below). with_recoveryFigure 2: TNS that includes Recovery slack

However, some users may not care about Recovery slack (or other slack types) at all, and think that the TNS should include only Setup and Hold timing. ### Solution:

In InTime\'s GUI, go to File > Settings > Vendor Toolchains > Intel Quartus-II/Quartus Prime and uncheck the appropriate item. ScreenFigure 3: Include Recovery and Removal slack

ScreenFigure 4: Exclude Recovery and Removal slack

Alternatively, in the Tcl console, enter:

<pre left="" style="text-align:">flow set goal_quartusii_enable_recovery_time_in_tns false

In subsequent results, the TNS calculation will be adjusted accordingly (see Figure 5). without_recoveryFigure 5: TNS that excludes Recovery slack

Applies to:

  • Quartus-II
  • Linux Operating System
  • Windows Operating System

Knowledge Base ID: 201702071 - Last Review: Feb 07, 2017 - Revision: 1.0

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