Synthesized Design and Implemented Design - 2024.1 English

Vivado Design Suite User Guide: Design Analysis and Closure Techniques (UG906)

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2024.1 English
  • Checks for DRCs related to the post synthesis netlist.
  • Checks for I/O, BUFG, and other placement.
  • Basic checks on the attributes wiring on UltraScale, GTs, IODELAYs, and other primitives.
  • Checks on connectivity such as, checking certain pins that are driven by synchronous signals.
    Note: Connectivity checks are not run on out of context designs
  • The same DRCs run taking into account any available placement and routing.
  • DRCs have four levels of security: Info, Warning, Critical Warning, and Error. Critical Warnings and Errors do not block the design flow at this point.

If there is a DRC violation with error level of severity it should stop the flow.

Steps of the implementation flow also run the DRCs, which can stop the flow at critical points. The placer and router check for issues that block placement. Certain messages have a lower severity depending on the stage. These are DRCs flagging conditions that do not stop opt_design, place_design , or route_design from completing, but which can lead to hardware failure.

Report DRC checks that the user has constrained the package pin location and the I/O standard for every design ports. If these constraints are missing, place_design and route_design issue critical warnings. However, these DRCs appear as an ERROR in write_bitstream. The tools do not generate a bitstream without these constraints.

The decreased severity earlier in the flow allows you to run the design through implementation iterations before the final pinout has been determined. You must run bitstream generation for a comprehensive DRC signoff.

The following figure shows the Vivado IDE graphical user interface form of Report DRC.

Figure 1. DRC Report

Click a DRC to open the properties for a detailed version of the message. Look in the Properties window to view the details. Most messages have a hyperlink for nets, cells, and ports referenced in the DRC.

Figure 2. Violation Properties Dialog Box

The DRC report is static. You must rerun Report DRC for the report to reflect design changes. The tool determines that the links are stale after certain design operations (such as deleting objects and moving objects), and invalidates the links.

Selecting an object from the hyperlink selects the object, but does not refresh the Properties window. To display the properties for the object, deselect and reselect it.

To create a DRC report in Tcl, run the command report_drc.

To write the results to a file, run the command report_drc -file myDRCs.txt.

Tip: For more information on report_drc, run report_drc -help.