Description

Description

This issue affects the following Versal SSIT devices when using Vivado 2022.2, 2022.2.1, and 2022.2.2.

• xcvh1582
• xcvh1782
• xcvp1502
• xcvp1552
• xcvp1702
• xcvp1802
• xcvp2502
• xcvp2802

• There is no impact to Non-SSIT Versal devices.
• There is no impact to Non-Versal devices.

A problem with the device modeling has been found with the Versal SSIT device connectivity related to redundant Laguna connections. In the affected versions, it is possible that Vivado can route a net using a Laguna routing node that is not meant to be used. The model was introduced in the 2022.2 release with the SSIT devices.

Impact

Designs impacted by this issue will see the following behavior.

• Cached routed Design Checkpoints (DCPs) can display incorrect functionality due to the redundant Laguna connection.
• Cached routed Design Checkpoints (DCPs) might now see Laguna routing failures (unroutes).
• Laguna detailed routing usage might differ and have potential Quality of Result fluctuations.

Identification

An attached Tcl script (check_redundant_sll_node_rev2.tcl) is available to be run on the final routed DCP used to generate a PDI. This can be sourced to determine if the current design is affected. 

1. Unzip AR000035155_identification_script.zip.
2. Copy the Routed DCP into the same directory as the Tcl script and unzipped .cfg files.
3. Open the Routed DCP and enter "source -notrace check_redundant_sll_node_rev2.tcl".
   1. If the design is affected by the redundant connections, then a list of the affected nets will be listed.
   2. If the design is not affected, the Tcl script will print "No Nets found in the dcp used suspected bad nodes"

If design checkpoints from previous Vivado versions are opened with Vivado 2023.1 or later, it will not have the invalid routing nodes, and will cause nets using these to be un-routed.

Below is an example of the critical warning:

CRITICAL WARNING: [Designutils 20-205] Net <Net_Name> was unrouted during load.