Known Problems and Solutions in Virtuoso Automated Placement and Routing Solution
This document describes the known issues with Virtuoso® Studio Automated Placement and Routing Solution and suggests the workarounds for these issues. Each issue is identified by a Cadence Change Request (CCR) number.
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CCR 2807265: Cross via QoR in customer data
Description: There is an issue with stacks of three or more vias not being properly detected or fixed.
Solution: This is a rare occurrence and will need to be manually fixed if the user needs these stacks aligned.
CCR 2789954: Which router is advised for mix mode designs
Description: Currently, none or the routers support mixed designs, which contain a mix of devices, standard cells, and small blocks in the same hierarchy.
Solution: Separate the standard cells and devices into different designs.
CCR 2532962: validLayers violations are not reported
Description: Some constraints such as validRoutingLayers are incorrectly applied to the design default constraint group instead of the UserDefinedDesignDefault constraint group. This problem can occur with any design style through the use of the Setup tab in the Routing assistant with user modifications to the Layer Settings for Bottom and Top Layer. Also, when the user saves the design, these constraints are captured in the disk data for that design and becomes persistent. These existing constraints can override values intended for the foundry constraint group while running the DR checking.
Workaround: If anomalies are found while running verification, use Constraint Manager to delete the constraints from the design default constraint group. The solution is being developed and will be available in a future release.
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