Enabling/Disabling Routing on a Layer
To enable or disable routing on a layer, set the limitRoutingLayers constraint using the set_constraint command. For example:
set_constraint -constraint limitRoutingLayers -groups_routeSpec-LayerArrayValue {s_layerName…}
The layers given by this constraint are ANDed with the layers given by the validRoutingLayers constraint to determine which layers to route on.
In the following example, the design’s valid routing layers are read in as M1, M2, M3, M4, and M5 for the rs1 route spec, and the equivalent Tcl command is given as:
set_constraint -constraint validRoutingLayers -group rs1 -LayerArrayValue {M1 M2 M3 M4 M5}
For this example, the following command causes the router to use only M2 and M3 layers when routing nets on the rs1 route spec.
set_constraint -constraint limitRoutingLayers -group rs1 -LayerArrayValue { M2 M3}
To enable routing on all valid routing layers, unset the limitRoutingLayers constraint. For example:
unset_constraint -constraint limingRoutingLayers -group rs1
Related Topics
Preparing the Routing Environment
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