Strand Routing Constraints
The following table describes the strand routing constraints.
| Constraint Name | Description |
|---|---|
|
This optional constraint specifies the number of strands that must be routed for strand nets. If this value is not given, the strand router will attempt to route the maximum number of strands based on the |
|
|
This optional constraint specifies the required exact spacing between strands, in microns, for the layer. If this constraint is not set, via-to-via pitch is used. |
|
|
This optional constraint specifies the required width, in microns, for individual strands on the layer. If this constraint is not set, |
|
|
This optional constraint determines the maximum distance, in microns, between two adjacent pins in a cluster. Strand routing can only route two clusters per net. Nets with greater than two clusters will not be routed. If this constraint is not set, 10*via-to-via pitch (maximum for all valid routing layers) is used. |
|
|
|
This optional constraint specifies that pins spaced less than or equal to the distance from each other on a multi-pin net are clustered together for strand routing. |
|
Limits routing to the specified layers. Set this constraint for single layer strands. |
Examples for Strand Routing Using Constraints
-
The
net_strandgroup,StrandGroup, is created for the selected nets. -
The
strandRuleSpecconstraint group is created. -
The strand constraints are set and added to
strandRuleSpec. -
strandRuleSpecis assigned to theStrandGroupnet group. - The selected nets are strand routed with 3 strands per net.
create_group -set [get_selection_set] -type net_strand -name StrandGroup
create_constraint_group -name strandRuleSpec -type userdefined
set_constraint -constraint numStrands -IntValue 3 -group strandRuleSpec
set_layer_constraint -layer M2 -constraint strandWidth -Value 0.1 \
-group strandRuleSpec
set_layer_constraint -layer M2 -constraint strandSpacing -Value 0.2 \
-group strandRuleSpec
set_layer_constraint -constraint maxClusterDistance -layer M2 -Value 0.5 \
-group strandRuleSpec
assign_constraint_group -net_group StrandGroup -group strandRuleSpec
strand_route -set [get_selection_set]
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