oaPreferredRoutingDirection

The oaPreferredRoutingDirection constraint is specific to the default constraint group of an oaAreaBoundary. The preferred routing direction outside the oaAreaBoundary is specified in the technology database. The preferred routing direction can be one of the orthogonal or one of the diagonal routing directions.

oaPreferredRoutingDirection Quick Reference

Constraint Type	Layer
Value Types	`IntValue`, `StringAsIntValue`
Database Types	Design, Technology
Scope	area boundary, design, foundry
Category	Routing

Value Types

oaPreferredRoutingDirection constraints have an IntValue or a StringAsIntValue that is input as a string value and stored as an integer value as shown in the following table.

oaPreferredRoutingDirection Values

String	Integer Value	Preferred Routing Direction:
`notApplicablePrefRoutingDir`	0	Preferred direction cannot be determined
`nonePrefRoutingDir`	1	All directions allowed
`horzPrefRoutingDir`	2
`vertPrefRoutingDir`	3

Examples

In this example, applying the myRoutingLayerOverrides constraint group to a bounded area the following routing direction will be set within that area:

Metal1 to vertical
Metal2 to horizontal

Metal3 to none, thereby allowing it to take any routing direction

Format	Example
Tcl	set_layer_constraint -constraint oaPreferredRoutingDirection \ -layer Metal1 -StringAsIntValue vertPrefRoutingDir \ -group myRoutingLayerOverrides set_layer_constraint -constraint oaPreferredRoutingDirection \ -layer Metal2 -StringAsIntValue horzPrefRoutingDir \ -group myRoutingLayerOverrides set_layer_constraint -constraint oaPreferredRoutingDirection \ -layer Metal3 -StringAsIntValue nonePrefRoutingDir \ -group myRoutingLayerOverrides
Virtuoso	constraintGroups( ("myRoutingLayerOverrides" routingDirections( ("Metal1" "vertical") ("Metal2" "horizontal") ("Metal3" "none") ) ) )

Format

Example

Tcl

set_layer_constraint -constraint oaPreferredRoutingDirection \
  -layer Metal1 -StringAsIntValue vertPrefRoutingDir \
  -group myRoutingLayerOverrides
set_layer_constraint -constraint oaPreferredRoutingDirection \
  -layer Metal2 -StringAsIntValue horzPrefRoutingDir \
  -group myRoutingLayerOverrides
set_layer_constraint -constraint oaPreferredRoutingDirection \
  -layer Metal3 -StringAsIntValue nonePrefRoutingDir \
  -group myRoutingLayerOverrides

Virtuoso

constraintGroups(
   ("myRoutingLayerOverrides"
     routingDirections(
              ("Metal1" "vertical")
              ("Metal2" "horizontal")
              ("Metal3" "none")
              )
    )
)

Virtuoso Space-based Router Constraint Reference
Product Version IC23.1, June 2023