Need to get routing layers info from tech db

RE: Need to get routing layers info from tech db

Utkarsh03 — Thu, 04 Mar 2021 15:48:15 GMT

Got that!! In my techfile we have a contraint group called "default" and valid layers is inside that. Thankyou Andrew, above commands work perfect.

RE: Need to get routing layers info from tech db

Andrew Beckett — Thu, 04 Mar 2021 15:37:18 GMT

Well, I'm pretty sure you're going to need validLayers in whichever constraint group you're using for routing (it may not be LEFDefaultRouteSpec). Say it's called something else, you can do this:

cg=cstFindConstraintGroupIn(tf "LEFDefaultRouteSpec_gpdk045")

then:

cstFindFirstConstraint(cg "validLayers")~>value

cstFindFirstConstraint(cg "routingDirections" list("Metal3"))~>value

This is assuming that there's validLayers and routingDirections defined within the constraint group in question.

Andrew.

RE: Need to get routing layers info from tech db

Utkarsh03 — Thu, 04 Mar 2021 15:27:50 GMT

Thank you Andrew for your answer. I just verified that LEFDefaultRouteSpec does not include any validLayers constraint within it. That is why probably I am getting nil. Can you please suggest other method to extract Routing Layers info from the tech db?

Utkarsh

RE: Need to get routing layers info from tech db

Andrew Beckett — Thu, 04 Mar 2021 14:46:27 GMT

Hi Utkarsh,

This article indicates that the techGetPr* functions are for legacy support these days and ideally you should go to the constraintGroups instead: API techGetPrRoutingLayers(tfId) does not work with ITDB

However, if techGetPrRoutingLayers returns nil, then that means you do not have a LEFDefaulteRouteSpec constraint group, or it doesn't have a validLayers constraint within it. The routing directions information doesn't come from a routingDirections constraint within that constraint group (rather bizarrely) but from the routingDirections specification within the layerRules section (the documentation does say this). The techGetPrRoutingDirection function only retrieves from the routingDirections in layerRules if the LEFDefaultRouteSpec constraint group exists though....

Andrew.