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Valid layers vs. normal layers using SKILL

ToMWUT
I’ve got a problem with lpps on my layout. When I’m trying to display them using cv~>lpps and then lpps~>layerName and lpps~>purpose I get one result. But when on the other hand I’m displaying all valid layers due to technology file of my project I’m unable to get those lpps which I obtained using first approach. What am I doing wrong? I put my SKILL code below:
 
foreach(lpps cv~>lpps
            printf( "Name:  %s purpose %s \n",  lpps~>layerName,    lpps~>purpose)             
            );foreach
valid=leGetValidLayerList(techGetTechFile(cv))
println("Valid Layers:")
foreach(lpps valid
            printf( "Name:  %s purpose %s \n",  car(lpps),    cadr(lpps))                       
            );foreach
 
Does it mean that layers used in my layout aren’t valid layers due to technology file? What’s the difference between a valid layer and a normal layer?
Some additional information: I’m talking about a layout which I obtained after the extraction process – it’s quite obvious that I would not be able to draw those layers using some editing tool, because they are not valid… or am I wrong?

  • ToM,

    A valid layer is simply a layer which you are allowed to draw shapes on. Put another way, it means that the layer shows up in the LSW (there are other ways to further filter the layers in the LSW, but historically this is it).

    You can create shapes on any layer/purpose combination using SKILL though, or other means - for example an extracted view. It simply means you can't draw it with the layout editor.

    So it would be quite usual to find lpps in your layout (particularly if it's an extracted view) which aren't valid layers. Often net purposes are used in extracted views rather than drawing purposes.

    So to summarize - valid layers are just a subset of the complete set of layer purposes.

    Regards,

    Andrew.

  •  That's what I thought... Thanks Andrew :)

     ToM

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