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Force db update/refresh regarding connectivity and pcell parameters

frankliu

Problem statement:

1. In layout XL create a (metal) rectangle and add a net name to it.

2. In skill add a (same layer) rectangle that abuts or overlaps this rectangle

3. Query the associated nets with this new rectangle in skill

   Result: its net name does not get updated

   Expected result : the net name associated with 1.



Note:

If instead of 2. you manually create a rectangle from the layout editor, then the query in 3., works as intended.

If I put a breakpoint between 2 and 3 then 3. works

If I add a dbSave between 2 and 3 then 3. works



I would like to avoid using dbSave, since this is too heavy handed and slows down my script.  I would like the connectivity information to be updated at the end of 2.  Please let me know if there is a way of updating this information.



Note:

In the title I also mention pcell parameters, this also happens with pcells, I know that in some cases you have to call the callback function associated with a parameter in the pcell, and I have, but a similar situation happens.  For example in a transistor pcell, when I change the number of fingers, and then query for the geometry of the poly, I don't get an updated number, and as in the connectivity example above, if I insert a breakpoint or perform a dbSave then the information gets updated.  Clearly something must be called within dbSave or when restarting from a breakpoint to update the connectivity / cell parameters.



Sorry if this is not clear, please let me know if you need further details.

Parents

  • Hi Frank,

    The feature of updating abutted or overlapping shapes is an interactive Layout XL feature, and thus it does not occur for non-interactive SKILL code. I believe that this is part of the (VLS-XL) connectivity extractor that is keeping track of connectivity and either warning of shorts, for example, or updating these abutting/overlapping shapes. I don't think that there is a public SKILL API to access this functionality either. To emulate this (simplistically, at least) you would need to look at abutted or overlapping shapes to your new object and obtain connectivity from these and apply back to the new shape. This shouldn't be too hard, but could slow down the code because of the additional search needed (dbGetOverlaps, dbProduceOverlap, dbShapeQuery ...)

    Hope this helps you!

    Best regards,

    Lawrence.

Reply

  • Hi Frank,

    The feature of updating abutted or overlapping shapes is an interactive Layout XL feature, and thus it does not occur for non-interactive SKILL code. I believe that this is part of the (VLS-XL) connectivity extractor that is keeping track of connectivity and either warning of shorts, for example, or updating these abutting/overlapping shapes. I don't think that there is a public SKILL API to access this functionality either. To emulate this (simplistically, at least) you would need to look at abutted or overlapping shapes to your new object and obtain connectivity from these and apply back to the new shape. This shouldn't be too hard, but could slow down the code because of the additional search needed (dbGetOverlaps, dbProduceOverlap, dbShapeQuery ...)

    Hope this helps you!

    Best regards,

    Lawrence.

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