How to compute the bounding box of a cell in a hierarchical design

Do a recursive descent of all the instances in the design, and look for the IO cells at each level. As you descend, you can keep track of the overall transformation (by looking at inst~>transform) and you can then concatenate all the transformations (using dbConcatTransform). You can then use this concatenated transformation to map any coordinates within the IO cell back to the top level cellView, and thus know where to place the "pad heads".

There are quite a few examples of using recursion to visit all cellViews in a layout on http://support.cadence.com and similarly examples of using dbConcatTransform.

Regards,

Andrew.

My idea is this:

It will go down from top level to bottom level automatically and check if there are IO cells at certain level.

I used Andrew's code and modified it to realize the function:

procedure(tra_v1(cellView levels transform)

; the variable levels is an indication of current level

  foreach(inst cellView~>instances

 if(inst>cellName=="VSSIO" then

       println("find it")

       println(levels)

       else println("haven't find it")

       );end if

  println(inst~>cellName)

  println(inst~>transform)

  tra_v1(inst~>master levels-1 dbConcatTransform(transform inst~>transform))

  ) ;end foreach

)

procedure(hier_v1()

       cvId = deGetEditCellView()

       ident_transform = list(0:0 "R0" 1.0)  

       levels = dbGetMaxHierDepth()

       tra_v1(cvId levels ident_transform)

);end procedure

But there are some problems with this program:

• 1. It indeed prints some transform information of cells, but it terminates and reports that:

Error: dbConcatTransform: invalid transform - nil

• 2. I find that this program traverses only one cell from top level to bottom level which means that if there are instance I1 containing I2(containing I2_1) and I3(containing I3_1), it only reports transform information like this:

I1 (0:0 "R0" 0)

I2 (10:10 "R0" 0)

I2_1 nil

I would like that the program traverses both instance I2 and I3 from top to bottom level.

Thanks

Quick answer - the chances are that this is because you have mosaics in the design and are trying to look at the mosaicInst instances. You would need to filter out any instance with objType of "mosaicInst". Handling mosaics will get somewhat more complicated - so I'm hoping you don't have any mosaics of the cells you're trying to locate and so can safely ignore iterating over cvId~>mosaics in this case.

Regards,

Andrew