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

Hi Lei,

Just to make a suggestion.

for 1 I would rather get the IO  instance origin info (intsance->xy) and the transformation (intance->transform) instead of relying on a specified layer bounding box.

then as you walk through all the IO instances, just simply instantiate the pad head instance, using the info on number 1 you should be able to calculate and placed them correctly relevant to the IOs.

best regards -lrlsk

Thank you for your reply!

But I still had some questions with your suggestion:

I tried to get the instace attributes with programs shown as below:

cvId = dbOpenCellViewByType(libname cellname "layout")

foreach(inst cvId~>instances

println(inst~>bBox)

)

I could only find bBox of instance, but not instance origin and transform(I don't know what the function of transform is).

Meanwhile, if I instantiate mosaic instances in the cellview, I could not get each bBox of them. Then how could I get the information to calculate each IO's position.

 Thanks

Lei 

Hi Lei,

For an instance, you can use inst~>xy (to get origin) and inst~>orient (to get the orientation) or inst~>transform to get both together (along with a magnification - don't use this, since it's obsolete in OA). This is clearly covered in the documentation on database objects, and can be found by looking at inst~>??

Mosaics are a little complex, but you find mosaics by looking at cvId~>mosaics (which has a bBox). An example of dealing with mosaics can be found in Solution 11328674

Regards,

Andrew.

I have limited access to cadence online support right now. Is it possible that you send me the solution through email(reneezl26@hotmail.com)?

Thank you so much!

Lei

I have limited access to cadence online support right now. Could you send the solution to me through my email (reneezl26@hotmail.com)?

 Thank you very much!

Lei

 Rather than going through all the instances in your design,sort through the instance headers to find the cells that match yourIO cells. The instHeaders have a pointer to the instances made by those masters. You will be processing much fewer objects. For regular cells there is one instHeader for each master, for pcells there is one instHeader for the superMaster and one for each variant.

 cvId = deGetEditCellView()
listOfIOCells = list( "IO_cell_1" "IO_cell_2"...)

ihList = setof( ih cvId~>instHeaders   member( ih~>cellName listOfIOCells ) )

foreach( ih ihList
  foreach( inst ih~>instances

;; Process instances here

) )

 Hi Renee,

 I totally agree to Austin and about your question on what's the importance of getting the IO origin and transform, here is my idea behind that, First I would measure the displacement from the IO->xy to the Pad origin (where you want it to be placed) the IO-orient will give you the idea whether it is rotated, mirroredX or mirroredY etc. So for each instance of IO you will know how to add this relative displacement when placing the Pad head. Of course if you have several flavors of IO instances then you just need to build each case in your code.

For mosaic, it is the same story, you can olso get the mosaic number of rows or columns and the origin where the master is located.

BR  lrlsk

Hi Renee,

 Sorry because I couldnt see your picture, but I think this is how you should do it

1 you get the relative displacement (x and y) of the instance origin of the IO to the origin of the Pad Head

then for each IO instance get the tranformation and mirroring and assign the same property for their own Pad head so you would only worry about the rotation.

for Example at R0 the displacement is X and Y

then at R90 x becomes y and y becomes -x, at R180 x becomes -x and y becomes -y lastly at R270 x bexomes -y and y becomes x

you cancelled the effects of mirroring like for example R0MX because you have assigned same mirroring for the Pad Head.

Thanks for your advice.

 I still have some problems with this pad head problem:

If the IO instances are placed at lower level of the design and I could only add pad heads at the top level. How can I go through all the instances from top to bottom view and find these IO cell instance?

 Thanks!