Re-number GDS layers

Hi,

Is there a way to re-number the GDS layers in an existing design? For
example, my poly2 is GDS layer 3 and I would like to change that so that
I may stream in other designs without having to use a GDS layer map
table. The box which specifies the layer number is grayed out under tech
file -> edit layers.

I have tried dumping the tech file, editing the layer number in an
editor, and re-loading the modified tech file. This DOES change the
layer number when I look under tech file -> edit layers, however I can
no longer see that layer in my existing layouts. If I go back and change
the layer number back to 3, (dump and load) I am able to see the layer
again. What's the "correct" solution?

P.S.
I really don't want to stream out the entire design and stream it back
in with a layer map table.

Thanks for your help,
Raf

 

Have you tried changing the streamLayers information in the technology file
instead? The layer number is how it is actually represented in the database, so
you don't really want to change that.

The streamLayers class in the tech file allows you to have the mapping
between stream layer/datatype numbers and Cadence layername/purpose
defined, and avoids the need for a layer mapping file.

Andrew.

 

Hi Andrew,

Are you talking about the following part of the techfile?:

layerRules(
streamLayers(
;( layer streamNumber dataType translate )
;( ----- ------------ -------- --------- )
( ("Metal1" "drawing") 56 0 t )


I found that if I changed this number only things would not stream in
properly. If the stream had a layer x for Metal1 it would merge with
layer Number x instead of being translated to 56 first. Was I doing
something wrong?

So the way this should be done and work is that each layer in the
techfile -> edit layers should have 'my' layer number which doesn't
really matter, and a stream translate number. When I stream in, it
checks what to translate a particular layer to (stream translate number
to my layer number). Is this correct?

Is there any way to get a listing of all the layer numbers used in a
particular stream? I thinking that maybe I had the translations wrong.

Thanks,
Raf

 

Is there any way to get a listing of all the layer numbers used in a

Look in your PIPO.LOG file.

One question from my side why do you not want to use a
layer mapping file, this would probably the best way to
do get what you need?

Bernd

 

Personally I've always preferred to have this in the tech file, because it
avoids having to maintain another file, and users having to remember to fill it
in (yes, I know you can make it so that streamInKeys/streamOutKeys is set to
that the default value of the layer map file is filled in).

How this works is well covered in the Design Data Translators manual.

Essentially it's just a layer map file but in the tech file. The Cadence layer
number is then essentially irrelevant - the tech file data tells it what stream
layer number to map to which Cadence layer name/purpose (and vice versa
for stream out).

Andrew.

 

I fully agree with you Andrew, but the advantage of an external
layer mapping file is that is is ASCII and you don't have to
dump and load it every time you do some experimental things with
your layer mapping e.g. stream in layouts with strange layer
datatpye settings which you want to map to your specific layers.

And this it what these postings sound to me.

Bernd

 

Hi,

Thanks for your suggestions Andrew, they helped and I have resolved the
problem.