Encounter does not stream out all cells into a GDS

I believe you need to use streamOut's "-merge" option and supply it with the gds file(s) that describe the contents of the standard cells.

Hi Bob,

Those GDS files may not be available. The standard cells are introduced to the Encounter by LEF and lib files.

Do you think i need to import the LEF and lib files into the cadence too?

if yes, isn't it something redundant that occupies a lot disk space?, because their library is already defined and available in the cds.lib.

Ali

Hi Ali,

If the GDS files aren't available, then within Virtuoso the contents of the standard cells should be defined within a Virtuoso library in you cds.lib path. It sounds like that is the situation you have now, but you're seeing "red boxes". Are they empty? Or if you hit "shift-f" in Virtuoso do their contents become visible?

For Calibre-DRC, if the gds of the standard cells aren't available, you might want to try streamOut's "-outputMacros" option that will stream out the contents of the standard cells as defined in the LEF abstracts rather than what is within the gds.

-Bob

Thanks Bob,

hitting "shift-f" showed markers with crossed diameters. therefore, the cell were not created in the layout.
I recreated the GDS by using -outputMacros, then it solved the error and now GDS includes the standard cells when imported to the cadence.
If you don't mind, i would like to ask another question.
What is difference between merging the GDS files and using -outputMacros when streaming out the design from Encounter?
Also, what shortcut key does the reverse of "shift-f"?

Thanks again,
Ali

-outputMacros uses the LEF abstract geometries for the standard cells which usually includes only pins and blockages to reduce the size of the data set as compared to gds which contains full detail of the standard cells. The risk you run when running geometric verification with LEF abstracts instead of gds is that the LEF abstract doesn't capture some detailed nuance that the gds contains and a violation can sneak through. The purpose of creating abstracts is to simplify the implementation tool's job so it doesn't have to consider every little geometry.

In Virtuoso, I believe the reverse of "shift-f" is "ctrl-f".

Hope this helps,
Bob

Ali,

I would not recommend running physical verification (DRC/LVS/etc.) on a gds that uses the LEF data instead of GDS data. You are likely to get a lot of violations that you would not see with the full layout. The whole purpose of streaming in to Virtuoso is to pick up the cell layouts. If you don't see them in the Library Manager of Virtuoso, that's the problem. If you do see them but they are not getting included in your design when you stream in the FE gds, then it's likely a problem with the stream in setup. I'm not sure what your design flow is, but hopefully this helps.

- Kari

Hi Kari,

I am running Encounter using LEF and lib files of cmos90nm technology. The library of cmos90nm is defined and available in the library manager of Virtuoso (layout/symbole/abstract/...). When i finished the place&route, i exported the design into a GDS file. When the GDS file was imported in to the Cadence, PIPO.log showed some warrning as follow:

CellView Rectangles Polygons Paths Ellipses Labels Instances Arrays Dots
******************************************************************
decoder576/layout 1642 0 2389153 0 2 3171777 0 0
(BFLVTX2/layout) -- (referenced, but not defined, no data created).
(CTBUFLVTX6_0/layout) -- (referenced, but not defined, no data created).
(CTBUFLVTX12_0/layout) -- (referenced, but not defined, no data created).
.
.

so, Bob told that the GDS of standard-cell library should be merged into my design when streaming out the design from Encounter. But i am not given such GDS files. mayby CMC ot STM doesn't support it.

Is there any method to generat the required GDS files?
Or do I have any mistake in using tools?

Thanks,
Ali

Ali,

How do you stream in to Virtuoso?

If you use the GUI, then make sure you click on the Options, and turn on Retain Reference Library (No Merge). I know it sounds counter-intuitive, but give it a shot.

If you use a set of keys and the command line (pipo strmin si_keys), then make sure refLib in si_keys is set to t.

Let us know how it works - there is another thing we can try if it doesn't.

- Kari

Kari,

Perfect, I think it worked by turning "Retain Reference Lib" on. No other warrning.
Now, I see the red boxes in the layout, which include the layout of std-cells (using "shift-f").

Thank you very much indeed,
Ali