Layout: from Encounter to Virtuoso

Hi Francesco,

The preferred method for exporting a database from Encounter to Virtuoso is through the use of OpenAccess (IC 6.1.3) or DEF (IC 5.1.41 and DEF 5.5). This will resolve your layer mapping issues and will retain the connectivity information in the database.  The resulting cellView may be modified with VCE and returned to Encounter for an ECO. Using GDSII eliminates this ECO flow option.

If you want to continue with the GDSII option, then the layer map file used with Encounter streamOut should be modified such that it aligns with that used for Virtuoso.  Please consult the Encounter product documentation for details on the format of the mapfile used by Encounter.  What you have included in your e-mail transcript is a generic map file based upon you LEF.

Hope this helps,

Marie Kunesh 

 Hi Marie,

 thank you for your aswer.

 As you said, I found the OpenAccess database as a quite good method to export layout from Encounter to Virtuoso. I still have a couple of question about this new method:

1) When I use the "Import Design" GUI in Encounter and select Advance tab there is a OpenAccess form. In the fields "Reference Libraries", "Abstract view names" and "layout view names" I put (in a generic way) respectively: cmrf8sf Arti2009DM, abstract and layout. I don't use the "Use OA netlist" because I think I need to use this option only if I already have an OA netlist. Am I right?

 2) After importing the design, I P&R it. Then, I go to Design --> Save Design As --> OA: here I can save the design inside a library that I have to define previously (before any import) in a lib.defs file. The question is: where do I have to put this file? The situation is the following: Encounter is running in a directory called "encounter" while I want to save the design in a directory called "Francesco_1", where I already have the schematic view of my design. So, in the lib.defs file, I've define the path of Francesco_1 directory (together with the path to cmrf8fs, Arti2009DM libraries) and I put this file in the Encounter directory. Is this reasoning correct?

3) After saving my design in Francesco_1 I can open the layout view. The problem, here, is that I can see the routing and the power/ground rings BUT all the cells (flip-flop, inverter, etc...) are using the abstract view! If I want to see the complete layout (with n-well, p-well, internal routing of the standard cell) I have to select a cell, press 'Q' (the Property window pop-up) and change the view from abstract to layout. Is there a way to do this thing automatically for all the cells? 

Thank you very much for help!

Francesco.  

Hi Francesco,

 1) The OA netlist field is used only when an existing cellView contains the netlist information. This could be done with a cellView which was created with VLS-XL or with Encounter.  Most designs start with a Verilog netlist.

 2) The lib.defs must be in your working directory: "encounter".  It contains the pointer to "Francesco_1" such that saveOaDesign will be able to find its path.

3) The Encounter saveOaDesign command does not enable remastering abstracts to layout. To do this, you can use Encounter's  oaOut command along with  "-leafViewNames {layout}" option.  If you want to restore the OA cellView with Encounter, you will need to use both saveOaDesign and oaOut commands.  Alternatively, you can use saveOaDesign and then use Virtuoso to remaster the abstracts to layouts.

Hope this answers your questions,

Marie 

Thank you very much for your help, more or less the problem is solved now :)

 Francesco.

I'm having two issues with encounter and virtuoso layouts when saved and read in OA. 

My setup is virtuoso 6.1.3 and soc encounter  7.1, techno AMS kit 4.0.

 As commented before, to get the full layout view I save OA using the option -leafViewNames {layout}, but when I do this I obtain misplaced standard cells with lots of DRC errors (they seem to be a little bit moved). I can export without the option and change the view in virtuoso without this kind of errors, but it should be more easily if I could just export directly.

 The second issue is I don't get the pins in virtuoso, how do I get them??

Albert

Albert,

Can you log this as a service request with Cadence Customer Support?

I thought the problem might be due to a mismatch between the LEF abstract views and the views in Virtuoso - but that doesn't sound likely because the problem doesn't occur if you remaster the views within Virtuoso.

Regards,

Andrew.

 Ok, I will try

and regarding the I/O pins?? why I can't see them in virtuoso (the name of the nets is correct but the pin is not present)?

Albert

 Albert,

I don't know. I'd have to try it to find out, and quite honestly I don't have the bandwidth today to try this (it's not something I'm that familiar with, to be honest, as it's outside my usual field of expertise). So ask at the same time you file a service request.

Regards,

Andrew.

Hi Albert,

Concerning the move of the cell when switchingfrom abstract to layout it could be due to some origin mismatch between abstrcat and layout view.

Could you please check on the Navigator if the pins are there ?

If they are not visible it could be due to placement status (invisiblke if placement status = unplaced) or due to missing definition of the layer in term of display in that case you can run oa2dfII on your library to fix teh problem.

I hope it helps,

Alex

 Hi Alex,

 thanks for you ideas.

The origin on abstract and layout view are the same, so that's not the problem... it's strange because this misplacement seems to be only present on some of the HVRING cells of AMS, so perhaps the problem is on the ams script that generates this ring...

On navigator pins are there, I think the problem is that AMS rules for ASSURA only detect pins if they have a LABEL on the PIN layer, which is not created on the oaOUT.

Albert