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CAS Incomplete Net problem

Hello,

I am using the CAS from layout GXL. I found it very useful tool to guide my layout routing. But I am facing a problem when I do the layout of two blocks. I took a snap of part of the design where u3 connection from the second layout cell need to be connected to the u3 net of the first layout cell. The CAS always suggest to connect to the exactly on the pin to remove the missing connectivity message, while I managed as you see from the image to connect the two u3 nets on different place and the design passed the LVS.

It looks like CAS in hierarchical design only actively check for pins not for net

Thank you in advance

Regards

Alex Soyer over 4 years ago

Hello Senan,

Maybe you have done an off pin connection ( connecting from top level to lower level shapes directly and not going through the pin).

Could you try to run the connectivity extractor with a hierarchy depth of 1?

Click on menu "Connectivity"> "Extract Layout" then in the new form click "Options" then set the "Extract Connectivity Level" to 1.

Thanks,

Alex
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Senan over 4 years ago in reply to Alex Soyer

Dear Alex,

Thank you for your help

Your suggestion is perfectly working, I had no idea about the "Extract Layout", its looking helpful tool,

could you please also refer me to some materials or cadence lectures to read more about it.

Thank you once again

Regards
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Alex Soyer over 4 years ago in reply to Senan

Dear Senan,

CAS: Check Against Source is then engine comparing your schematic and your layout and it is going to report any differences (parameters, connectivity on devices pins, etc..).

Connectivity Extractor: it is going to look at the physical connectivity and propagate the connectivity along the shapes to detect if you have opens or shorts.

I think this RAK (Rapid Adoption Kit) on the basics of Layout XL should be a good starting point:

https://support.cadence.com/COSAgreementPage?artId=a1Od00000066Mz6EAE&id=069d0000003H2jLAAS&sq=null

Thanks,

Alex
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Senan over 4 years ago in reply to Alex Soyer

Thank you Alex,

That is very useful, I am going to cover this nice material

Have a nice time

Best Regards
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