FreePDK15 setup/layout problem

Hi Greeny,

This PDK is pretty primitive and has lots of stuff missing. It seems to have quite a lot of fixed cells for vias in the NCSU_TechLib_FreePDK15 library, but these aren't parameterised. You could add these to the customViaDefs - e.g.

(MINT3_MINT2 NCSU_TechLib_FreePDK15 MINT3_MINT2 layout MINT2 MINT3 0.0)
(MINT4_MINT3 NCSU_TechLib_FreePDK15 MINT4_MINT3 layout MINT3 MINT4 0.0)

but this will be a bit rubbish because they are not parameterised. I'd suggest it would be better to fill in the stdViaDefs based on the relevant rules for those vias (I didn't spend time trying to figure out what is appropriate).

You'd then want to add a validVias rule into the virtuosoDefaultExtractorSetup constraint group in the tech file so that it knows which vias to use.

Or you could contact whoever maintains this Free PDK.

Andrew.

Hi, dear Andrew,

Thanks a lot for your reply.

I have been checking the discussions on the forum but I am still confused by what you are referring to by the tech file(The cdsDefTechLib?) I have been searching through my directories to find a file which contains the text "virtuosoDefaultExctractorSetup" but failed. I am attaching my cdslib file so that you could specify more on how I can trace the tech file and find it in my library. 

Thank you !

Greeny

Hi, dear all,

I have been looking at the discussions on the forum which talk about the techfile of the PDK, but I am still confused by what you mean exactly by the techfile. I am having this problem of not being able to add vias onto the layout editor. The error tells me to define my vias in the following constraint group which is supposed to be in the techfile. If any of you could help me on how to trace the techfile and locate it in the file system, that would be really helpful.

Thanks a lot in advance.

Greeny

I've no idea why you posted the same question again separately since this was clearly part of the same issue you had before. Please don't do this - the forum guidelines ask you not to (it just irritates people). So I joined it to the same thread.

Anyway, the technology database is in the NCSU_TechLib_FreePDK15 library, and is a binary file called tech.db. This was created from the FreePDK.tf that you asked about earlier - it's in the cdslib/setup dir (from memory - I don't have my work computer handy to check). That FreePDK.tf has the constraint group virtuosoDefaultExtractorSetup defined within the tech file.

If you are going to try to fix this yourself, you'd modify the file (or a copy of it) and then use Tools->Technology File Manager and then load the ASCII tech file you've created into the NCSU_TechLib_FreePDK15 to update the tech.db in that library (don't forget to use the Save button on the Technology FIle Manager afterwards to ensure it gets saved before you quit Virtuoso).

Regards,

Andrew.