useAltergroup

Hey All,

I have been messing around with ic5.10.41.169, and when I run it with
a third party simulator I get warnings about the cdsenv files
associated with it. One specific warning is about useAltergroup. I
did a search on cdsdoc and didn't come up with much except how to set
useAltergroup. Does anyone know exactly what altergroups are? Is
this something new to ic5.10.41?

Thanks,

Dave

 

altergroups were added in spectre back in IC443, I think. They allow
you to change several things at one time when doing alters in spectre
- for example, you can substitute one section of models for another in
a library file.

They are used by the corners tool. However, occasionally some model
files don't work (either because they contain models that don't
support altergroup, or because of front-end problems which have
probably been solved with the new front end in IC5141).

You can get the corners tool to not use altergroups by using:

spectre.envOpts useAltergroup boolean nil

in your .cdsenv file, or by using:

envSetVal("spectre.envOpts" "useAltergroup" 'boolean nil)

in your .cdsinit.

However, this is a spectre environment setting; I'm not sure why a
third-party simulator should be complaining about it.

Regards,

Andrew.