Re: Question about LEF and DEF support

[Steven Rubin]

>        I want to read-in a previously generated design to
>         test out the area/maze routing features in electric.
>         I have both the full LEF (with technology, sites, macros,
>         rules etc...) as well as the corresponding DEF with
>         components, nets and special nets sections.
>
>         My question is -  what exactly is the currently level of
>         LEF/DEF support in the tool?  I want to create a library
>         including the basic cells (this works); then create a
>         schematic facet and import the DEF to provide the instantiation
>         and connectivity info (this did not work for me). Finally,
>         I want to use the router to connect-up the ports (DEF has all
>         required placement and connectivity data).
>
>         As this did not work as I expected, what am I missing?
>         Any guidance or feedback is appreciated.
>
>         Thanks,
>         ---Andrew
>
> ps.  Also, am I correct in assuming that the OBS keyword in LEF
>      and non-DEFAULT via rules are NOT currently supported?

Unfortunately, the LEF/DEF implementation in Electric does not conform to 
any standard.  Some keywords are definitely missing.  It has been used to 
import from a few other systems, but is not guaranteed to work for all 
LEF/DEF.  It can work in two ways: (1) read LEF and then DEF or (2) read 
GDS and then LEF.  In either case, the LEF defines the connection sites and 
the DEF/GDS defines geometry.  Another unfortunate aspect of this process 
is that the geometry is not node-extracted, and thus is not in Electric's 
native representation.  Instead, the cells have "pure-layer nodes" and no 
topology.  They can be used in design, but only if you don't look too 
closely at their contents.

   -Steven Rubin