[libre-riscv-dev] Cell libraries needed for coriolis

Staf Verhaegen staf at fibraservi.eu
Fri Feb 7 17:12:08 GMT 2020

Luke Kenneth Casson Leighton schreef op vr 07-02-2020 om 15:43 [+0000]:
> On Fri, Feb 7, 2020 at 3:40 PM Jean-Paul Chaput<Jean-Paul.Chaput at lip6.fr> wrote:
> > 
> > Hello Luke,
> > There is also the mandatory point of the target technology. I got theimpressions that you wanted to use a 180nm one (which is the limit forwhich Coriolis can be made to work in a reasonable amount of time).
> yes, although i *think* staf might have access to 130nm.

In the NLNet project the tape-outs are foreseen to be on 180nm. I would like to stick to that for the moment.
I would see 130nm as a possible follow-up. These tape-outs will be sponsored by Google though, so I don't know if that is acceptable for libre-soc development.

> > This should be discussed with Staf also. This is important becausewe need that information to configure the symbolic layout for it(typically, how many metal layers, are they all usable for routingnormal wires and so on). Then we can make place & route that aresufficiently realistics.
> ok.

The process has 6 layers of metal. Metal2-Metal5 have the same min.space/min.width design rule. Metal6 is a thick metal so needs higher pitch. Via5 (between Metal5 and Metal6) also has bigger width and space so Metal5 will likely need to be higher pitch.
I think it is best to discuss the exact configuration first further off-line; exact dimensions of the technology are under NDA.

> > And lastly, there is the tricky part of writing the translation rulessymbolic to real (that is GDSII). We have tried to automate that inthe past but never finished for various non-technical reasons...This may be the occasion.
> that would be helpful, or at least know what needs to be done so itcan go on the list of tasks.

I will take care of S2R. DRC etc; of course if there is a bug in S2R I will need support.
I am doing standard cell development and S2R may not even be needed... In the mean time the nsxlib can be used for development of the place-and-route process.


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