Re: [IBIS-Users] RE: model type IO_OpenPullUp and "output logic threshold" requirement

John:

I believe the message means that Input thresholds
Vinh and Vinl are needed (as a psuedo requirement
for all Input and I/O_* Model_types).

For historical backward compatibility reasons this
was not made a requirement in the Spec. - (with an Error
message), but for all EDA tools, it is a psuedo requirement.

In your case, the Model_type in the IBIS model is
I/O_open_drain. So the Cadence warning is consistent
with the official IBIS parser.

Bob

Lipsius, JohnX S wrote:

>
>
> Follow up...
>
>
>
> The IBIS 3.2 spec has no mention of the Model statement needing an
> "output logic threshold".
>
> Looks like a Cadence problem?
>
>
>
>
>
>
>
> ------------------------------------------------------------------------
>
> From: Lipsius, JohnX S
> Sent: Thursday, June 24, 2004 8:15 PM
> To: 'ibis-users@eda.org'
> Subject: model type IO_OpenPullUp and "output logic threshold" requirement
>
>
>
>
>
> All,
>
>
>
> I got this warning:
>
>
>
> "IOCell <LKPT_UP_0P25_1066_strong> is type IO_OpenPullUp and so:
> should contain an output logic threshold"
>
>
>
> Any ideas as to resolution?
>
>
>
>
>
> It is purely a warning from the "DML check" performed by the Cadence
> IBIS simulator's parser. I've started an inquiry into this one because
> I can't find reference to this issue in IBIS specifications regarding
> this model type requiring logic threshold data.
>
>
>
> I have these lines in the IBIS file:
>
>
>
> [Model] weak
>
> Model_type I/O_open_drain
>
>
>
> ...and the same for strong and typical.
>
>
>
>
>
> Thanks,
>
> John
>
>
>
>
>
>
>

-- 
Bob Ross
Teraspeed Consulting Group LLC     Teraspeed Labs
121 North River Drive              13610 SW Harness Lane
Narragansett, RI 02882             Beaverton, OR 97008
503-750-6481                       503-430-1065
http://www.teraspeed.com           503-246-8048 Direct
bob@teraspeed.com
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