Subject: Re: Minutes, IBIS Teleconference Meeting 7/20
From: Lynne Green (lgreen@cadence.com)
Date: Wed Jul 25 2001 - 09:07:10 PDT
The EDA tools have to be able to use these models, which means the models
must pass the parser.
A smart user will send the model back to the person who made it, to verify
whether the non-monotonicity is "real", before proceeding with simulation.
- Lynne
At 09:13 AM 7/25/2001 +0800, LiuWeidong wrote:
>For the message bellow,
>" Even though the model is non-monotonic, it may represent real data"
>" (3) ignore this problem and force the user to modify the IBIS file."
>" Bob suggested that we work on (1) as a low priority activity. If the
>fix is too difficult, then we might consider (3). No one wanted (2). "
>
>I want to ask:
>It seems that a good model maybe is non-monotonic(right or wrong ?),Then
>how can we modefy the IBIS file ?
>
>Thanks,
>regards,
>LiuWeidong
>
>----- Original Message ----- >
> >
> > IBISCHK3 BUG TRACKING
> > - BUG57 Non-Mononic Table Causes Waveform Endpoint Test to Fail
> > Bob Ross introduced BUG57 by pointing out that if the [Pulldown] and/or
> > the [Pullup] table contains non-monotonic data in the clamping regions,
> > and
> > there are no [Gnd Clamp] or [Power Clamp] tables, ibischk3 gives an
> > incorrect Error message.
> >
> > The non-monotonic data itself causes ibischk3 to calculate the wrong
> > endpoint values because the algorithm probably has numerical
> difficulties.
> > It probably starts its convergence calculation at one end of the table
> > rather than from the middle and gets numerically confused with the
> > non-monotonic data.
> >
> > Even though the model is non-monotonic, it may represent real data. Some
> > EDA tools will correctly process the model. However, the recently
> > implemented Waveform endpoint tests now report an Error instead of a
> > Warning, preventing the model to be processed in systems that uses
> > ibischk3
> > for input model parsing.
> >
> > Bob suggested classifying BUG57 as Annoying, Low, and Open.
> >
> > The problem is how to resolve BUG57. The choices are (1) fix the test,
> > (2)
> > change the Error back to a Warning, or (3) ignore this problem and force
> > the
> > user to modify the IBIS file.
> >
> > Bob suggested that we work on (1) as a low priority activity. If the fix
> > is
> > too difficult, then we might consider (3). No one wanted (2). Stephen
> > Peters suggested that a note could be added to the Warning or Error
> > message
> > to alert the user of a possible reason for the Error Message so that the
> > user could modify the model. Bob suggested that because this is a low
> > priority bug, it should be investigated after all the other open bugs are
> > fixed. Then we can decide how to proceed.
> >
> >
This archive was generated by hypermail 2b28 : Wed Jul 25 2001 - 09:09:17 PDT