RE: [IBIS] RE: BIRD162: Change to Usage "Info, Out" for AMI Jitter and Noise Parameters

From: Muranyi, Arpad <Arpad_Muranyi@mentor.com>
Date: Thu Jul 11 2013 - 12:06:11 PDT
Bob,

Regarding Fangyi's suggestion, this is not something I
should decide (or agree/disagree).  We need to discuss
and decide his suggestion collectively.

I can see reasons for it being useful, but then the
question is why only Rx and why only the last call?
Making use of the values returned by Tx GetWave could
be just as useful in some cases, or making use of all
returned values between GetWave calls might also be
useful in some cases.

Whatever we decide, the bottom line is that the rules
should be spelled out in the specification clearly and
unambiguously.  For example, in the suggestion below I
read this:

"EDA tools should still be allowed to use the Rx parameters  returned by
the last GetWave operation."

This means that we need to state that only value returned
by Rx can be used by the EDA tool in this way, and only
its output from the last call within a simulation.  We may
also need to say a few words on what and how the EDA tool
can use these values for as opposed to the rest of the
returned values.  How would all this effect repeaters, and
back channel simulations?  Could the returned values from
one simulation be used in the next (in training), or could
the value of one channel be applied to the next channel
(in the case of repeaters), etc...

I don't think that a small tweak on that sentence can do
all this, we may need a few more sentences to achieve this.
An as you know, the more we write, the more discussion will
follow to get it right and unambiguous...  Do we have time
for that now?

Thanks,

Arpad
============================================================



From: Bob Ross [mailto:bob@teraspeed.com]
Sent: Thursday, July 11, 2013 10:30 AM
To: Muranyi, Arpad; ibis@eda.org
Subject: RE: [IBIS] RE: BIRD162: Change to Usage "Info, Out" for AMI Jitter and Noise Parameters

Arpad:

Your write-up looks good to me.

Regarding the second sentence, (first sentence in the second paragraph),
Fangyi suggested privately that it should apply only to Tx Jitter parameters:

If Tx jitter parameters are Usage Out, then the EDA Tool/Simulator shall use values returned by AMI_Init.


He stated that EDA tools should still be allowed to use the Rx parameters  returned by
the last GetWave operation.

Do you agree with this view, and should we modify the second paragraph
to capture these rules?

Bob


From: owner-ibis@eda.org<mailto:owner-ibis@eda.org> [mailto:owner-ibis@eda.org] On Behalf Of Muranyi, Arpad
Sent: Wednesday, July 10, 2013 10:48 PM
To: ibis@eda.org<mailto:ibis@eda.org>
Subject: RE: [IBIS] RE: BIRD162: Change to Usage "Info, Out" for AMI Jitter and Noise Parameters

How about something along these lines:


Note:

If the Jitter and Noise parameters are Usage Info, the EDA tool/simulator shall obtain their values

from the AMI parameter (.ami) file, optionally through a user interface if user selections are

available or needed.


If these parameters are Usage Out, the EDA tool/simulator shall use the values returned by the
AMI_Init function.  It is the model maker 's responsibility to make sure that the AMI_Init function
returns the appropriate value in these parameters to the EDA tool/simulator to achieve successful
simulations.

The model's AMI_GetWave function may also return values in these parameters to the EDA
tool/simulator, and these values are not required to be the same as the values previously
returned by the AMI_Init function.  The EDA tool/simulator may report the values returned
by the AMI_GetWave function to the user, but these values may not be used by the EDA
tool/simulator to modify or calculate parameter values passed into simulation models in
subsequent function calls or simulations, or to modify or calculate the simulation results
in any way.


Thanks,

Arpad
===================================

From: Bob Ross [mailto:bob@teraspeed.com]
Sent: Wednesday, July 10, 2013 7:13 PM
To: Muranyi, Arpad; ibis@eda.org<mailto:ibis@eda.org>
Cc: bob@teraspeed.com<mailto:bob@teraspeed.com>
Subject: RE: [IBIS] RE: BIRD162: Change to Usage "Info, Out" for AMI Jitter and Noise Parameters

Arpad:

I understand the concern.

An alternative paragraph might state:


Note:

The EDA Tool/Simulator shall use the values of the Jitter and Noise parameters directly (or as selected by the user according to the parameter Type descriptions) if they are Usage Info. If they are Usage Out, then the EDA Tool/Simulator shall use the values returned by AMI_Init. The model's AMI_GetWave function may return different values for these parameters than the values returned by AMI_Init; the EDA Tool/Simulator may report the values of such parameters to the user, but the EDA Tool/Simulator may not change any input to AMI models or change any result of the simulation based on the values returned for the Jitter and Noise parameters by AMI_GetWave.


Can you suggest improvements?

Bob


Bob

From: owner-ibis@eda.org<mailto:owner-ibis@eda.org> [mailto:owner-ibis@eda.org] On Behalf Of Muranyi, Arpad
Sent: Wednesday, July 10, 2013 4:17 PM
To: ibis@eda.org<mailto:ibis@eda.org>
Subject: RE: [IBIS] RE: BIRD162: Change to Usage "Info, Out" for AMI Jitter and Noise Parameters

Bob,

Good catch about referencing the BIRD at the end.  The
last sentence does not sound all that much better this
way either.

But in addition, I just realized that this entire note
only talks about what the EDA tool should do.  It doesn't
say what the responsibilities of the model maker is.  I
think we need to spell out that if any of these parameters
is Usage Out, the model maker has to make sure that the Init
function returns a valid value for the EDA tool, and then
we can mention that they can also return other values in
GetWave, but those will not be used by the EDA tool or
the model in any way to have an effect on the simulation,
or its results.

I am getting nitpicky now, but I also wonder about the word
"directly" in the first sentence.  I understand the intent,
meaning "from the .ami file not from the AMI model", but to
some the word "directly" might mean "without user intervention"
in the context of the EDA tool providing a GUI for the user to
select a specific value.  This can't be the case, since some
types might require user selection (list, range, etc...), but
the word "directly" might imply that...

Thanks,

Arpad
==============================================================

From: Bob Ross [mailto:bob@teraspeed.com]
Sent: Wednesday, July 10, 2013 5:36 PM
To: Muranyi, Arpad; ibis@eda.org<mailto:ibis@eda.org>
Cc: bob@teraspeed.com<mailto:bob@teraspeed.com>
Subject: RE: [IBIS] RE: BIRD162: Change to Usage "Info, Out" for AMI Jitter and Noise Parameters

Arpad:

Thanks for catching this.  The paragraph also contains a self-reference
to a BIRD.

I would reword the last clause from


Note:

The EDA Tool/Simulator shall use the values of these Jitter and Noise parameters directly if they are Usage Info. If they are Usage Out, then the EDA Tool/Simulator shall use their values generated by AMI_Init. The model's AMI_GetWave function may return different values for these parameters than the values returned by AMI_Init; the EDA Tool/Simulator may report the values of such parameters to the user, but the EDA Tool/Simulator may not change any inputs to AMI models or change other result of the simulation based on the values returned for the parameters in this BIRD by AMI_GetWave.


To


Note:

The EDA Tool/Simulator shall use the values of the Jitter and Noise parameters directly if they are Usage Info. If they are Usage Out, then the EDA Tool/Simulator shall use their values generated by AMI_Init. The model's AMI_GetWave function may return different values for these parameters than the values returned by AMI_Init; the EDA Tool/Simulator may report the values of such parameters to the user, but the EDA Tool/Simulator may not change any input to AMI models or change any result of the simulation based on the values returned for the Jitter and Noise parameters by AMI_GetWave.




Is this ok?

Bob


From: owner-ibis@eda.org<mailto:owner-ibis@eda.org> [mailto:owner-ibis@eda.org] On Behalf Of Muranyi, Arpad
Sent: Wednesday, July 10, 2013 11:52 AM
To: ibis@eda.org<mailto:ibis@eda.org>
Subject: [IBIS] RE: BIRD162: Change to Usage "Info, Out" for AMI Jitter and Noise Parameters

Thanks to the authors of this BIRD for the quick actions.
I would like to request that the following sentence be
corrected, because it is grammatically incorrect, and
because of that not clear (red emphasis added to point
to the problem area):

"...but the EDA Tool/Simulator may not change any inputs to AMI models or change other result of the simulation based on the values returned..."

Thanks,

Arpad
==========================================================

From: owner-ibis@eda.org<mailto:owner-ibis@eda.org> [mailto:owner-ibis@eda.org] On Behalf Of Mirmak, Michael
Sent: Tuesday, July 09, 2013 9:23 PM
To: ibis@eda.org<mailto:ibis@eda.org>
Subject: [IBIS] BIRD162: Change to Usage "Info, Out" for AMI Jitter and Noise Parameters

BIRD162, Change to Usage "Info, Out" for AMI Jitter and Noise Parameters, has been posted on behalf of Bob Ross of Teraspeed Consulting Group, Walter Katz of Signal Integrity Software (SiSoft), and Fangyi Rao of Agilent Technologies.



The text may be found at http://www.eda.org/ibis/birds/bird162.docx (the text is not attached here due to a reflector policy prohibition on attachments). The BIRD will be introduced at the next IBIS Open Forum teleconference.



A complete list of BIRDs, including the status of each, is available at: http://www.eda.org/ibis/birds/



      Michael Mirmak

      Intel Corp.

      Chair, IBIS Open Forum


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