[ibis-macro] Re: usage type of Tx_DCD and Tx_Jitter in IBIS 6.0
- From: Mike Steinberger <msteinb@xxxxxxxxxx>
- To: ibis-macro@xxxxxxxxxxxxx
- Date: Wed, 03 Jul 2013 20:52:15 -0500
Fang-yi-
Thanks for raising this question. As it happens, about a month ago, I
had to tell a customer that a problem couldn't be solved in a way that
was compliant with IBIS because of exactly the issue you're raising.
When a specification explicitly excludes solutions to real problems, I
consider that to be a bad thing.
Thanks again.
Mike S.
On 07/03/2013 08:44 PM, Walter Katz wrote:
Fangyi,
When BIRD 123 was discussed, we had a specific discussion on whether
the new parameters should be Info or Info/Out, I left that decision to
the ATM committee. The ATM committee agreed__that they should be only
Info, and for consistency Tx_DCD and Tx_Jitter should not be out. I
think some of the EDA vendors did not want the simulator to change
behavior as the results of outputs of the Model, but I think you
should go back to the minutes for more specific reasons. The version
BIRD_123.3_Draft2.docx (11/1/2011) had all of the new parameters as
Info or Out, BIRD_123 3_Draft3.docx (12/14/2011) had them just Info.
Also in BIRD_123.3_Draft2.docx (11/1/2011) there was the following
that got removed when we chose to make these parameters just Info:
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.
SiSoft could have gone either way, but deferred to the other EDA
vendors who felt that they did not want to support these parameters
changing on the fly.
So you can look at the minutes between November 1 and December 14 to
find out who said what and why the decision was made this way.
Walter
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*Sent:* Wednesday, July 03, 2013 7:56 PM
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*Subject:* [ibis-macro] usage type of Tx_DCD and Tx_Jitter in IBIS 6.0
It seems that in IBIS 6.0 Tx_DCD and Tx_Jitter are no longer allowed
to have usage type Out. Can anyone remind me why?
Thanks,
Fangyi
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