[ibis-macro] Re: Draft Format and Usage Out Clarifications BIRD
- From: Mike LaBonte <mlabonte@xxxxxxxxxx>
- To: "IBIS-ATM" <ibis-macro@xxxxxxxxxxxxx>
- Date: Tue, 1 Nov 2016 17:23:27 -0400 (EDT)
The only allowable data Format for many Reserved_Paramneters including the
PAM4 Lower/Center/Upper ones is Value, and Default is illegal for Format
Value. So technically there should have been no Default to use, but there
should have been some kind of Value in the AMI file that a tool could use
when the model does not output it.. However, since IBIS says “For Usage Out,
the value in the AMI parameter leaves are determined by the Algorithmic
Model.” (oops, grammatical error), I don’t think tools should be silent
about substituting anything. Some people put unusable Values like “NA”,
attempting to cause a flag to be thrown on the play if it isn’t replaced.
Mike
From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Bob Miller ;(Redacted
sender "bob.miller" for DMARC)
Sent: Tuesday, November 01, 2016 5:05 PM
To: Curtis Clark
Cc: dmarc-noreply@xxxxxxxxxxxxx; Walter Katz; Mirmak, Michael; IBIS-ATM
Subject: [ibis-macro] Re: Draft Format and Usage Out Clarifications BIRD
The model maker can specify Usage InOut if that's the behavior they want,
right?
Yes. That's what I did to patch the model. In my particular case it wasn't
the value passed in that the model wanted or cared about; it merely used the
presence of the parameter in the parameters_in string to decide whether to
present the parameter at all in the parameters_out string. So in strict
terms the usage is not really InOut. This patch had the side-effect of
allowing the user to select a value for the parameter, which was summarily
ignored by the model.
Interesting enough (and possibly an issue), the EDA tool used the Default
value for this Reserved Parameter (PAM4_UpperEyeOffset) when the model
failed to return a value. No warning, no error, just mystically incorrect
post-simulation analysis.
I later modified the model to remove this "auto-hide" feature, rendering the
conundrum moot.
Question: What should the EDA tool do (if anything) when a Usage Out
parameter defined in the .ami file is NOT returned by the model?
Regards,
Bob
On Tue, Nov 1, 2016 at 2:26 PM, Curtis Clark <curtis.clark@xxxxxxxxx> wrote:
Walter is correct, here's the appropriate section (page 202 of IBIS 6.1):
The EDA tool shall pass a string to the executable model through the
AMI_parameters_in argument. This string shall contain all of the
leaf-formatted Usage In and Usage InOut AMI parameters if there are any
defined in the .ami file. No other information may be included in this
string. The string shall always include the root name of the parameter tree,
even if there are no parameters to pass to the algorithmic model.
Even without that explicit statement, I would consider it an error for the
EDA tool to put Usage out parameters in the AMI_parameters_in string. The
model maker can specify Usage InOut if that's the behavior they want, right?
Thanks,
Curtis
On Tue, Nov 1, 2016 at 2:16 PM, Bob Miller <dmarc-noreply@xxxxxxxxxxxxx>
wrote:
I agree with Walter. Been caught by this before (executable model subtly
expecting the EDA tool to pass Usage Out parameters into AMI_Init in the
parameter string). Some do, but more importantly, some don't as there is no
requirement to do so. I fixed my model rather than demand that all EDA tools
bow to me.
Regards,
Bob
On Tue, Nov 1, 2016 at 11:46 AM, Walter Katz <wkatz@xxxxxxxxxx> wrote:
MM,
The following implies that Usage Out arguments are passed by the EDA tool to
the executable model file in the **AMI_Parameters_In string to AMI_Init. I
do not think that this is correct.
Unless otherwise noted, specific Usage Out arguments or data provided as
Format are effectively ignored and will be simply passed by the EDA tool to
the executable model file.
Walter
From: ibis-macro-bounce@xxxxxxxxxxxxx
[
mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Mirmak, Michael
Sent: Tuesday, November 1, 2016 1:37 PM
To: IBIS-ATM (ibis-macro@xxxxxxxxxxxxx) <ibis-macro@xxxxxxxxxxxxx>
Subject: [ibis-macro] Draft Format and Usage Out Clarifications BIRD
As requested in a previous ATM meeting, please find enclosed a draft BIRD,
Format and Usage Out Clarifications.
Comments and questions are of course welcome and encouraged.
- MM
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