Arpad,
The original intent was to allow users to:
1. Define repeater records in an IBIS file so that an Rx could be paired
with a Tx to form a repeater
2. Define two kinds of repeaters, a Retimer and a Redriver
3. Define the sequence of Init flows and GetWave flows for both Redrivers
and Retimers
4. Self-Optimization was always considered for both the Tx2 and Rx2. If
not,
why is the input to the Tx2 the IR of the downstream channel? The answer was
so the Tx2 could optimize itself. For Retimers, the input to the Rx2 was
just the output of the Tx2. For the Redriver, it was an oversite to not
include the output of Rx1 in either the input to the Tx2 or the input to the
Rx2.
No flow is valid unless it incorporates the ability of an Rx to optimize
itself. AMI specifically supports this because the AMI_Init can return the
values of AMI parameters such at tap coefficients. There are examples of
this in the specification (e.g. mySampleAMI on page 210.
Walter
Walter Katz
wkatz@xxxxxxxxxx <mailto:wkatz@xxxxxxxxxx>
Phone 303.449-2308
Mobile 303.335-6156
From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Monday, June 19, 2017 5:13 PM
To: ibis-macro@xxxxxxxxxxxxx
Subject: [ibis-macro] Re: Response to BIRD-190
Walter,
In this case, whether the redriver reference flow is correct or wrong seems
to depend on what you want to do in the simulation. What I am hearing in
this conversation is that the flow is only wrong if the Init function
contains
optimization. But if the original intent of the spec did not include such
optimizations, then the flow seems to be OK.
So what was the original intent?
Thanks,
Arpad
===========================================================
From: Walter Katz [mailto:wkatz@xxxxxxxxxx]
Sent: Monday, June 19, 2017 4:04 PM
To: Muranyi, Arpad <Arpad_Muranyi@xxxxxxxxxx
<mailto:Arpad_Muranyi@xxxxxxxxxx> >; ibis-macro@xxxxxxxxxxxxx
<mailto:ibis-macro@xxxxxxxxxxxxx>
Subject: RE: [ibis-macro] Re: Response to BIRD-190
Arpad,
Yes, there are reference flows, and the Redriver reference flow is wrong. It
has an error in it. The error should be corrected because it gives the wrong
result. I announced that this error existed as soon as I found it. The error
is there whether Rx2 has a DFE or not. Even if the Rx2 was LTI in your
definition of LTI (e.g. it has a CTLE that can be changed as a function of
the IR of the upstream channel).
If the standard gives the wrong answer and if IBIS is unable to correct it,
then all we can do is document that IBIS 6.1 flow is incorrect, and that
SiSoft follows a flow that is correct.
Walter
Walter Katz
wkatz@xxxxxxxxxx <mailto:wkatz@xxxxxxxxxx>
Phone 303.449-2308
Mobile 303.335-6156
From: ibis-macro-bounce@xxxxxxxxxxxxx
<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Monday, June 19, 2017 4:30 PM
To: ibis-macro@xxxxxxxxxxxxx <mailto:ibis-macro@xxxxxxxxxxxxx>
Subject: [ibis-macro] Re: Response to BIRD-190
Walter,
What happened to the promise of interoperability and portability?
Also, pg. 177 states the following:
So while the flows are not a requirement, the purpose of them is to
establish something that can be followed to arrive to the same results…
If all EDA vendors can do anything they want, and generate different
results because they feel it is the correct answer, we might as well
kiss the spec good bye…
Thanks,
Arpad
========================================================
From: Walter Katz [mailto:wkatz@xxxxxxxxxx]
Sent: Monday, June 19, 2017 3:21 PM
To: Bob Miller (APD) <bob.miller@xxxxxxxxxxxx
<mailto:bob.miller@xxxxxxxxxxxx> >; Ambrish Varma <ambrishv@xxxxxxxxxxx
<mailto:ambrishv@xxxxxxxxxxx> >
Cc: Muranyi, Arpad <Arpad_Muranyi@xxxxxxxxxx
<mailto:Arpad_Muranyi@xxxxxxxxxx> >; ibis-macro@xxxxxxxxxxxxx
<mailto:ibis-macro@xxxxxxxxxxxxx>
Subject: RE: [ibis-macro] Re: Response to BIRD-190
All,
Ultimately, AMI is a specification of the format and syntax of a .ami file
and what the inputs and outputs are of a DLL. It is important that the model
makers write DLLs in accordance with the standards defines of their inputs
and outputs.
It is not a requirement of an EDA tool follow the flows suggested in the
standard. SiSoft and other companies believe the flow in IBIS 6.1 gives the
wrong answer, as we stated three years ago. SiSoft uses a flow that gives
the correct answer, and submitted BIRD 166 to document this.
If other EDA companies state that they are getting the correct answer
because they religiously execute the flows documented in IBIS 6.1, so be it.
Bottom line is when a customer gets a different results from different EDA
vendors we can point them to this discussion and they can decide who is
right, since we cannot.
Walter
Walter Katz
wkatz@xxxxxxxxxx <mailto:wkatz@xxxxxxxxxx>
Phone 303.449-2308
Mobile 303.335-6156