[ibis-macro] Re: FW: [IBIS] BIRD119: IBIS-AMI New Reserved Parameters > initial feedback
- From: <fangyi_rao@xxxxxxxxxxx>
- To: <twesterh@xxxxxxxxxx>, <ibis-macro@xxxxxxxxxxxxx>
- Date: Tue, 12 Oct 2010 13:01:45 -0600
I have some additional questions regarding this BIRD.
Supporting_Files: Usage Info, how EDA tools use this parameter?
Broadband Analog Model Parameters:
1. What are the big triangles in figures on p.7?
2. What is the waveform of the voltage source in line 11 on p.7?
3. How do Voh and Vol work with voltage range, pull-up/pull down and V-T
tables in regular ibis model?
4. What are the definitions of Voh_H, Vol_H, Voh_L and Vol_L? What are
their waveforms?
5. Why are signals of ports 2 and 4 summed in "Default Rx Node map" plot
on p.7?
Equivalent-Circuit Analog Model parameters:
1. What are the big triangles in figures on p.9?
2. How do Voh, Vol, Vt, Tr and Tf work with voltage range, pull-up/pull
down and V-T tables in regular ibis model?
3. What are the definitions of Voh_H, Vol_H, Voh_L, Vol_L and Vt? What
are their waveforms?
4. Why are signals of Rx output summed in "Rx Analog Buffer Equivalent
Circuit" plot on p.9?
Parameters in Broadband Analog Model and Equivalent-Circuit Analog Model have
duplicated functionalities of regular ibis parameter. I think they should be
combined with regular ibis parameters instead of AMI parameters.
Jitter, Noise and Clock Parameters:
1. What are the definitions of Rx_Clock_Recovery_Rj, Rx_Clock_Recovery_Sj
and Rx_Clock_Recovery_DCD?
2. Why there is no Rx_Clock_Recovery_Sj_frequency
3. What are the definitions of Rx_Rj, Rx_Sj and Rx_DCD? How are they
different from Rx_Clock_Recovery_Rj, Rx_Clock_Recovery_Sj and
Rx_Clock_Recovery_DCD?
4. Why there is no Rx_Sj_frequency
Thanks,
Fangyi
From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx]
On Behalf Of Todd Westerhoff
Sent: Tuesday, October 12, 2010 7:05 AM
To: 'IBIS-ATM'
Subject: [ibis-macro] Re: FW: [IBIS] BIRD119: IBIS-AMI New Reserved Parameters
> initial feedback
Ken,
Thanks for your comments.
The BIRD was submitted to the IBIS Open Forum so that everyone would have a
convenient way to refer to the document. With multiple BIRDs being discussed
in the Tuesday meetings, we wanted to be sure that there was a simple and
unambiguous way to refer to this one. We always expected the bulk of the
technical discussions to occur in the Tuesday IBIS-ATM meetings.
Your other notes are good discussion points for the IBIS-ATM meetings. The
technical background behind some of these points is fairly involved, so it's
better suited for a real-time discussion than a yet another really long email
thread that no one has the time to read. ;-)
Talk to you this afternoon,
Todd.
________________________
Todd Westerhoff
VP, Software Products
SiSoft
6 Clock Tower Place, Suite 250
Maynard, MA 01754
(978) 461-0449 x24
twesterh@xxxxxxxxxx<mailto:twesterh@xxxxxxxxxx>
www.sisoft.com<http://www.sisoft.com>
________________________________
From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx]
On Behalf Of Ken Willis
Sent: Monday, October 11, 2010 11:44 AM
To: 'IBIS-ATM'
Subject: [ibis-macro] FW: [IBIS] BIRD119: IBIS-AMI New Reserved Parameters >
initial feedback
Hello all,
We have several issues with this BIRD. The first is the process. It is unclear
why this large BIRD would go straight to the IBIS Open Forum instead of first
pass through the IBIS-ATM committee. Many items in here have significant
implications that need to be considered. Is the intent to simply introduce it
at the Open Forum, but still review in IBIS-ATM?
Beyond that, there are some important technical items that raise concern:
- The section on "Data Management / Sim Control" has some good ideas in
it. We think this should be moved into its own BIRD, instead of lumped together
with all this other content.
- A fundamental disagreement is with the Broadband and Equivalent Circuit
Analog Model sections. From the beginning of the AMI effort several years back,
a very clear distinction was introduced between the "circuit" part of the
problem, which is involved in the initial impulse response characterization,
and the "algorithmic" part of the problem, which was on-chip content that
focused on the equalization. But here it appears the authors are pushing the
circuit modeling into AMI as well. We think that is the WRONG direction.
Traditional IBIS already has functionality to handle the circuit part of the
problem. External Model syntax today can fully handle the parameterized
subcircuit functionality proposed here with the "Equivalent Circuit Analog
Model", and is confusing and extraneous here. Adding support for S-parameters
is an excellent move, but BIRD 116 to add ISS to External Model completely
takes care of this. The AMI portion of IBIS should be exclusively focused on
the on-chip equalization modeling, and not redundantly re-define circuit
modeling of traditional IBIS/External Model.
- The remaining content focuses on jitter/noise. It makes sense to put
this into its own BIRD, and we support this discussion wholeheartedly. But
again we sense a fundamental issue here. The original AMI spec defined
"Reserved_Parameters" and "Model_Specific' parameters. The former was for the
EDA tool, and the latter is obviously for the specific model. But there are
several of the proposed new Reserved_Parameters that should be associated with
the specific model instead of generically to the EDA tool. A good example of
this is Sj-related items. This is directly tied to how the model developer
implements their CDR functionality in the algorithmic model, and not
universally to EDA tools. So this section looks promising, but needs
significant review before it should leave the IBIS-ATM committee and go to the
Open Forum.
We look forward to discussing these items Tuesday.
Thanks,
Ken Willis
Sigrity, Inc.
860-871-7070
kwillis@xxxxxxxxxxx<mailto:kwillis@xxxxxxxxxxx>
________________________________
From: owner-ibis@xxxxxxx [mailto:owner-ibis@xxxxxxx] On Behalf Of Mirmak,
Michael
Sent: Wednesday, October 06, 2010 11:54 AM
To: ibis@xxxxxxxxxxxxxx
Subject: [IBIS] BIRD119: IBIS-AMI New Reserved Parameters
The enclosed BIRD 119, IBIS-AMI New Reserved Parameters, is distributed on
behalf of Walter Katz, Mike Steinberger and Todd Westerhoff of SiSoft. It will
be introduced at the next IBIS Open Forum meeting.
A full list of BIRDs, their status and association with particular IBIS
versions may be found at http://www.eda.org/ibis/birds/.
Please note that the enclosed file is a "pointer" to a separate PDF file of the
BIRD text, as the IBIS e-mail reflector does not permit redistribution of
binary files. The enclosed file is identical to the ASCII file on the BIRD
list at the URL above. The complete BIRD text is available at:
http://www.eda.org/ibis/birds/bird119/bird119.pdf
Michael Mirmak
Intel Corp.
Chair, IBIS Open Forum
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