[ibis-macro] Re: AMI-init should pass modified IR to getwave....

  • From: "Todd Westerhoff" <twesterh@xxxxxxxxxx>
  • To: "'IBIS-ATM'" <ibis-macro@xxxxxxxxxxxxx>
  • Date: Thu, 14 Jun 2012 09:39:48 -0400 (EDT)



When you say "On chip RDL", are you specifically talking about the
interconnect between the die pad and the buffer itself?  Where is the
receiver termination physically taking place?




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Todd Westerhoff

VP, Software Products


Signal Integrity Software Inc. .  <http://www.sisoft.com/> www.sisoft.com

6 Clock Tower Place . Suite 250 . Maynard, MA 01754

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From: ibis-macro-bounce@xxxxxxxxxxxxx
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Taranjit Kukal
Sent: Thursday, June 14, 2012 2:04 AM
Subject: [ibis-macro] AMI-init should pass modified IR to getwave....


Hi All,

When I was implementing AMI model, I found a situation where it was
important that Rx ami_init needed to pass modified-IR to getwave function.

Reason was that Chip-RDL-routing was available as Impulse-Responses.

Removal for "Use_Init_Output" to make Statistical-flow independent of
Transient-flow,  is going to break the original intent where init and
getwave were supposed to work in conjunction with each other handling
linear and non-linear filtering portions respectively (as shown below)




I would go back to Arpad's suggestion (year 2010) for having two
Impulse-responses coming out of ami_init

-          One that goes to EDA tool for statistical flow

-          One that gets passed to getwave to allow splitting of
modeling-effort across init and getwave and make things easy for linear


BIRD120 was brought up that deprecates use of "use_init_output" with a
view to keep statistical and time-domain simulations independent. But as I
think more, we need to allow both capabilities. It absolutely does not
make sense to implement simple linear filters within getwave when we can
convolute the filter-IR with channel-IR. We should take all steps to make
modeling easy and ensure enough flexibility.


This way, we cover both the scenarios - those who want to leverage init as
complement to getwave and those who want to keep statistical-flow purely
independent. Since this does not bring any disadvantage, I strongly feel
that we all re-consider outputting two modified-IRs out of init function -
one for statistical-flow and another one to complement getwave filtering. 






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