Thank you all for your answers. I am glad to hear that we are in complete
agreement on this. (I also agree with what every one of you are saying, I
just had to raise the question because I ran into a model recently that was
“misbehaving” if I didn’t remove a few time values from the beginning of
the clock_times vector it generated).
Maybe this unanimous agreement will help us to get away with just a simple
clarification BIRD (or just a simple Editorial change) for IBIS v7.2.
Thanks,
Arpad
===============================================================
From: ibis-macro-bounce@xxxxxxxxxxxxx <ibis-macro-bounce@xxxxxxxxxxxxx> On
Behalf Of Walter Katz
Sent: Tuesday, September 13, 2022 2:44 PM
To: fangyi_rao@xxxxxxxxxxxx; Ambrish Varma <ambrishv@xxxxxxxxxxx>; IBIS-ATM
<ibis-macro@xxxxxxxxxxxxx>; ibis-editorial@xxxxxxxxxxxxx
Subject: [ibis-macro] Re: What is the relationship between "clock_times" and
"Ignore_Bits"?
Arpad,
I agree with both Ambrish and Fangyi. Ignore bits is the time it takes for all
of the equalization to settle. The clock times that are before ignore bits are
critical to the channel equalizing, so they absolutely cannot be ignored.
Walter
Walter Katz
Work 508.647-7633
Cell 720.417-3762
wkatz@xxxxxxxxxxxxx<mailto:wkatz@xxxxxxxxxxxxx>
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From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>
<ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>> On
Behalf Of Fangyi Rao
Sent: Tuesday, September 13, 2022 2:59 PM
To: Ambrish Varma <ambrishv@xxxxxxxxxxx<mailto:ambrishv@xxxxxxxxxxx>>; IBIS-ATM
<ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>>;
ibis-editorial@xxxxxxxxxxxxx<mailto:ibis-editorial@xxxxxxxxxxxxx>
Subject: [ibis-macro] Re: What is the relationship between "clock_times" and
"Ignore_Bits"?
Hi Arpad,
I agree with Ambrish. Please note that symbol_time is just a nominal value and
the actual UI in both DQ and DQS signals can be different from symbol_time and
time-varying due to jitter and other factors. The EDA tool should not modify
the clock_times content. The tool should just pass the raw clock_times data
returned by DQS Rx GetWave directly into the DQ Rx GetWave.
On the other hand, in cases of Rx_Use_Clock_Input=”Wave” there is no ambiguity
about the content of clock_times passed into DQ Rx.
Best,
Fangyi
From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>
<ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>> On
Behalf Of Ambrish Varma
Sent: Tuesday, September 13, 2022 11:55 AM
To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>>;
ibis-editorial@xxxxxxxxxxxxx<mailto:ibis-editorial@xxxxxxxxxxxxx>
Subject: [ibis-macro] Re: What is the relationship between "clock_times" and
"Ignore_Bits"?
CAUTION: This message originates from an external sender.
Hi Arpad,
Passing of the data between DQS and DQ model does not constitute collecting
data for eye statistics/post processing – hence Ignore_Bits should not be a
factor at all.
This is analogous to collecting clock_times vector from a normal SERDES AMI
model. The tool starts collecting that from when the model starts sending it.
It does not wait for Ignore_Bits to end before it starts collecting that data.
So – to answer your question directly – the EDA tool is not expected to
remove/delete anything before it passes the vector to the DQ Rx AMI model.
Thanks,
Ambrish.
From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>
<ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>> On
Behalf Of Muranyi, Arpad
Sent: Tuesday, September 13, 2022 2:27 PM
To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>>;
ibis-editorial@xxxxxxxxxxxxx<mailto:ibis-editorial@xxxxxxxxxxxxx>
Subject: [ibis-macro] Re: What is the relationship between "clock_times" and
"Ignore_Bits"?
EXTERNAL MAIL
Ambrish,
Thanks for your reply. I tend to agree with your answer, but I need to clarify
your last sentence:
It should have no implication on when the clock_times vector gets passed
to the DQ Rx AMI model.