[ibis-editorial] Re: What is the relationship between "clock_times" and "Ignore_Bits"?
- From: "Fangyi Rao" <dmarc-noreply-outsider@xxxxxxxxxxxxx> ("fangyi_rao")
- To: Ambrish Varma <ambrishv@xxxxxxxxxxx>, IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>, "ibis-editorial@xxxxxxxxxxxxx" <ibis-editorial@xxxxxxxxxxxxx>
- Date: Tue, 13 Sep 2022 18:58:34 +0000
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 <ibis-macro-bounce@xxxxxxxxxxxxx> On
Behalf Of Ambrish Varma
Sent: Tuesday, September 13, 2022 11:55 AM
To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>; 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.
My question is not so much ***when***, but ***how much oof it***. In other
words, is the EDA
tool expected to remove (delete) the beginning of the clock_times vector
generated by the DQS Rx
AMI model by the amount of entries that corresponds to Ignore_Bits before it
passes that vector
into the DQ Rx AMI model?
Thanks,
Arpad
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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 Ambrish Varma
Sent: Tuesday, September 13, 2022 1:16 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"?
Hi Arpad,
My understanding is that ignore_bits tells the tool when to start collecting
data for eye statistics/post processing.
If the DQS .ami file says Ignore_Bits=100, it means that the DQS model is
telling the tool ‘to accumulate
waveform statistics after the EDA tool has completed simulation of a number of
UI equal to
Ignore_Bits’ – i.e 100 UIs.
It should have no implication on when the clock_times vector gets passed 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 1:55 PM
To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx<
mailto:ibis-macro@xxxxxxxxxxxxx>>;
ibis-editorial@xxxxxxxxxxxxx<
mailto:ibis-editorial@xxxxxxxxxxxxx>
Subject: [ibis-macro] What is the relationship between "clock_times" and
"Ignore_Bits"?
EXTERNAL MAIL
Hello Everyone,
I ran into another question with “clock_times” in the context of
Rx_Use_Clock_Input.
How is “Ignore_Bits” come into this picture? I couldn’t find the answer in the
spec…
For example, is the EDA tool expected to suppress (delete) the clock time
values from
the beginning of the clock_times vector returned by a DQS Rx AMI model up to the
point that is defined by Ignore_Bits before passing it into the DQ Rx AMI model?
Let’s say the first clock time generated by the DQS Rx model is around the 5th
bit (UI),
but the DQS .ami file says Ignore_Bits = 100. Is the EDA tool supposed to
remove the
first 95 or so numbers from the clock_times vector and pass a clock_times
vector to the
DQ Rx AMI model that starts only after the 100th bit?
Thanks,
Arpad
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