Thanks Walter for reminding me to the fact that the waveform is coming out of
the DQS GetWave function. For some odd reason I forgot that (“brain fart”),
and thought that the waveform was also returned by the DQS Rx GetWave
function in the clock_times vector (just as it is placed into the clock_times
vector for the DQ Rx AMI model)…
Sorry for my confusion…
Thanks,
Arpad
===================================================================
From: Walter Katz <wkatz@xxxxxxxxxxxxx>
Sent: Friday, September 9, 2022 7:53 AM
To: Muranyi, Arpad <Arpad_Muranyi@xxxxxxxxxx>; IBIS-ATM
<ibis-macro@xxxxxxxxxxxxx>; ibis-editorial@xxxxxxxxxxxxx
Subject: RE: Another observation regarding “Wave” and “Times”
Arpad,
Comments below.
Walter
Walter Katz
Work 508.647-7633
Cell 720.417-3762
wkatz@xxxxxxxxxxxxx<mailto:wkatz@xxxxxxxxxxxxx>
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From:
ibis-editorial-bounce@xxxxxxxxxxxxx<mailto:ibis-editorial-bounce@xxxxxxxxxxxxx>
<ibis-editorial-bounce@xxxxxxxxxxxxx<mailto:ibis-editorial-bounce@xxxxxxxxxxxxx>>
On Behalf Of Muranyi, Arpad
Sent: Friday, September 9, 2022 12:23 AM
To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>>;
ibis-editorial@xxxxxxxxxxxxx<mailto:ibis-editorial@xxxxxxxxxxxxx>
Subject: [ibis-editorial] Another observation regarding “Wave” and “Times”
Hello Everyone,
I ran across another potential problem regarding “Wave” and “Times” that we
might
need to address in the IBIS spec.
First, consider that currently there is no way to tell a DQS Rx AMI model
whether it
should generate a waveform or clock times for the DQ Rx AMI model that relies on
its output data.
WMK> The DQS Rx AMI_GetWave model always returns Wave.
Next, consider that currently there is no rule in the spec about when “Wave” or
“Times”
may be used in the DQ Rx AMI model’s Rx_Use_Clock_Input parameter. This means
that
it is perfectly legal to write a DQ Rx AMI model that has *both* “Wave” *and*
“Times”
in the Rx_Use_Clock_Input AMI parameter. When both “Wave” and “Times” are
present,
the user can usually make a selection in the GUI of their EDA tool’s AMI
parameter
configuration dialog. But how would the DQS model find out what the user’s
selection
is so that it could generate the desired output for the DQ Rx model?
WMK> Rx_Use_Clock_Input is an “In”, therefore the DLL know if it is “None”,
“Times” or “Wave”.
The specification says:
Other Notes: The wave input to both Data and Clock shall have the same block
size and sample_interval. For the “Wave” option, if the Clock does not have a
DLL or has a DLL without an AMI_GetWave, then the EDA tool should effectively
insert a passthrough Clock AMI_GetWave function to make the clock waveform
available for the Data AMI_GetWave clock_times input. For the “Times” option,
the Clock shall have a DLL with an AMI_GetWave that returns clock_times.
Therefor, if “Times” is an option the DQS Rx “shall have a DLL with an
AMI_GetWave that returns clock_times.”
Alternately, we would need to have a way to select one of two DQS Rx AMI models
(one of which would generate “Wave” and the other would generate “Times”) based
on the user’s selection.
I didn’t think too much about whether this could be solved with more complicated
keywords, such as “Dep” and the like, but I suspect that we have a problem here.
Another possible solution (probably the easiest and quickest) would be to
prohibit
“Wave” and “Times” to be used *together* for the same DQ Rx AMI model in its
Rx_Use_Clock_Input parameter.
Thoughts?
Thanks,
Arpad
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