Good point!
Mike
On 11/26/2018 11:31 AM, Ambrish Varma wrote:
All,
We have already received a few questions about the (Model_Specific (Tstonefile)) parameter in IBIS 6.1. To remove any ambiguity – we should also remove the ‘s4p’ extension from the file name.
Thanks,
Ambrish.
*From:*ibis-macro-bounce@xxxxxxxxxxxxx <ibis-macro-bounce@xxxxxxxxxxxxx> *On Behalf Of *Mike LaBonte
*Sent:* Monday, November 26, 2018 11:18 AM
*To:* ibis-macro@xxxxxxxxxxxxx
*Subject:* [ibis-macro] Re: Usage Dep example
EXTERNAL MAIL
If it has required this much discussion, then we probably need a well-considered BIRD, for a future spec. I do think that dropping "Rx analog model" for IBIS 7.0 would be a good idea. It leaves us with an example in which the purpose of "my_file" is not explained, but at least it doesn't mislead.
Mike
On 11/26/2018 12:48 AM, Muranyi, Arpad wrote:
Mike,
Like I said in my previous email, I initially suggested the same
as you, to use
Ts4file and move it up to the Reserved Parameter section, but
others in that
meeting felt that it would be too much of a change, and we could
just do what
we did, change it to my_file and thereby disassociate the example
from the
BIRD158 concepts. We just forgot to change the Description. I
think the easiest
and quickest way to fix this would be to change the Description
(and if we still
don’t like it we can file it away as a known issue and address it
for the next
revision). Do you think that would be still too confusing?
Thanks,
Arpad
==============================================================
*From:*Mike LaBonte [mailto:mlabonte@xxxxxxxxxx]
*Sent:* Saturday, November 24, 2018 7:08 PM
*To:* Muranyi, Arpad <Arpad_Muranyi@xxxxxxxxxx>
<mailto:Arpad_Muranyi@xxxxxxxxxx>; ibis-macro@xxxxxxxxxxxxx
<mailto:ibis-macro@xxxxxxxxxxxxx>
*Subject:* Re: [ibis-macro] Usage Dep example
Yes, we eliminated "TStonefile" because it was not an official
means to designate an on-die model, and we did not want to imply
that. But "my_file" is still described as the "Rx analog model",
and that is an impossible example because only a
Reserved_Parameter can do that. Maybe the issue here is that we
have not yet found a purpose for Usage Dep, other than to
calculate an analog model.
Stretching to find an example: maybe a Tx buffer that has presets
could have Dep tap coefficients that AMI_Resolve would report out,
based on the preset input. That would allow the EDA tool to know
the coefficients in advance, and pass them into AMI_Init. But even
that is not a great example, because the preset could simply be
passed to AMI_Init, which would report the calculated coefficients
as Out parameters. And Dep parameters are not passed to AMI_Init
anyway, so the EDA tool would never know to pass the coefficients
back in. This would not be a valid example.
Can anyone think of a Model_Specific Dep parameter that makes more
sense? If not, then since we do now have Ts4File, to me it makes
sense to use that as the example. What we have now is confusing.
An alternative would be to delete "Rx analog model. " from the
Description in that example, and simply leave it vague what
my_file is for.
Mike
On 11/24/2018 6:36 PM, Muranyi, Arpad wrote:
Mike,
If I remember correctly, “my_file” used to be “Tstonefile” in
this example, and
I raised the same questions as you did. Instead of changing
it to Ts4file and
moving it to the Reserved Parameters section, it was decided
to change it to
“my_file” because the purpose of the file could be all kinds
of things, other than
a BIRD158 style buffer model. We just forgot to change the
Description after
we did that. Even though I agree with you, I think since the
group decided to
handle the situation this way, we should just correct the
Description so that
it would not make people think that this is a BIRD158 style
buffer example.
Thanks,
Arpad
================================================================
*From:*ibis-macro-bounce@xxxxxxxxxxxxx
<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] *On Behalf Of *Mike
LaBonte
*Sent:* Wednesday, November 21, 2018 9:01 PM
*To:* ibis-macro@xxxxxxxxxxxxx <mailto:ibis-macro@xxxxxxxxxxxxx>
*Subject:* [ibis-macro] Usage Dep example
All,
Making an editorial pass through IBIS 7.0, I came across a
slightly technical question. The example for AMI Usage Dep has
AMI_Resolve setting the name of the analog model file based on
other inputs:
(Rx_model
(Reserved_Parameters
(AMI_Version (Usage Info) (Type String) (Value"7.0")
(Description"This is a v7.0 AMI file."))
(Resolve_Exists (Usage Info) (Type Boolean) (Value True)
(Description"Indicates whether the executable model implements
AMI_Resolve."))
(Model_Name (Usage In) (Type String) (Value"ignore_me")
(Description"IBIS model name"))
(Rx_Receiver_Sensitivity (Usage Out) (Type Float) (Range 0.0
0.0 0.01)
(Description"Value depends on OP_mode and data rate"))
(Init_Returns_Impulse (Usage Info) (Type Boolean) (Default
True)
(Description"Impulse response is returned"))
(GetWave_Exists (Usage Info) (Type Boolean) (Default True)
(Description"GetWave Exists"))
)
(Model_Specific
*(my_file (Usage Dep) (Type String) (Value
**"ignore_me.s4p**")*
* (Description **"Rx analog model. Value depends on
OP_mode**"))*
(my_corner (Usage In) (Type String) (Corner"Typ" "Min" "Max")
(Description"Informs the executable modelwhat[ML1] <#_msocom_1>
corner is selected by user"))
(OP_mode (Usage In) (Type Integer) (List 0 1 2 3)
(Description"Operation mode"))
…
)
)
In this example, the Rx analog model is represented with a
4-port Touchstone file specified by parameter my_file,
Both Rx_Receiver_Sensitivity and my_file depend on the
legacy IBIS model name, parameter my_corner, and parameter
OP_mode, which specifies the device operation mode.
Rx_Receiver_Sensitivity also depends on bit_time.
Parameters Model_Name, my_corner and OP_mode, having usage
type In, are included in both input parameter strings to
AMI_Resolve and AMI_Init. my_file is of usage type Dep,
and its dependency on Model_Name, my_corner and OP_mode is
resolved in AMI_Resolve, which returns the value of
my_file. Rx_Receiver_Sensitivity is of usage type Out, and
its dependency on Model_Name, my_corner, OP_mode and
bit_time is resolved in AMI_Init, which returns the value
of Rx_Receiver_Sensitivity.
My question is, now that we have Ts4File to formally specify
the name of an analog model file, should "my_file" above be
replaced by "Ts4File", which would also require moving it to
Reserved_Parameters? As it stands, this is not really a
legitimate example. It is the EDA tool that must know the
analog model to get the channel impulse response, and there is
no way an EDA tool should be using my_file, or any
Model_Specific parameter, for that. I can't think of any
example where a Model_Specific parameter would need to be
Usage Dep.
Mike
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