All,
We do not need to change the syntax for devices with missing modeling
information or that have functionality not supported by IBIS.
We just document it as a .ibs model with at least a [Pin] listing. The name
might be the name of the actual device name with perhaps a suffix such as
"_STUB" This would indicate that more information may be required.
For example,
Mux8 NA SN74CBT3251_STUB
The "_STUB"s would be listed in the [Note]s area for easy search and
replacement and for filling out the actual model details. The minimal stub
would have a [Pin] listing, even if all of its pins are NC or stubbed out be
Terminator model. Some pins may not be possible to model by IBIS, or may
require active multi-lingual elements that not every EDA tool can support.
The EMD can still provide routing to the STUB models from CAD data bases
because all of the stubbed pins are in the [Designator Pin List]. Some pins
with unusual functions can be listed as NC. This allows for the extraction
of the EMD net list, as might be extracted from a CAD data base.
Bob
From: ibis-interconn-bounce@xxxxxxxxxxxxx
[mailto:ibis-interconn-bounce@xxxxxxxxxxxxx] On Behalf Of Bob Ross
Sent: Wednesday, March 25, 2020 1:43 PM
To: 'IBIS-Interconnect'
Subject: [ibis-interconn] Re: "NA" changes to [EMD Parts]
All,
Attached is an IBIS model that I had fun creating: (sn74cbt3251.ibs)
CBT switches have been supported by IBIS since Version 3.0 and are supported
by EMD as .ibs files. The EDA tool needs to select one row of [Series
Switch Group]. In this case, the signal_name at A gets connected to one of
B!..B8 or disconnected. Pin_number routing for Pin_I/O terminals are still
valid. Also, the attached cbt.ibs file shows another variation where a bank
of terminals are straight thru or cross-over. I believe one [EMD Group]
with a model that contains all of the I/O signal names would be sufficient.
BUG206 shows a test case CBT model to illustrate a minor problem.
Other parts that do fit in with IBIS may still have a file reference and
component name, but some analog terminals might just be NC or stubbed out as
Terminator models.
Bob.
From: ibis-interconn-bounce@xxxxxxxxxxxxx
[mailto:ibis-interconn-bounce@xxxxxxxxxxxxx] On Behalf Of Walter Katz
Sent: Wednesday, March 25, 2020 10:32 AM
To: IBIS-Interconnect
Subject: [ibis-interconn] "NA" changes to [EMD Parts]
All,
Keyword: [EMD Parts]
Required: Yes, if [Designator Pin List] is defined below
Description: Maps an EMD part to an IBIS component or EMD module.
Usage Rules: The [EMD Part Map] keyword must be followed by a list of all
the EMD parts (also called part numbers or part names in industry). Each
EMD part is followed by the file reference of a .ibs [Component] name, .emd
[Begin EMD] name or NA NA. While official data book names of parts are
recommended, this is not required.
For the context in this Electrical Module Description section, a "part"
declaration shall be one data line under [EMD Parts].
A part that is an .emd file can itself reference an EMD module. This shall
be limited to 6 hierarchy levels of nested .emd files.
An EMD file may not reference itself directly or indirectly.
The EMD part, file reference, and component/define module name terms are
separated by white space.
The EMD part is limited to forty characters.
Every part referenced in the EMD Designator List shall have one and only one
entry in this list of parts.
Parts that are followed by NA NA are parts that are not used, or are analog
or digital parts (e.g. power converters, buffers, muxes , .). It is
recommended that the model maker adds comments to these lines to help the
EDA tool determine what models should be used for any terminals that connect
to designators that have such parts.
Example:
[EMD Parts]
|
| EMD Designator File reference Component/Define Module
Processor pp100.ibs Processor
Memory_16X8 simm.emd 16X8_SIMM
74LS244a ls244.ibs NoName_74LS244a
Res_10K r10K.ibs My_10K_Pullup
Mux8 NA NA | This is a 1x8 Mux
(e.g. TI SN74CBT3251)
[End EMD Parts]
Walter
Walter Katz
wkatz@xxxxxxxxxx
Office 978.461-0449 x 133
Mobile 720.417-3762