RE: [IBIS] Question about keyword ordering

From: Bob Ross <bob@teraspeed.com>
Date: Mon Dec 16 2013 - 13:43:09 PST
Arpad:

The general rule is that there is no keyword ordering requirement as long
as keywords are scoped within the higher level keywords or sections.
 For example, the keywords under [Component] must be scoped by
[Component], but can be in any order.  So placing [Pin Mapping] ahead
of [Pin] is legal.

However, there are purposeful exceptions.

The File Header Section must appear first and the [IBIS Ver] keyword
must be the first keyword.  Proper keyword and subparameter
processing rules depend on the file version.  [Comment Char] is
and exception since it placed anywhere and multiple times
within a .ibs, .pkg or .ebd file.

Under [Model]:  the [Model Spec] and [Receiver Thresholds] (if used)
must be the first keywords because they are closely related to the
specification subparameters.  We chose to do this for visual inspection
convenience.

Under [Component]: [Node Declarations] must appear before any or
all [Circuit Call] keywords to define the nodes.

Under [Begin Package Model]: [Number Of Sections] (if used) and
[Number Of Pins] must appear before [Pin Numbers]. 

I cannot recall if there are any other rules, but all the existing rules are
handled by the ibischk5 parser and therefore can be handled by
any EDA tool.

Bob

-----Original Message-----
From: owner-ibis@eda.org [mailto:owner-ibis@eda.org] On Behalf Of Muranyi,
Arpad
Sent: Monday, December 16, 2013 12:20 PM
To: IBIS
Subject: [IBIS] Question about keyword ordering

Hello Everyone,

We ran across an IBIS file in which the [Pin Mapping] keyword
is placed before the [Pin] keyword.  It seems that the IBIS
parser is not complaining about this, as there are no errors.
I don't recall any requirements in the specification about the
order of the keywords.  On the other hand, if we want to make
it easier on the tools, it would make sense to have certain
keywords in a certain order.

Could someone comment on this?  Does the IBIS specification
really have no requirements about the order of these keywords?
Was this intentional or an oversight?

Thanks,

Arpad
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Received on Mon Dec 16 13:43:22 2013

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