Subject: Re: Regarding IBIS

From: Matthew Flora <[email-masked]>
Date: Thu, 10 Dec 1998 12:05:59 -0100

Dear Kok Tong Tham,

>I am a Shinshu University student in Japan.
>I am interesting in IBIS modeling. I had read over the IBIS version 3.1 
>spec.but some keyword still annoying me. Could you explain to me in 
>detail regarding some keyword? 
>
>1)What meaning of model_name and function_table_group 
>  in the third and fourth column of keyword [Series Pin Mapping]? 
>  and how to define it?
>
>2)How to define and what meaning of keyword [Series Switch Groups}?
>
>3)What relation between keyword [Model] and [Model Selector]?
>
>4)How to define the Model_name in keyword [Driver Schedule]?
>  what relation between Model_name and keyword [Model]?
>  what actually keyword [Driver Schedule] means?
>
>5)How to define keyword [Pin Mapping]?

I am forwarding your questions to the IBIS Users Group e-mail reflector and
have added you to that reflector so that you will receive any discussions
raised by your questions.  One suggestion that I have is to look at
ftp://ftp.eda.org/pub/ibis/birds/index.html.  There you will see a list of the
proposed changes to the IBIS standard (past and present).  They may be of
interest to you since they contain explanations not found in the standard
itself.  For instance, BIRD 52 might be of help to you.

Regards,

Matthew Flora
IBIS Open Forum Secretary
(425) 869-2320 PH
(425) 881-1008 FAX
[email-masked]
HyperLynx, 17641 NE 67th Court, Redmond, WA 98052 USA

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From: "Muranyi, Arpad" <[email-masked]>
Date: Thu, 17 Dec 1998 10:23:00 -0800

Dear Kok Tong Tham,

I will try to answer one of your questions.

>3)What relation between keyword [Model] and [Model Selector]?

You need to use the [Model Selector] in cases when a pin of a device is
driven 
by a buffer which can have different characteristics based on some internal 
selection mechanizm.  A good example is a programmable buffer who's strength
can
be changed.  For a case like that you will have to make a different [Model]
for 
each strength of the buffer.  But the pin list of the IBIS model can only
call 
one [Model] (or model selector), that is why the [Model Seletor] is needed.

To sum it up, for buffers which can behave several different ways, you have
to 
make a different [Model] for each behavior.  You list these [Model]s in the 
[Model Selector] keyword.  The name of the [Model selector] is then used in
the 
pin list.