RE: [IBIS-Users] [Pin Mapping] for input models

Hi Arpad,

many thanks for answer!

I would say that IBIS specs are not 100% clear on that place, because
for input buffers there should not be any connection required, because
it has only power and ground clamps. Perhaps for next IBIS version in
specs could be written one example for input buffer so questions like
this my could be avoided.

Many thanks,
Radovan

-----Original Message-----
From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On
Behalf Of Muranyi, Arpad
Sent: Friday, November 18, 2005 9:37 PM
To: ibis-users@eda.org
Subject: RE: [IBIS-Users] [Pin Mapping] for input models

Radovan,

The IBIS specification says that you should use NC.

| Each line must contain either three, five or six entries.
| Use the reserved word NC where an entry is required but a bus 
| connection is not made (see below).

NC for the pulldown and pullup references doesn't mean that the buffer
model has them, you just are not connecting them.  It means that you are
not making a connection to those rails for whatever reason, which in
your case is that they don't exist for your input model.

Arpad
===============================================

-----Original Message-----
From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On
Behalf Of Radovan.Vuletic@infineon.com
Sent: Friday, November 18, 2005 7:42 AM
To: ibis-users@eda.org
Subject: [IBIS-Users] [Pin Mapping] for input models

Hi IBIS experts,

I have a question considering using [Pin Mapping] for input models.
Question would be: how many entries should be for input buffer in for
[Pin Mapping] keyword?

Specification says: "Each line must contain either three, five or six
entries." (Btw., in specification there is no example for input buffer)

Format of command is: [Pin Mapping] pulldown_ref pullup_ref
gnd_clamp_ref power_clamp_ref ext_ref

So if I write for example:

A1 GND VCC

There are only 3 entries, but according to format specification second
and third entry are used for pulldown reference and pullup reference
respective, what is a nonsense in this case, because input buffers have
only power and ground clamps and no pull-up and pull down references.

If I write something like:
A1 NC NC GND VCC

This according to my opinion makes more sense, but still I have to use
NC for pull-up and pull down references.

What I was able to find as an example on Internet had always 5 entries,
like:
A1 GND VCC GND VCC

For me this is senseless, because, as said before, one input buffer has
only power and ground clamps.

So, can somebody write me what is a proper format for input buffer in
[Pin Mapping] ?

Thanks,
Radovan
 



Best regards / Mit freundlichen Gru?en / S postovanjem Radovan Vuletic

Infineon Technologies AG
MP PD PDE
Room 03.911
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D-81541 Munchen

Phone:		+49 (0)89 234 20108
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Fax (PC):	+49 (0)89 234 955 5305 

E-mail: radovan.vuletic@infineon.com

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