RE: [IBIS-Users] Pin name assignment


Subject: RE: [IBIS-Users] Pin name assignment
From: Frank Dunlap (fdunlap@netlogicmicro.com)
Date: Fri Jan 31 2003 - 10:02:20 PST


Thanks for your two cents, Bob. I do agree with you and Abdulrahman.
We have a case of having to deal with some "legacy" naming conventions.
The "#" is the only odd-ball character, so if we can slip that
one through, then we should be okay.

As we know, it's not as easy as one would think. As I recall, in HSPICE,
"#" is allowed, though "(" and ")" aren't. In cases where a netlist
includes busses with "(" and ")", I have converted those characters
to "#", for HSPICE. Of course, with busses, you may be able to just remove the
"(" and ")", if that doesn't cause a naming conflict. So, some wouldn't
consider "(" and ")" to be special, but they have to be dealt with, if
your target tool does not accept them.

Thanks for the feedback.

Still, specifically, for a trailing "#" in IBIS models, does anyone know of
a real problem?

Regards,

Frank

-----Original Message-----
From: Robert Haller [mailto:rhaller@sisoft.com]
Sent: Friday, January 31, 2003 9:44 AM
To: Frank Dunlap
Cc: arafiqsi@yahoo.com; Eric Hsu; ibis-users@eda.org
Subject: Re: [IBIS-Users] Pin name assignment

Frank you hit my Pet peeve,

I think when designers/engineers (module, asic, semiconductor and SI)
use special characters in signal names, pin names or node names they are
asking for trouble. Most CAD tools can elegantly deal with 'special
characters' like -+=!@#$%^&*() and operating system can even deal with
them if they are quoted or backslashed or whatever.

But inevitably somewhere in your entire process flow you will run into a
problem and consume wasted time debugging a problem that can simple be
avoided by using intelligent naming conventions.

My suggestion is when you start a project write a design guide that sets
up naming conventions and stick to them. Push back on those designs,
models, etc that use special characters that can easily be avoided.

my $0.02
bob

Frank Dunlap wrote:
> I think that the suggestion to stay with a-z and 0-9 characters (and to
> start the name
> with a-z) is a good, safe idea. I have seen cases, however, where IBIS
> models used
> a trailing "#' to indicated active low. Such signals show up in certain
> vendor's datasheets and
> their IBIS models. Isn't a good idea, though maybe not a requirement,
> to use the
> EXACT same name in the IBIS model as is used in the datasheet, as these
> vendors
> have done?
>
> So, though it's a great suggestion to use just a-z and 0-9, are there
> any known
> issues in using other characters, and, in this case, specifically, "#"?
>
> Thanks,
>
> Frank
>
> -----Original Message-----
> *From:* Abdulrahman Rafiq [mailto:arafiqsi@yahoo.com]
> *Sent:* Friday, January 31, 2003 12:07 AM
> *To:* Eric Hsu; ibis-users@server.eda.org
> *Subject:* Re: [IBIS-Users] Pin name assignment
>
> Hi Eric,
>
> I take it you are trying to create a pin list for an ibis file. You
> can find information on this in the IBIS Information Specification
> Ver 3.2 http://www.vhdl.org/pub/ibis/ver3.2/ver3_2.pdf
>
> The number of characters allowed per column in the pinlist section
> of the ibis model are as followed:
>
> [Pin]: Max 5 characters allowed
>
> signal_name: Max 20 characters allowed
>
> model_name: Max 20 characters allowed
>
> R_pin: Max 9 characters allowed
>
> L_pin: Max 9 characters allowed
>
> C_pin: Max 9 characters allowed
>
> I would suggest avoiding using symbols other than integers
> (1,2,3,...) and letters (A,B,C,...) in in the [Pin] column.
>
> See the document in the link specified above, it show a sample
> pinlist section.
>
> Hope this helps.
>
> Thanks,
>
> Abdulrahman Rafiq
>
> arafiqsi@yahoo.com <mailto:arafiqsi@yahoo.com>
>
> */Eric Hsu <ehsu@netlogicmicro.com>/* wrote:
>
> Hi all,
>
> When assigning for pin name, I am not sure there is any limits
> except column length. of character. For example, if naming by
> "#", "", "(xxx)", "!", or even "%"? In case they can pass by
> "ibischk3", does it also mean they are acceptable by any
> commercial simulation tool as long as it can accept IBIS format?
>
> Best Regard,
>
> Eric
>
> NetLogic Microsystems, Inc.
>
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-- 
Robert J. Haller (rhaller@sisoft.com)
Principal Consultant
Signal Integrity Software Inc.
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