Arpad,
You may be correct about node 0 on the .subckt definition line, but I do not
see that restriction in IBIS-ISS.
However, the examples are changed in the .subckt nodes such that VXX is the
same as node 0 with this line.
VXX VXX 0 0.0
(node 0 is inside)
Bob
From: ibis-interconn-bounce@xxxxxxxxxxxxx
[mailto:ibis-interconn-bounce@xxxxxxxxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Tuesday, November 28, 2017 5:38 PM
To: Bob Ross; 'IBIS-Interconnect'; ibis-macro@xxxxxxxxxxxxx
Subject: [ibis-interconn] Re: Proposed changes on reference connections for
BIRD189
Bob,
I think node 0 and its synonyms are not allowed on .subckt definition lines.
So a lot of your examples fall out for that reason. Could you rewrite your
questions without them?
Thanks,
Arpad
======
Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------
From: Bob Ross <bob@xxxxxxxxxxxxxxxxx>
Date: 11/28/17 6:58 PM (GMT-06:00)
To: 'IBIS-Interconnect' <ibis-interconn@xxxxxxxxxxxxx>,
ibis-macro@xxxxxxxxxxxxx
Subject: [ibis-interconn] Re: Proposed changes on reference connections for
BIRD189
All,
Questions and comments.
1. The EDA tool may already have a node 0 reference terminal. That becomes
a "virtual reference" everywhere, whether or not there is a corresponding
physical terminal.
2. The stated rule is:
"Terminal_type A_gnd is not required under File_TS or File_IBIS-ISS. If
present under File_TS, it may be used only once on the N+1th terminal line.
If present under File_IBIS-ISS, it may be used any number of times on any of
the terminal lines."
For File_IBIS-ISS, we should not have any qualifiers or values. Whereever
A_gnd is declared, it a global reference terminal. For example, nodes at
locations 5 and 7 are "0" would have these terminals without any qualifiers:
Consider
.subckt model_name io vdd vss vdd1 VXX vee1 VXX
Case 1 - only node "0" are declared with A_gnd (to occupy a position)
5 A_gnd
7 A_gnd
Case 2 Actual nodes are electrically shorted by connections to node 0
5 Pullup_ref signal_name VDD | this is correct for ECL relative to
| global GND).
7 Pulldown_ref signal_name VSS
Case 3: Use A_gnd to short an existing rail to global ground:
3a
2 A_gnd : existing non-node 0 nodes
3 A_gnd
5 A_gnd
7 A_gnd
Or 3b
2 A_gnd
3 A_gnd
5 Pullup_ref signal_name VDD
7 Pulldown_ref signal_name VSS
Case 4:
No internal node "0" node
.subckt model_name io vdd vss vdd1 VSS1 vee1 VEE2
5 A_gnd
7 A_gnd
----
An expected connection is shown in Case 1.
Do we allow IBIS-ISS node "0" connections with any other rail Terminal_type
besides A_gnd? (Case 2, 3b)
Do we allow IBIS-ISS A_gnd Terminal_type designation for any rail node that
is not node "0"? (Cases 3, 4)
If so, why not for terminals 1 .. N in Touchstone?
Do we allow IBIS-ISS A_gnd Terminal_type designation to any rail terminal
that is not node "0" AND there is no node "0"? (Cases 4)
If so, why not for terminals 1 .. N in Touchstone?
I think the stated rule allows all four cases, but not the Touchstone
exception.
Bob
-----Original Message-----
From: ibis-interconn-bounce@xxxxxxxxxxxxx
[mailto:ibis-interconn-bounce@xxxxxxxxxxxxx] On Behalf Of Muranyi, Arpad
Sent: Tuesday, November 28, 2017 1:32 PM
To: IBIS-Interconnect (ibis-interconn@xxxxxxxxxxxxx);
ibis-macro@xxxxxxxxxxxxx
Subject: [ibis-interconn] Proposed changes on reference connections for
BIRD189
Hello Everyone,
I am sending this to both email reflectors to make sure no one is left out.
As most of you may already know, I made a proposal in today's ATM
teleconference on how to modify BIRD189 to take care of the reference
connections for File_TS and File_IBIS-ISS. Based on the discussions and
suggestions in the ATM meeting today, I prepared a new draft of BIRD189
which is in the attachment. This is based on the most recent
"bird189.5_draft11_v1.docx" file. I accepted all changes and created a new
file with tracking turned on, so that my proposed text could be found
easily. This is now called "bird189.5_draft11_v2.docx" and is in the
attachment.
I understand that there may be a few other places which may need updating,
such as the tables, but I will leave that up to people who are more familiar
with the editorial procedures on the document. Also, I think we should
agree to this proposal first before making far reaching changes to the rest
of the document.
Please review this proposal before the Interconnect teleconference tomorrow.
I hope that we should be able to get this topic behind us in the meeting
tomorrow.
Questions, comments are welcome, as always...
Thanks,
Arpad
===================================================================
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