[ibis-interconn] [Interconnect Port Groups]

From: "Walter Katz" <wkatz@xxxxxxxxxx>
To: <ibis-interconn@xxxxxxxxxxxxx>
Date: Wed, 9 Apr 2008 10:15:26 -0400
All,

I feel very strongly that Touchstone-2 includes [Interconnect Port Groups],
and that it should be enhanced to include differentials.

Please note, that with the following scheme, it is a very straightforward
procedure to automatically create mixed mode s parameter data automatically
for the normal s parameter data (at least for near/far end differential
interconnect). I do not know if it makes sense this can be used to specify
things like 3 port differential, s parameter data that does not represent
near/far end interconnect.

I extended [Interconnect Port Groups] to include shorthand notation for the
common interconnect uses of s parameters (NFNF and NNFF), and for these
special cases as differentials.

I indicated two cases (search for ?Help?) of a Group that has no ?:?, and
there for no near and far end, and a Group that had more that two ports at
each end. We can either make these illegal, or someone might want to expand
on what they might mean.

Walter


[Interconnect Port Groups]

*       The [Interconnect Port Groups] keyword is optional.
*       The [Interconnect Port Groups] keyword is followed by one or more 
Groups.
*       A Group is delineated by an open and matching close parenthesis.
*       A Group may or may not contain one colon.
*       A port is a number between one and the number of ports (Nports) in the s
parameter matrix.
*       White space, tab and comma are legal port delimiters between a colon 
and a
parenthesis.
*       If a Group contains a colon:
*       The colon separates near end and far end ports.
*       The near end ports (s) are on the left side of the colon, and the far 
end
ports (s) are on the right side of the colon.
*       The same number of ports must appear on both sides of the colon.
*       If more than one ports are on both sides of the colon, then the order of
the ports on the left and right side of the colon are important.
*       If there are two ports on both sides of the colon:
                *       The first port on each side is the active high side of 
a differential
pair.
                *       The second port on each side is the active low side of 
a differential
pair.
*       If there are more than two ports on both sides of the colon:
                *       Help ? I do not know if this should be allowed, or what 
this could mean.
*       If a Group does not contain a colon:
*       Help ? I do not know if this should be allowed, or what this could mean.
*       Each port must appear once in one and only Group.
*       The following shorthand notations shall be allowed
*       [Interconnect Port Groups] NFNF
                *       The number of Nports must be even.
                *       NFNF is equivalent to
                        *       (1:2) (3:4) (5:6) (Nports-1: Nports)
*       [Interconnect Port Groups] NNFF
                *       The number of Nports must be even.
                *       NNFF is equivalent to
                        *       (1:1+ Nports/2) (2:2+ Nports/2) ?(Nports/2: 
Nports)
*       [Interconnect Port Groups] Differential_NFNF
                *       This applies to s parameter data that contains only 
differential pairs.
                *       The number of Nports must be divisible by 4.
                *       Differential_NFNF is equivalent to
                        *       (1 3:2 4) (5 7:6 8) ? (Nports-3, Nports-1: 
Nports-2, Nports)
*       [Interconnect Port Groups] Differential_NNFF
                *       This applies to s parameter data that contains only 
differential pairs.
                *       The number of Nports must be divisible by 4.
                *       Differential_NNFF is equivalent to
                        *       (1,1+ Nports/2:2:2+ Nports/2) ?(Nports/2-1, 
Nports/2: Nports-1,Nports)
[ibis-interconn] [Interconnect Port Groups]

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