Re: Connector spec swathing

To All:

In response to a number of comments concerning algorithms for
processing swath matrices, here is an algorithm to map the
swath information into a larger swath or into the full-sized
connector.

The algorithm assumes that the internal connector coupling
topology is uniform for the internal structure of the connector
and that the left of center and right of center topologies of
the connector are the same as the corresponding left of center
and right of center topologies of the swath.

Because the IBIS matrices symmetrical about the diagonal
(circuit theory symmetry) the coupling topology is always from
a given pin looking forward. The resulting connector matrix is
banded to the same bandwidth as the swath matrix (which itself
could have a bandwidth corresponding to its total number of pins
or less, depending on its coupling topology).

This approach could be also be used to map smaller Spice
netlists for swath sections into larger Spice netlists covering
more pins.

(Also, this approach could be generalized into a matrix
expansion language that accounts for non-uniform sections,
missing pins, cutout sections, but based on a set of "consistent"
swath matrices S1, S2, ... that describe the variations
from the standard standard Swath S, but the details and
requirements would have to be defined.)

Bob Ross
Mentor Graphics

SWATH MATRIX PINS = S
CONNECTOR MATRIX PINS = C

I. - One Dimensional Column Mapping: (Swath Rows = Connector Rows)

    Center column (or left of center for even number of columns)
    |
    |

S S S S S
S S S S S
....
S S S S S

| | | | +---------------+
| | | +---------------+ |
| | +---------------+ | |
| | | | | | | ... | | | |

C C C C C C C ... C C C C
C C C C C C C ... C C C C
....
C C C C C C C ... C C C C

1 1 2 ............. 2 3 3 <--- Mapping Notes:

  1 - Direct Mapping of the Left Side Swath Coupling Topology
  2 - Center Swath Coupling Topology Column mapped into each connector
      column, stepping one column at a time
  3 - Direct Mapping of the Right Side Swath Coupling Topology

II. - Two Dimensional Row and Column Mapping: (Swath Rows less than
      Connector Rows)

Step 1. Create Temporary Swath with Same Number of Rows as Connector using
        Approach similar to I., but applied to Row Expansion (instead of
        Column Expansion).

Step 2. Use Temporary Swath for Column Expansion using Approach I.
Received on Thu Jun 15 11:48:55 2000