specification for a facet that describes a family of pads, to be used with
padp.

Padp has the ability of implementing formal terminals of a chip using pads 
from a user-specified family. padp will match type and direction of the formal terminal.

padp also will take into account power consumption of the pads to determine how many 
power and ground terminal to add to the  chip bejond those already present in the chip.

A pad family can be of two types: instances (the ``normal'' type) or connectors.

Current limitations: 
Only 1 power voltage is supported. Tristate outputs are not supported yet.


A facet decribe the family must contain:

VIEWTYPE = SYMBOLIC
EDITSTYLE = SYMBOLIC

One instance of each pad. The instances should be attached to
INSTANCES bag or to the CONNECTORS bag according to the type of the family.

 The instances should be rotated so that they
can be placed on the top of the chip (inner edge facing down).
Each instance should be annotated with the property DIRECTION (INPUT,
OUTPUT, INOUT) and TERMTYPE (SUPPLY, GROUND, CLOCK , SIGNAL).
Also each instance must have the real valued property
PAD\_VDD\_GND\_REQUIRED, expressing the amount of power required by
the pin. For example: Suppose that the for a particular family, one
should put one vdd/gnd pair for each 4 output pads. This will be
expressed by attaching to the output pad the property
PAD\_VDD\_GND\_REQUIRED with value 0.25 = 1/4.

One net called PAD\_BONDING\_PINS containig all the bonding pins,
which will give the implementation to the formal terminals.

One net called PAD\_INTERNAL\_PINS containing all the bonding pins,
which will give the implementation to the formal terminals.

One net called PAD\_SUPPLY\_RING containing all the terminals that
must be connected to form the supply ring for the pads. The net should
also contain a path of the right width on the correct layer for the
ring.

One net called PAD\_SUPPLY\_RING containing all the terminals that
must be connected to form the supply ring for the pads. The net should
also contain a path of the right width on the correct layer for the
ring.

One property called PAD\_MINIMUM\_SEPARATION, to specify the minimum
distance between the pads. A separation of 0 means that the pads can
be abutted.
