.NH
A Toy Example.
.LP
In this section we present a complete example.  The design consists of
two
.SM I/O
connectors that route signals from a ribbon cable to a backplane.
Here is the schematic, followed by the
.CW ".w"
file:
.PS <toy.pic
.nr dP 2	\" delta point size for program
.nr dV 2p	\" delta vertical for programs
.P1
.so toy.w.l
.P2
.LP
The comments (introduced by
.CW % )
are coordinates from the
.CW .g
file that can be used later to annotate the drawing with pin numbers.
Otherwise the
.CW .w
file is mostly just a compendium of the text strings in the
.CW .g
file.
In order to proceed further, we need a
.CW .pins
file:
.P1
.so toy.pins.l
.P2
.LP
It should be fairly obvious what is going on here.  Note the appearance of the
.I "package type"
on the
.CW .t
lines.
Now the
.CW .wx
file can be made:
.P1
.so toy.wx.l
.P2
.LP
This is basically a listing, for each chip, of net\ name\-pin\ number pairs.
Package types are copied through from the
.CW .pins
file for use by the physical design tools, and
the pin names are left as an aid to humans.