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- -f filename
This mandatory argument specifies the input source for batch net
extraction. the filename can be a path to a layout file in a
supported format, the access name of a CHD in memory, or a path to a
saved CHD file.
The technology file in use must match the source file, with the
extraction parameters and keywords properly set up.
- -c cellname
This provides the name of the top-level cell for extraction. If not
given, the top-level cell used will be either the cell configured into
the CHD source, if any, or the lowest-offset top-level cell found in
the source layout file.
- -g gridsize
This argument is mandatory if -w is not given. It sets the grid
size, in microns. The choice of a grid size is machine and layout
dependent. The objective is to choose as large a grid as possible,
without exceeding memory limits or causing excessive page-swapping.
For small layouts, it is fine to give a very large grid size to force
use of only one grid cell. In general, some experimentation may be
required to find the ``best'' grid size. A starting point of 400
microns may be reasonable.
- -v
If given, via objects will be included in the netlist cells and files.
Via layers are the layers with the Via keyword given in the
technology file. The objects on these layers are clipped to the
intersection areas of the two associated conductors.
- -v+
This is similar to -v, but in addition the ``check layers'' (if
any), clipped to the via object, will also be included in net cells
and files. The check layers are the layers used in the optional layer
expression supplied on the Via line. This expression must be
``true'' for a via object to actually represent a connection. With
-v given, the included vias are those that pass the check
criteria, but the check layers are not included. With -v+, the
check layers will be included.
If the generated netlist file is read back into Xic and extraction
run, the -v+ option will allow the nets to be correctly
re-extracted. If the check layers are missing, this may fail, and
extraction would certainly fail if vias are not included at all.
- -w l,b,r,t
If a window is given, a grid size should not be given. In this case,
there is no grid, and the rectangular area given, as comma-separated
dimensions in microns, is read into memory and processed as if it were
a grid cell. The OASIS file is produced, but there are no edge files,
and no Stage 2 or Stage 3 steps.
- -b basename
This supplies a basename for the generated files. It can have a path
prefix, which will cause the generated files to be written in the
given directory, which must exist. If this argument is not given, the
name of the top-level cell is used as the basename.
- -nf
By default, in Stage 3 processing, the net cells will be flat. If
this argument is given, subnets will appear is cell instances in the
``primary'' net cell.
- -nc
This will turn off compression in OASIS output files. This is not a
good idea, unless compression is not supported by the reader.
- -ne
This turns off the part of the extraction that recognizes device
structures, leaving only conductor grouping for connectivity
determination. This may be fine fo some applications, and avoids
computation. In MOS circuits, for example, if the Active layer is
assumed to be a conductor, then all FETs will be shorted, drain to
source. However, using an EXCLUDE directive for Poly on Active should
fix this.
- -l
If this is given, when the flat data are read into memory for
processing, any existing layer filtering is kept. Without this
option, when -ne is not given, all layers are read since these
may affect device recognition. When -ne is given, only
CONDUCTOR and VIA layers are read.
- -k
If given, all working files are retained. Without this option, edge
files, etc. are deleted when no longer needed.
- -s1
If given, the operation will stop at the end of Stage 1.
- -s2
If given, the operation will stop ath the end of Stage 2.
The grid cells are assigned x,y index numbers, according to position,
with the 0,0 cell located in the lower left corner. The cells are
traversed left to right by row, from bottom to top. Each net in a
grid is assigned a number, which is the group number from extraction.
All three numbers are non-negative, and the triplets represent a
unique designation for a subnet. The net cells in the Stage 1 OASIS
files files are names ``x_y_n'', i.e., the three numbers
separated by underscores.
In the final OASIS file, the net cells are renamed n1, n2,
..., replacing the triples with an index number. If instantiation is
used, the subnet cells that are not primary nets retain ther original
names. The primary subnet from among a group of connected subnets is
the one that is lowest in ``traversal order'', which is the lowest
group number in the first grid cell seen in a sweep left to right in
the rows, ascending in y.
Next: The !addcells Command: Add
Up: The !netext Command: Batch
Previous: Stage 3
Contents
Index
Stephen R. Whiteley
2012-04-01