Contents

Overview
• Introduction
• Applications
• Input
• Outputs
    GDSII
    Ansoft ANF
    Optimal XFL
    OEA Netan
 
Running NETEX
• command syntax
 
Proximity Nets
• What is a Proximity Net?
• Why Would I Need It?
• How it Works
 
When Net Names Collide
• Different Net Names
   on Same Conductor

• Separate Conductors
   with Same Net Name

• Log file reporting
 
Layers and Datatypes
• What is a GDSII Datatype?
• How to Separate Entities
   by Datatype
 
The Technology File
• Conductor Stackup
• Assigning Net and Node
   Names using Text Layers

• Conductor Name Mapping
 
The Configuration File
• Data Units
• Expansion
• Output Directory
• Temporary Directory
• Extraction Directives
     • All
     • Bycoordinate
     • ByName
 
Saving Intermediate Results
• The GDSII file with all nets
• How Last State is Saved
 
 

The NETEX Configuration File

The configuration file sets certain parmeters for NETEX and more importantly, lists the outputs you want NETEX to generate. There are different ways of specifying how you want the nets to be extracted.

Below you will see the various configuration file directives and a short description of how they work.

UNITS  UM

Sets all of the coordinate units in the file to UM. Other valid units are: MIL, MM, CM, INCH


EXPANSION  0.500000

For coupling caclulations sets the distance at which to "grab" coupled metal. This parameter is only needed when the -couplings option is used on the command line.


OUTDIR
/export/home/cad_util/netex/bin/examples
ENDOUTDIR

OUTDIR is the directory where output files (which could be large) are written. Make sure you have enough space based on the relative size of your input file.


TEMPDIR
/export/home/cad_util/netex/bin/examples
ENDTEMPDIR

TEMPDIR is the directory where intermediate temporary files (which could be large) are written.

Extract Directives

The most important command in the configuration file is the EXTRACT directive. This is used to define which nets to extract. There are several possibilities:

  1. EXTRACT ALL - this will find all physical nets in the GDSII file and create a unique output for each one.


  2. EXTRACT BYCOORDINATE - in this method the user specifies X,Y coordinates (for a particular layer) and NETEX finds the conductor covering that coordinate and extracts the net. You can specify many sets of coordinates.


  3. EXTRACT BYNAME - in this method the user lists a net name or names and the program uses a text layer to find the name - it then finds the conductor covering the name's reference point.


EXTRACT  ALL  nettest_all.gds
ENDEXTRACT
Directs extract to find all nets in the GDSII file and to output the entire results to the file called nettest_all.gds. Each net will be contained in its own structure....
EXTRACT  ALL  nettest_cpl.gds COUPLED
ENDEXTRACT
The COUPLED option indicates that for each net, netex should calculate the metal that "couples" to the net using the expansion distance parameter.
EXTRACT  BYCOORDINATE  nettest_coord0.gds
10 0.000000 0.000000 netx
ENDEXTRACT

the BYCOORDINATE option tells netex just to extract the net that sits on layer 10 at 0,0 and to call the structure in the output file netx. This might be useful if you had a pad opening coordinate and wanted the entire net connected to that pad.
EXTRACT  BYCOORDINATE  nettest_coord2.gds
10 45.700000 363.700000 netx
31 47.200000 367.652000 nety
ENDEXTRACT

in this example we have provided two coordinates on two separate layers. This is just to show that if you had a large list of coordinates you could easily specify them all in a single EXTRACT command.
EXTRACT  BYNAME  nettest_byname0.gds
NET5
ENDEXTRACT
in this example we are using a net name - the name is taken from text in the GDSII file. The technology file defines which layer(s) contain text that represents nets. So the netex program will scan the text layer until it finds the string NET5. It uses the reference point of the string to find the metal (on the layer specified in the tech file) and then extracts all connected metal.
EXTRACT  BYNAME  nettest_byname2.gds
net5*
ENDEXTRACT
in this example we are using a net name with a wild card which will extract all nets matching the wildcard spec.




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