Introduction

The ASM 3500 translator converts from GDSII to DXF and from DXF to GDSII. The programs consist of two parts: the user GUI which gathers the relevant information and the translation engine which actually does the work.

The GUI collects information such as the file name, output file, and conversion parameters and launches the engine with a command line; it also must build an ascii configuration file for the engine to read.

This app note describes how one would bypass the GUI and launch the engine directly; either from a script, framework or another program.

1. Run gscan.exe to get GDSII File Information

The gscan program "scans" the GDSII file and extracts all sorts of information needed by the converter including a list of structures, the structure hierarchy, and a list of layers with data. The output from gscan is an ascii file ending in the suffix .ssn. GSCAN must be run prior to running the gds2dxf translation engine because you will be referencing the scan file when launching the engine.

The gscan command line

gscan.exe <input file> <-max:max structures> -sh -sea -elmcnt -dtp <-o:output file>

where

input_file             is the GDSII input file name. use double quotes if
                       the path or name has spaces in it.

-sh                    show hierarchy

-sea                   calculate structure extents

-elmcnt                calculate number of elements per structure

-max:max               is the maximum number of structures. Default = 32000.

-o:output file         the scan output file name. It should be built in the form:
                       <input_file_name>.ssn.

Example

C:\wcad\asm3500\gscan.exe demo1.gds -sh -sea -o:demo1.ssn

To see the contents of a scan file click here

2. Create the Configuration File

The g2d engine reads an ASCII configuration file that contains layer mapping information and also translation controls. There are quite a few options, so details are available on the configuration page. A sample configuration file is shown below:

gds.cfg

ACADUNIT
1000
UM

GDSUNIT
1000
UM

SCALE_FACTOR
1.000000

TEXT_FONT
txt
txt
txt
txt


TEXT_STYLE
STANDARD
STANDARD
STANDARD
STANDARD

3. Run the g2d.exe Engine

The syntax for running the translation engine is shown below:

c:\wcad\asm3500\g2d.exe demo1.gds demo1.dxf TOPMOSTST -i:3,5,9,10,12 -cfg:gds.cfg -scan:demo1.ssn


where



"c:\wcad\asm3500\g2d.exe"        the full path to the translation engine. You need to
                                 double quote this if there are spaces in the paths
                                 or file names.

"demo1.gds"   		         the input GDSII stream file to convert. (suffix need
                                 not be .gds) If no path is specified, the program looks
                                 in the current directory for the file.

"demo1.dxf"                      the name (and path) of the output DXF file.

TOPMOSTST                        name of the structure to use. This can be the top level
                                 structure or some lower level structure. Note: structure
                                 names are always case sensitive. (You can get a list of
                                 all structures from the .ssn file)

-i:3,5,9,10,12                   list of layers to include. can also use the -x to specify
                                 layers to exclude. (layers with data are listed in the
                                 file)

cfg:gds.cfg                      the configuration file that controls the translation.

-scan:demo1.ssn                  the name of the scan file to use (generally you have just
                                 generated this using gscan.)

Notice that because all files referenced can use a full path name, the required files could be located anywhere on the system.