GDSII STREAM FORMAT PDF
May 26, 2020 | by admin
In the design of integrated circuits, the most popular format for interchange is the Calma GDS II stream format (GDS II is a trademark of Calma Company, a wholly . Portions of the GDSII Stream Format Manual, Documentation No. B97E, Feb. , reprinted with permission of Cadence Design Systems, Inc., River. GDS II is a database file format which is the de facto industry standard for . The GDSII or Stream file format stores its information in records.
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There is a section below with hexadecimal values of the various record types and a brief description of the types. I doubt anyone has had the chutzpah to start using it since.
If your layout has more than layers, some of these can be re-mapped to appear on the same GDSII layer. This number must be at least 2 and not more than Neither the number of columns nor the number of rows may exceed 32, decimal and both are positive.
In some cases, this name does not match that of the imported file. This marks the end of an element. This is despite the fact that GDSII is not an open industry standard — it tsream developed by Calma in the 80’s and the ownership of the specification moved from Calma to GE to Valid to Cadence over the years. When Holes As Polygons is not selected, polygons with holes are translated as single-segment polygons, the false edge segment becoming part of the polygon.
Bit 0 leftmost specifies reflecton. In formaat AREF of course. The program stores arcs as true arcs.
GDSII – LayoutEditor Wiki
The first is the number of columns. No data is present. End of library token An example of a common record order see below for record descriptions follows: Square ended paths 1: This marks the end of a structure.
There is no explicitly stated limit to the level of hierarchy the degree of cell nesting ; however, most CAD programs impose a limit of around 32 levels.
To calculate the size of a user unit in meters, divide the second number by the first. GDSII further employs user units in terms of number of user units to a meter. One or more Stream records 3. Some systems may not be able to tolerate this type of complex polygon. Real numbers are not represented in IEEE format. Each name is padded with nulls if it is shorter than 44 bytes. This information is used only when reading the data into a new library.
The elegant architecture enables it to support today’s modern chips with their billions of polygons while the simplicity enabled programmers to write code to manipulate GDSII and do things with it that the developers could not have imagined. Possible types and values are: A polygon exceeding this limit will be split by default.
Path and boundary elements may have up to pairs of coordinates. For a step-by-step tutorial, see Importing a Layout. Sort of an “include” element. This is done by adding an additional cell to the design with the fromat LayerNames that contains a text elements on each layer with the layer names. The least significant bit of the most significant byte is the plexhead flag.
This record must not be present if streak of the fonts have a textfont file. The Advanced Design System reads GDSII files into a layout design without circuit or schematic information, internally converting the drawing data to the current layout units.
GDSII Stream File Translator
This option is rarely needed and the default for this function is off. The value of the number is defined to be mantissa 16 exponent.
The 7 least significant bits of the first byte are the exponent in “excess 64” notation. The first and last point of a boundary must coincide. This option is useful when your post-processor does not support or correctly translate hierarchy in GDSII Stream files.
GDS II (Calma GDS II)
There are values for such things as the beginning of a structure, the beginning of a boundary, the end of a structure, and so on. The first two numbers in brackets are the record type and the last two numbers in brackets are the data type see the table above.
Colors, and style of the layer are stored as attributes of the text element. Cells may contain geometrical objects such as polygons boundariespaths, and other cells. GDSII has some limitations that may affect your layout, including: In the MASK list, data types are separated from the layers witha semicolon.
Various companies including Artwork have developed their own gdsii binary-ascii converters for those who wish to use tools such as Perl, awk or Python to manipulate GDSII data.
A header record 2. In strewm units, may be negative. Bits 10 and 11, taken together as a binary number, specify the font.