dsd13-gos / dsd-14=pdk / Lect05_06
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Title: The Base of the PDK
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1 CADENCE DESIGN SYSTEMS, INC.
Technology File and Display
Resource File
The Cadence ® design technology data defines the parameters used in design sessions.
DFII supports two database types, CDBA and OpenAccess. The technology file for one contains some differences from the other. Classes meant for use on CDBA but not on OpenAccess and, conversely, classes meant for use on OpenAccess but not CDBA are described in this lecture.
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Files Containing Technology Data
The technology file defines the materials and rules you use in your IC fabrication process.
The technology file contains:
•Layer definitions
•Device definitions
•Layer, physical, and electrical rules
•Place and route rules
•Rules specific to individual Cadence applications
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Files Containing Technology Data
The display resource file specifies how your layers appear on display devices. The display resource file contains:
•Display device definitions
•Definitions of colors, stipple patterns, line styles, and fill styles
•Definitions of display packets, which are collections of colors, stipples, and line styles associated with particular display devices. A display packet specifies how you want a layer to be represented on the monitor or by a plotter. The technology file assigns a display packet to each layer it defines. In other words, a display resource file assigns a display packet to a display device or plotter, and the technology file assigns a display packet to each layer it defines.
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Technology File Development
and Usage
•Creating an ASCII technology file with a text editor
•Compiling creates a binary technology file and generates the technology library defined by the technology file you compile (or multiple files you compile together). The technology library consists of the binary technology file (named techfile.cds on CDBA or tech.db on OpenAccess) and the device cellviews defined in the ASCII technology file.
•Checking ensures that the technology file data conforms to the requirements of the Cadence design applications.
•Attaching causes the design software to apply the technology library definitions and rules to the attached design library, cell, or cellview during a design session.
•Run a design session
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Technology File Organization
The technology file is organized into classes and subclasses. A class is a category in which data with related functions is grouped. Each class begins with the class specifier (for example, physicalRules), followed by a parenthetical enclosure containing subclass specifications (for example, orderedSpacingRules and spacingRules), which define class data and rules.
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Technology File Classes
•Definition classes provide definitions for design sessions.
•The Controls class, Layer Definitions class, Devices class,
Via Definitions class, and Site Definitions class are defintions classes.
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The Controls class (controls)
•Assigns values to parameters you can refer to in the rules you define
•Sets user read/write permissions on individual technology file classes.
The individual subclasses:
•Define parameters for use throughout the technology file (techParams)
•Define read/write permissions for technology file classes (techPermissions)
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The Layer Definitions class (layerDefinitions)
•Describes the layers you use in your designs. The individual subclasses:
•Define the layers that can be used to define a layer-purpose pair (techLayers)
•Define the purposes that can be assigned to layer-purpose pairs (techPurposes)
•List layer-purpose pairs in priority order (techLayerPurposePriorities)
•Define the display attributes of a layer (techDisplays)
•Specify user-defined properties for specific layer-purpose pairs (techLayerProperties)
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