Virtual interface representation of hierarchical symbolic layouts
First Claim
1. A method for symbolically representing a circuit layout comprised of a plurality of circuit elements, the circuit elements defined without geometrical values, the method comprising:
- a) defining at least one virtual cell containing a topological constraint model of a plurality of circuit elements, a virtual cell being either a virtual leaf cell or a virtual hierarchical cell;
b) creating at least one instance of a virtual cell, the virtual cell being either a virtual leaf cell or a virtual hierarchical cell;
c) defining at least one virtual cell interface between a pair of virtual cells, and at least one connectivity relationship between the pair of virtual cells; and
d) coupling a pair of instances of virtual cells with a virtual cell interface.
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Accused Products
Abstract
A method and system provide for the symbolic design of a symbolic layout of an integrated circuit using only the topological features of the cells of the layout, absent geometrical information. Virtual leaf cells define circuit elements, and virtual hierarchical cells combine virtual leaf cells and other virtual hierarchical cells into hierarchical arrangements using interface graphs. Virtual interfaces describe the connectivity and orientation relations between virtual cells. The interfaces inherit the definitional requirements of interfaces at lower levels. The symbolic layout is produced from a hierarchy of virtual cells using hierarchical compaction and routing technology.
107 Citations
22 Claims
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1. A method for symbolically representing a circuit layout comprised of a plurality of circuit elements, the circuit elements defined without geometrical values, the method comprising:
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a) defining at least one virtual cell containing a topological constraint model of a plurality of circuit elements, a virtual cell being either a virtual leaf cell or a virtual hierarchical cell; b) creating at least one instance of a virtual cell, the virtual cell being either a virtual leaf cell or a virtual hierarchical cell; c) defining at least one virtual cell interface between a pair of virtual cells, and at least one connectivity relationship between the pair of virtual cells; and d) coupling a pair of instances of virtual cells with a virtual cell interface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. In a computer system for the automated design of electrical circuits including a library of stored leaf cells representative of primitive circuit elements and hierarchical cells, a memory unit for storing data, a processor, and a layout database for storing a symbolic circuit layout having a plurality of cells, a design tool, stored in the memory unit and executable by the processor for symbolically representing the circuit layout, comprising:
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a first means, operatively coupled to the library, for receiving therefrom a stored cell, and defining a virtual cell from the stored cell and storing the virtual cell in the memory unit; a second means for defining and storing in the memory unit a virtual cell interface; a third means, operatively coupled to the memory unit for retrieving a virtual cell therefrom for creating and storing in the memory unit an instance of the virtual cell in the layout database; and a fourth means operatively coupled to the layout database for coupling instances of virtual cells, and storing the coupling in the memory unit, wherein the processor is operatively controlled by the first, second, third and fourth means in response to user specification. - View Dependent Claims (13, 14, 15)
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16. In a computer system for the automated design of electrical circuits including a processor, a cell library of stored cells representative of circuit elements, a layout database for storing a symbolic circuit layout having a plurality of cells, a plurality of memories, a design tool for symbolically representing the circuit layout using virtual cells including virtual leaf cells and virtual hierarchical cells, the design tool comprising:
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a virtual cell extractor, executable by the processor for creating a virtual cell containing a topological constraint model from a cell stored in the cell library, virtual cell extractor storing the virtual cell in a virtual cell memory; a virtual instance creator, executable by the processor for creating an instance of a virtual cell and storing said instance in the layout database; a virtual instance connector, executable by the processor for connecting a pair of instances of virtual cells with a virtual cell interface; and a virtual cell interface creator, executable by the processor for defining a virtual cell interface between a pair of virtual cells. - View Dependent Claims (17, 18, 19)
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20. In a computer system for the automated design of an electrical circuit, a cell library including a plurality of stored cells representative of circuit elements, at least one stored cell comprising:
an interface graph containing selected instances of non-primitive circuit elements, the interface graph defining a set of connectivity constraints between the selected instances.
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21. A method for symbolically forming a leaf cell comprised of selected circuit objects, the method consisting of the steps of:
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a) receiving a first input selecting circuit objects; b) receiving a second input defining a connectivity relationship between the selected circuit objects; c) receiving a third user input defining spacing constraints between the selected circuit objects to define a circuit element; d) defining an interface relationship between at least one pair of circuit elements; f) forming at least one hierarchical circuit element from at least one set of circuit elements; and g) defining an interface relationship between at least one pair of hierarchical circuit elements.
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22. A computer system for the automated design of electrical circuits and for symbolically representing the circuit layout, the system comprising:
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a stored library of stored leaf cells representative of primitive circuit elements; a layout database for storing a symbolic circuit layout having a plurality of cells; a memory unit for storing data; means for defining and storing in the memory unit a virtual leaf cell containing a topological constraint model of a primitive circuit element stored in the library of leaf cells; means for defining and storing in the memory unit a virtual leaf cell interface identifying a pair of virtual leaf cells, and at least one pin binding pair; means for creating and storing in the memory unit an instance of a virtual leaf cell in the layout database; means for coupling instances of virtual leaf cells, and storing the coupling in the memory unit; means for defining and storing in the memory unit a virtual hierarchical cell using an interface graph containing either a) instances of virtual leaf cells and virtual leaf cell interfaces coupling pairs of said instances, or b) virtual hierarchical cells and a virtual hierarchical cell interface coupling said instances; means for creating and storing an instance of a virtual hierarchical cell in the layout database; means for coupling instances of virtual hierarchical cells, and storing the coupling in the memory unit; and a processor operatively coupled to the library, the database, the memory unit, for selectively retrieving therefrom and storing selectively therein virtual cells, and virtual interfaces.
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Specification