Hierarchical scan architecture for design for test applications
First Claim
1. A computer readable medium containing instructions that when executed implement a method of inserting scan resources into an integrated circuit design, said method comprising the steps of:
- a) accessing user defined specification commands defining scan configurations that indicate a manner in which scan chains are to be constructed and define scan structures to be used in constructing said scan chains;
b) generating a scan plan based on said design and based on said specification commands without altering logic within said design, said step b) further comprising the steps of;
b1) partially constructing scan chains within said scan plan according to said specification commands;
b2) identifying scan structure within said design not covered by said specification commands; and
b3) completely constructing said scan chains within said scan plan based on said scan structure identified in steps b1) and b2) to generate balanced scan chains; and
c) synthesizing said scan plan within said design by inserting scan resources into said design to realize said balanced scan chains, said step c) storing information in computer memory for use by a computer system in the production of an integrated circuit device of said integrated circuit design.
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Abstract
A system and method for architecting design for test circuitry (e.g., scan architecting) within an integrated circuit design having subdesigns (e.g., modules). The novel system contains a default operational mode (no user specification) and an operational mode based on user specifications; within either mode, the system recognizes and allows definition of subdesign scan chains which can be linked together alone or with other scan elements to architect complex scan chains (e.g., top level scan chains). The system includes specification, analysis, synthesis and reporting processes which can be used in an IC design having a hierarchical structure including modules. The specification process accesses a design database and a script file and allows a user to define global scan properties (scan style, number of chains, etc.), properties of a particular scan chain (membership, name, etc.), test signals (scan-in, scan-out, scan-enable, etc.), complex elements used as part of a scan chain without requiring scan replacement, wires and latches forming connections between scan elements; this information is associated with the selected design database. Analysis reads the design database and performs architecting of scan chains based on inferred scan elements of the design and defined (e.g. specified) scan elements. During analysis, the logic within the design database is not altered and a script is generated for user modification/verification. Specification and analysis can be executed iteratively until the desired scan structures are planned. Synthesis then implements the desired DFT circuitry by altering the design database based on the scan chains planned by analysis.
117 Citations
20 Claims
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1. A computer readable medium containing instructions that when executed implement a method of inserting scan resources into an integrated circuit design, said method comprising the steps of:
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a) accessing user defined specification commands defining scan configurations that indicate a manner in which scan chains are to be constructed and define scan structures to be used in constructing said scan chains; b) generating a scan plan based on said design and based on said specification commands without altering logic within said design, said step b) further comprising the steps of; b1) partially constructing scan chains within said scan plan according to said specification commands; b2) identifying scan structure within said design not covered by said specification commands; and b3) completely constructing said scan chains within said scan plan based on said scan structure identified in steps b1) and b2) to generate balanced scan chains; and c) synthesizing said scan plan within said design by inserting scan resources into said design to realize said balanced scan chains, said step c) storing information in computer memory for use by a computer system in the production of an integrated circuit device of said integrated circuit design. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A computer readable medium containing instructions that when executed implement a method of inserting scan resources into an integrated circuit design, said method comprising the steps of:
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a) accessing user defined specification commands defining scan configurations that indicate a manner in which scan chains are to be constructed and define scan structures to be used in constructing said scan chains, wherein said specification commands include a specification command defining a scan segment, said scan segment including a member list of sequentially coupled scan cells and access points to said member list, said access points including a scan in and scan out; b) generating a scan plan based on said design and based on said specification commands without altering logic within said design, said step b) further comprising the steps of; b1) partially constructing scan chains within said scan plan according to said specification commands; b2) identifying scan structure within said design not covered by said specification commands; and b3) completely constructing said scan chains within said scan plan based on said scan structure identified in steps b1) and b2) to generate balanced scan chains; and c) synthesizing said scan plan within said design by inserting scan resources into said design to realize said balanced scan chains, said step c) storing information in computer memory for use by a computer system in the production of an integrated circuit device of said integrated circuit design. - View Dependent Claims (9, 10, 11, 12, 13)
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14. An apparatus for inserting scan resources into an integrated circuit design comprising:
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a) means for accessing user defined specification commands defining scan configurations that indicate a manner in which scan chains are to be constructed and define scan structures to be used in constructing said scan chains; b) means for generating a scan plan based on said design and based on said specification commands without altering logic within said design, said means for generating a scan plan comprising; b1) means for partially constructing scan chains within said scan plan according to said specification commands; b2) means for identifying scan structure within said design not covered by said specification commands; and b3) means for completely constructing said scan chains within said scan plan based on said scan structure identified in said means for partially constructing and said means for identifying scan structure to generate balanced scan chains; and c) means for synthesizing said scan plan within said design by inserting scan resources into said design to realize said balanced scan chains, said means for synthesizing also for storing information in computer memory for use by a computer system in the production of an integrated circuit device of said integrated circuit design. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification