Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
  • G01R31/28—Testing of electronic circuits, e.g. by signal tracer
  • G01R31/30—Marginal testing, e.g. by varying supply voltage
  • G01R31/3016—Delay or race condition test, e.g. race hazard test
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
  • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
  • G01R31/28—Testing of electronic circuits, e.g. by signal tracer
  • G01R31/317—Testing of digital circuits
  • G01R31/31705—Debugging aspects, e.g. using test circuits for debugging, using dedicated debugging test circuits
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F30/00—Computer-aided design [CAD]
  • G06F30/30—Circuit design
  • G06F30/32—Circuit design at the digital level
  • G06F30/33—Design verification, e.g. functional simulation or model checking

Definitions

• the invention relates to the field of debugging integrated circuits, and more particularly to debugging integrated circuits using replicated logic.
• HDLs Hardware Description Languages
• a text representation of a circuit is compiled to generate a first register transfer level (RTL) netlist.
• the first RTL netlist may be mapped to a target architecture, such as a field programmable gate array (FPGA), to create a prototype board for debugging the circuit.
• FPGA field programmable gate array
• a designer may find a problem area in the circuit. The designer may select this portion of the circuit to replicate for further analysis. The selected portion of the circuit is replicated.
• Delay logic is inserted to delay inputs into the replicated portion of the circuit.
• Clock control logic may be inserted to allow the clock to the replicated portion of the circuit to be paused.
• the text representation of the circuit is recompiled to generate a second RTL netlist.
• the second RTL netlist may be mapped to a target architecture, such as a FPGA or an application specific integrated circuit (ASIC).
• ASIC application specific integrated circuit
• apparatuses are provided to carry out the above and other methods.
• Figure 1 illustrates a block diagram of a computer system that may be used to implement embodiments of the invention.
• Figure 2 is a flow chart illustrating an embodiment of a method of the invention.
• Figure 3 illustrates an example of a circuit section implementing an embodiment of the invention.
• Figure 4 illustrates an example of clock control logic according to an embodiment of the invention.
• Embodiments of a method and apparatus for debugging using replicated logic are described.
• numerous specific details are provided for a thorough understanding of embodiments of the invention.
• One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc.
• well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.
• FIG. 1 illustrates a block diagram of a computer system 100 that may be used to implement an embodiment of the invention.
• the computer system 100 includes a processor 102 coupled through a bus 110 to a random access memory (RAM) 104, a read-only memory (ROM) 106, and a mass storage device 108.
• RAM random access memory
• ROM read-only memory
• Mass storage device 108 represents a persistent data storage device, such a floppy disk drive, fixed disk drive (e.g. magnetic, optical, magneto-optical, or the like), or streaming tape drive.
• Processor 102 may be embodied in a general purpose processor, a special purpose processor, or a specifically programmed logic device.
• Display device 112 is coupled to processor 102 through bus 110 and provides graphical output for computer system 100.
• Keyboard 114 and cursor control unit 116 are coupled to bus 110 for communicating information and command selections to processor 102.
• I/O input/output
• Display device 112 is coupled to processor 102 through bus 110 and provides graphical output for computer system 100.
• Keyboard 114 and cursor control unit 116 are coupled to bus 110 for communicating information and command selections to processor 102.
• I/O input/output
• the content for implementing an embodiment of a method of the invention may be provided by any machine-readable media which can store data that is accessible by system 100, as part of or in addition to memory, including but not limited to cartridges, magnetic cassettes, flash memory cards, digital video disks, random access memories (RAMs), read-only memories (ROMs), and the like.
• the system 100 is equipped to communicate with such machine-readable media in a manner well- known in the art.
• the content for implementing an embodiment of the method of the invention may be provided to the system 100 from any external device capable of storing the content and communicating the content to the system 100.
• the system 100 may be connected to a network, and the content may be stored on any device in the network.
• FIG. 2 is a flow chart illustrating an embodiment of a method of the invention.
• a text representation of a circuit is compiled to generate a first register transfer (RTL) netlist.
• a circuit is typically described by a text representation by writing Hardware Description Language (HDL) source code descriptions of the elements of the circuit.
• HDL Hardware Description Language
• Writing HDL source code is well described in literature. See, for example, Verilog HDL: a Guide to Digital Design and Synthesis, Samir Palnithar, SunSoft Press, 1996; also see, A VHDL Synthesis Primer, J. Bhasher, Star Galaxy Publishing, 1996.
• the text representation is then input into a compiler.
• a compiler is a logic synthesis compiler, which is typically a computer program that operates on a general purpose computer system, although in some embodiments, the computer system may be a dedicated, special purpose computer system.
• An example of a logic synthesis compiler is the program "SynplifyTM" from Synplicity, Inc. of Sunnyvale, California.
• a RTL netlist is generated. The RTL netlist usually shows registers and other logic interconnected to show the flow of data through a circuit that was described in the text representation.
• the RTL netlist is mapped to a target architecture.
• the target architecture is typically determined by a supplier of the integrated circuit (IC). Examples of target architectures include field programmable gate arrays (FPGAs) and complex programmable logic devices from vendors such as Altera, Lucent Technologies, Advanced Micro Devices (AMD), and Lattice Semiconductor.
• FPGAs field programmable gate arrays
• AMD Advanced Micro Devices
• Lattice Semiconductor The mapping operation converts the RTL level description of the desired circuit into the equivalent circuit implemented using building blocks of the target architecture.
• a technology specific , netlist is generated. Conventional place and route software tools may then be used to create a design of circuitry in the target architecture.
• IC designers may build prototype boards using multiple ICs such as FPGAs to verify their designs. For example, after the compilation, mapping, and place and route operations, the circuit may be programmed into FPGAs to create a prototype of the design. The FPGAs can then be tested to determine any problem areas in the design.
• FPGAs field-programmable gate arrays
• the designer may select that portion of the circuit to replicate to further analyze the problem.
• a portion of the circuit is selected.
• the selected portion of the circuit is replicated. This replication may include a replication of the logic elements, the input signals, and the output signals of the selected portion of the circuit.
• clock signals are also replicated.
• Clock control logic is inserted to control the clock signals.
• the clock control logic allows the clock to the replicated logic block to be paused to stop the replicated logic from executing when certain conditions are present and to allow for single-stepping through the replicated logic to analyze an error.
• the designer may select a breakpoint to pause the clock to the replicated portion of the circuit when certain conditions are present. For example, the designer may choose values for the outputs or inputs that will pause the clock. This allows the designer to analyze the selected logic more carefully when certain problem conditions are present.
• delay logic is inserted to delay inputs into the replicated portion of the circuit.
• the length of the delay may be selected by the circuit designer.
• the delay logic allows an error observed in the selected portion of the circuit to be analyzed after the error is seen to occur since the error will reappear in the replicated portion of the circuit at a later time.
• the text representation of the circuit is recompiled to generate a second RTL netlist.
• the mapping and place and route operations may be performed using the second RTL netlist to implement the circuit in a target architecture, such as a FPGA.
• a synthesis operation is performed to generate an application specific integrated circuit (ASIC) from the second RTL netlist.
• a circuit with replicated logic is produced that allows a circuit designer to analyze a problem area in the design.
• Figure 3 illustrates an example of a section of a circuit 300 implementing an embodiment of the invention.
• Logic block 302 is a portion of the circuit in the original IC design. Debug of the original IC design revealed a problem with logic block 302. Therefore, original logic block 302 was selected and replicated to enable further analysis of the problem.
• the original logic block 302 is replicated to produce a replicated logic block 304.
• Outputs 308 from the original logic block 302 are replicated to produce replicated outputs 310. Inputs 306 may also be replicated.
• Delay logic 312 is inserted to delay inputs 306 into replicated logic block 304.
• the delay logic includes typical circuit logic and elements, such as inverters, that cause the inputs 306 to arrive at the replicated logic block 304 later in time than the inputs 306 will arrive at the original logic block 302. In this way, an error can be analyzed after the error is seen to occur in the original logic block, since the error will appear in the replicated logic block at a later time.
• Clock control logic 314 is inserted to control the clock signals 322 to the replicated logic block 304.
• the clock control logic 314 contains typical logic and circuit elements that allow the clock 322 to the replicated logic block 304 to be paused to stop the replicated logic from executing when certain conditions are present.
• the clock control logic 314 may also allow. for single stepping through the replicated logic on a clock by clock basis to analyze an error.
• a breakpoint 318 may be set to pause the clock when certain conditions are present.
• Figure 4 illustrates an example of the clock control logic 314 according to an embodiment of the invention.
• the system clock 316 that clocks the circuit flows through the latch 400 and acts as the clock 322 to the replicated logic block 304.
• the breakpoint 318 switches the clock 322 to a latched version of the system clock 316, which can be controlled by clock control signals 320 in order to allow the clock 322 to be paused and single-stepped on a cycle by cycle basis.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• General Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Theoretical Computer Science (AREA)
• Evolutionary Computation (AREA)
• Geometry (AREA)
• Design And Manufacture Of Integrated Circuits (AREA)
• Logic Circuits (AREA)
• Tests Of Electronic Circuits (AREA)
• Test And Diagnosis Of Digital Computers (AREA)
• Hardware Redundancy (AREA)
• Debugging And Monitoring (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (2)

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• 2002
  • 2002-08-09 US US10/215,869 patent/US6904576B2/en not_active Expired - Lifetime
• 2003
  • 2003-08-05 WO PCT/US2003/024601 patent/WO2004015596A2/en not_active Ceased
  • 2003-08-05 AU AU2003261401A patent/AU2003261401A1/en not_active Abandoned
  • 2003-08-05 DE DE60314530T patent/DE60314530T2/de not_active Expired - Lifetime
  • 2003-08-05 JP JP2004527782A patent/JP4806529B2/ja not_active Expired - Lifetime
  • 2003-08-05 EP EP03784944A patent/EP1546947B1/en not_active Expired - Lifetime
  • 2003-08-05 AT AT03784944T patent/ATE365349T1/de not_active IP Right Cessation
• 2008
  • 2008-07-01 US US12/166,298 patent/US7962869B2/en not_active Expired - Lifetime

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