Centralized built-in soft-repair architecture for integrated circuits with embedded memories

Abstract

A large-scale integrated circuit with built-in self-repair (BISR) circuitry for enabling redundancy repair for embedded memories in each of a plurality of processor cores with embedded built-in self-test (BIST) circuitry. The BISR circuitry receives and decodes BIST data from the embedded memories into fail signature data in a physical-aware form on which repair analysis can be performed. The fail signature data is reformatted into a unified repair format, such that a fuse encoder circuit can be used to encode fuse patterns in that unified repair format for a repair entity for each of the embedded memories. The fuse patterns are reconfigured into the appropriate order for storing in shadow fuse registers associated with the specific embedded memories.

Claims

1. An integrated circuit, comprising: a first processor core, comprising: logic circuitry; a plurality of embedded memories, each associated with at least one repair entity; and built-in self-test circuitry; and built-in self-repair circuitry, comprising: a first decode function, having an input coupled to the first processor core, for decoding test data from each of the embedded memories into fail signature data in a physical-aware format for the associated memory; align and merge circuitry, for reformatting the fail signature data from the first decode function into a unified repair format for all of the plurality of embedded memories of the first processor core; one or more fuse encoders, having an input coupled to the align and merge circuitry, each for generating a fuse pattern in the unified repair format for a repair entity; fuse reconfiguration logic, for reconfiguring the fuse patterns generated by the one or more fuse encoders from the unified repair format into a fuse pattern having an order corresponding to one or more of the repair entities for a selected one of the plurality of embedded memories; and a plurality of shadow fuse registers, each having an input coupled to the fuse reconfiguration logic, each for storing a fuse pattern for the repair entities of an associated embedded memory.

2. The integrated circuit of claim 1, wherein the unified repair format for the first processor core includes a plurality of portions numbering at least the maximum number of repair entities among the plurality of embedded memories of the first processor core, each portion including a plurality of bit positions numbering at least the maximum number of bits of the fail signature data in the physical-aware format for the corresponding repair entity among the plurality of embedded memories of the first processor core.

3. The integrated circuit of claim 2, wherein the align and merge circuitry comprises: a plurality of alignment functions, each associated with one of the plurality of embedded memories, for splitting the physical-aware fail signature data into a plurality of portions corresponding to the unified repair format; for each of the plurality of alignment functions, a plurality of register stages, each register stage corresponding to one of the portions of the unified repair format, and storing the corresponding portion of the physical-aware fail signature data; and merge circuitry, for merging the contents of one register stage for each of the plurality of embedded memories for application to a corresponding fuse encoder.

4. The integrated circuit of claim 3, wherein the plurality of alignment functions each pad excess bit positions in the portions of physical-aware fail signature data beyond that required for enabling the corresponding repair entity for its associated memory.

5. The integrated circuit of claim 1, wherein the first decode function comprises: comparison circuitry for comparing the test data from each of the embedded memories with expected data for that memory to produce fail signature data; and a plurality of multiplexer mapping circuits, each associated with one of the plurality of embedded memories, each for mapping the fail signature data for the associated memory into the physical aware format for that memory.

6. The integrated circuit of claim 5, wherein the comparison circuitry produces the fail signature for each of the embedded memories at a common output; and further comprising: a plurality of decode circuits, each associated with one of the plurality of embedded memories, having an input coupled to the common output of the comparison circuitry and an input receiving an indicator that the current fail signature data corresponds to its embedded memory, for communicating the fail signature data to the multiplexer mapping circuit associated with its embedded memory responsive to the indicator indicating that the fail signature data corresponds to its embedded memory.

7. The integrated circuit of claim 1, wherein the first decode function comprises: a plurality of decode circuits, each associated with one of the plurality of embedded memories, having an input coupled to the first processor core and an input receiving an indicator that the current test data corresponds to its embedded memory, and having an output; a plurality of multiplexer mapping circuits, each associated with one of the plurality of embedded memories and having an input coupled to the output of a corresponding decode circuit, each multiplexer mapping circuit for mapping the test data for the associated memory into the physical-aware format for that memory; and a plurality of comparison circuits, each for comparing the test data from one of the embedded memories as received from a corresponding multiplexer mapping circuit with expected data for that memory to produce fail signature data for that memory.

8. The integrated circuit of claim 1, further comprising: a second processor core, comprising: logic circuitry; a plurality of embedded memories, each associated with at least one repair entity; and built-in self-test circuitry; and wherein the built-in self-repair circuitry further comprises: a second decode function, having an input coupled to the first processor core, for decoding test data from each of the embedded memories into fail signature data in a physical-aware format for the associated memory; wherein the align and merge circuitry is also for reformatting the fail signature data from the second decode function into the unified repair format; and wherein the unified repair format including a plurality of portions numbering at least the maximum number of repair entities among the plurality of embedded memories of the first and second processor cores, each portion including a plurality of bit positions numbering at least the maximum number of bits of the fail signature data in the physical-aware format for the corresponding repair entity among the plurality of embedded memories of the first and second processor cores.

9. The integrated circuit of claim 1, further comprising: a fuse non-volatile read-only-memory, for storing fuse pattern data for each of the repair entities for each of the embedded memories; and a fuse controller, for writing contents of the shadow fuse register for one or more of the embedded memories into corresponding locations of the fuse non-volatile read-only-memory.

10. The integrated circuit of claim 1, further comprising: circuitry for communicating the fuse pattern data stored in at least one of the shadow fuse registers to its associated embedded memory.

11. A method of executing built-in self-repair functionality in an integrated circuit, comprising: executing a built-in self-test routine within a first processor core of the integrated circuit, the first processor core comprising a plurality of embedded memories, each memory associated with at least one repair entity; communicating test data from the built-in self-test routine for one of the plurality of embedded memories to built-in self-repair circuitry in the integrated circuit; decoding the test data into fail signature data in a physical-aware format for the embedded memory; reformatting the fail signature data into a unified repair format for the first processor core, the unified repair format including a plurality of portions numbering at least the maximum number of repair entities among the plurality of embedded memories of the first processor core, each portion including a plurality of bit positions numbering at least the maximum number of bits of the fail signature data in the physical-aware format for the corresponding repair entity among the plurality of embedded memories of the first processor core; encoding the fail signature in the unified repair format into a fuse pattern, in the unified repair format, for the repair entities of the embedded memory; reconfiguring the fuse pattern from the unified repair format into a fuse pattern having an order corresponding to the repair entities for the embedded memory; and then storing the reconfigured fuse pattern in one or more shadow fuse registers associated with the embedded memory.

12. The method of claim 11, wherein the reformatting step comprises: splitting the physical-aware fail signature data into a plurality of portions corresponding to the unified repair format; storing the corresponding portion of the physical-aware fail signature data in a plurality of register stages, each register stage corresponding to one of the portions of the unified repair format; and merging the contents of one register stage for each of the plurality of embedded memories for application to a corresponding fuse encoder.

13. The method of claim 12, wherein the reformatting step further comprises: padding excess bit positions in the portions of physical-aware fail signature data beyond that required for enabling the corresponding repair entity.

14. The method of claim 11, wherein the decoding step comprises: comparing the test data for the embedded memory with expected data for that memory to produce the fail signature data; and mapping the fail signature data for the embedded memory into the physical-aware format for that memory.

15. The method of claim 11, wherein the decoding step comprises: mapping the test data for the associated memory into the physical-aware format for that memory; and then comparing the test data from the embedded memory with expected data for that memory to produce the fail signature data.

16. The method of claim 11, further comprising: writing contents of the shadow fuse register for the embedded memory into a fuse non-volatile read-only-memory.

17. The method of claim 11, further comprising: storing contents of a shadow fuse register in a repair address register of its associated embedded memory.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is an electrical diagram, in block form, of a conventional built-in self-repair architecture in an integrated circuit.

(2) FIG. 2 is an electrical diagram, in block form, of a system-on-a-chip (SoC) integrated circuit device constructed according to embodiments.

(3) FIG. 3 is an electrical diagram, in block form, of an architecture for built-in self-repair circuitry as applied to multiple processor cores according to an embodiment.

(4) FIG. 4 is an electrical diagram, in block form, of built-in self-repair circuitry for one of the processor cores in the architecture of FIG. 3 according to an embodiment.

(5) FIG. 5 is an electrical diagram, in block form, of the decode memory physical map and align-and-merge circuitry in the built-in self-repair circuitry of FIG. 4 according to an embodiment.

(6) FIG. 6 is an electrical diagram, in block form, of fuse reconfiguration logic in the architecture of FIG. 5 according to that embodiment.

(7) FIGS. 7a through 7c are electrical diagrams, in block form, of the operation of the fuse reconfiguration logic of FIG. 6 as applied to each of three embedded memory architectures, according to that embodiment.

(8) FIG. 8 is an electrical diagram, in block form, of shadow fuse registers and associated logic circuitry in the architecture of FIG. 5 according to an embodiment.

(9) FIG. 9 is an electrical diagram, in block form, of the decode memory physical map and align-and-merge circuitry in the built-in self-repair circuitry of FIG. 4 according to another embodiment.

DETAILED DESCRIPTION OF THE INVENTION

(10) The one or more embodiments described in this specification are implemented into a multiple-core large-scale integrated circuit, such as that suitable as a system-on-a-chip (SoC) or similar device, as it is contemplated that such implementation is particularly advantageous in that context. However, it is also contemplated that concepts of this invention may be beneficially applied to other applications, including general purpose microprocessors, application specific processors, and the like. Accordingly, it is to be understood that the following description is provided by way of example only, and is not intended to limit the true scope of this invention as claimed.

(11) FIG. 2 illustrates, in block diagram form, the generalized architecture of an example of SoC 400 constructed according to these embodiments. In this example, SoC 400 as shown in FIG. 2 follows the generalized architecture of a modern system-on-a-chip such as in the TDAxx and DRAx families of processors available from Texas Instruments Incorporated. Those skilled in the art having reference to this specification will recognize that SoC 400 may include additional or alternative functions beyond those shown in FIG. 2, or may have its functions arranged according to a different architecture from that shown in FIG. 2.

(12) SoC 400 includes multiple processor cores 430a, 430b, 430c, etc. that carry out various programmable arithmetic and logic functions as appropriate for the end application of SoC 400. Examples of the various types of processor cores 430 include generic programmable processors, digital signal processors (DSPs) or other application-specific or customized logic, fixed sequence generators, and the like. For purposes of this description, these processor cores 430 each constitute a block of programmable or custom logic circuitry in combination with embedded memory resources. As typical in the art, these processor cores 430 are portable in the sense that each can be placed, as a whole, in an integrated circuit layout for providing a particular desired function, and are reusable in the sense that the same processor core may be used in different overall SoC architectures. The particular form in which a given processor core 430x is defined can also vary; soft cores are in the form of synthesizable data according to a hardware description language or gate-level netlist, while hard cores are defined as a low-level physical description or actual integrated circuit layout. Processor cores 430 are also referred to in the art as intellectual property cores, IP cores, or more simply IPs, and are often distributed under license agreements with the owner of the intellectual property rights in the design. As described above in connection with the Background of the Invention, processor cores 430a, 430b, 430c in SoC 400 need not originate from the same source or vendor; rather, it is not uncommon for multiple processor cores, from different vendors and of different functional and BIST architectures, to reside within the same large scale integrated circuit.

(13) According to this embodiment, the embedded memory resources of processor cores 430a, 430b, 430c of SoC 400 may be realized as random access memory (RAM) for data storage, flash or other non-volatile memory for storage of data or program instructions, or a combination of these memory types. As discussed above, these embedded memory resources may not be directly accessible over the functional datapath (e.g., via system bus 415) but may be testable only by embedded BIST circuitry and communicated only via a corresponding BIST datapath of processor core 430.

(14) Other memory resources may also reside in SoC 400, for example as shown by non-volatile memory arrays 410a, 410b and RAM 411, each of which is accessible over system bus 415 or direct memory access (DMA) bus 417. While memory resources 410a, 410b, 411 are shown in FIG. 2 as unitary blocks, these memory resources may alternatively be realized as multiple memory blocks or arrays. Various memory cell types and arrangements may be used to implement these memory resources 410a, 410b, 411. For example, RAM 411 may be realized by static RAM (SRAM), dynamic RAM (DRAM), or the like, and non-volatile memories 410a, 410b may be realized as flash memory (as shown in FIG. 2), non-flash EEPROM memory, mask-programmable read-only memory (ROM), one-time-programmable (OTP) ROM, and the like. In addition, it is contemplated that individual instances of memory resources may have any one of a number of access architectures, including single-port and multi-port access for RAM 411.

(15) Various peripheral functions may also be provided in SoC 400. In the architecture of FIG. 2, these peripherals include analog-to-digital converter (ADC) cores 424, timers 426, and general purpose input/output (GPIO) interface 428, each of which is coupled to system bus 415 and DMA bus 417 so as to be accessible to processor cores 430a, 430b, 430c and to one another. Other peripherals such as serial interfaces, network interfaces, various signal processing functions, and the like may also be included in SoC 400. SoC 400 also includes other functions such as external memory interface 413, power and clock circuitry, and other conventional support functions as known in the art.

(16) In a more general sense, it is contemplated that the various memory resources and other functions in the architecture of SoC 400 may not be physically realized in the arrangement shown in FIG. 2, but may instead be placed at various locations within the integrated circuit. In this regard, multiple instances of those memory resources and other functions may in fact be physically (and logically, for that matter) distributed throughout SoC 400. These and other variations in the arrangement of SoC 400 that will be apparent to those skilled in the art having reference to this specification are contemplated to be within the scope of this disclosure.

(17) According to these embodiments, SoC 400 includes built-in self-repair (BISR) circuitry 450 and fuse ROM 452. As shown in FIG. 2, BISR circuitry 450 is coupled to processor cores 430a, 430b, 430c via BIST datapaths BISTa, BISTb, BISTc, respectively. These BIST datapaths BISTa, BISTb, BISTc correspond to the conventional BIST interfaces over which processor cores 430a, 430b, 430c respectively export BIST data to BIST or other test circuitry. In these embodiments, BISR circuitry 450 receives data over these BIST datapaths resulting from the execution of self-test program routines as carried out by and within processor cores 430a, 430b, 430c themselves, for example upon power-up of SoC 400.

(18) In addition, conventional BIST circuitry 454 may be provided in SoC 400, as shown in FIG. 2. BIST circuitry 454 is provided to initiate and evaluate self-test routines for circuitry outside of those functions that include their own embedded BIST function (i.e., other than processor cores 430a, 430b, 430c in this example), typically at power-up of SoC 400. BISR circuitry 450 according to these embodiments may also receive data corresponding to the contents of non-embedded SoC memories 410a, 410b, 411, such data including, for example, the results of routines executed by BIST circuitry 454 or test algorithms applied by external automated test equipment. Additionally or in the alternative, it is contemplated that BISR circuitry 450 may have an external interface so as to receive commands and expected data from automated test equipment (not shown), and to communicate test results in response.

(19) According to these embodiments, BISR circuitry 450 is constructed to include a unified repair architecture for performing repair analysis for embedded memories, and perhaps also non-embedded memories in SoC 400, despite the architectural diversity among those memories. As will become apparent from the following description, this unified architecture is enabled by the aligning and merging the fail signature data from these diverse memory architectures into an interface that is applied to the unified repair architecture. Repair analysis, as performed under the unified repair architecture on the aligned and merged fail signature data, results in repair data that are reconfigured and encoded for storing in shadow fuses for each of the diverse memories.

(20) Referring now to FIG. 3, the datapath architecture of SoC 400 including BISR circuitry 450 according to these embodiments will be described. As shown in this FIG. 3, BISR circuitry 450 interfaces with the embedded BIST datapath of each of processor cores 430 (shown as processor cores 430a through 430x in FIG. 3) on its input side. According to these embodiments, decode functions 20a through 20x of BISR circuitry 450 decode the data presented by processor cores 430a through 430x into fail signature data that is arranged for application to unified test and repair datapath 30. As will be described in further detail below, these decoded fail signature data are physical-aware, in that the data are aligned and merged into a physical format for the corresponding embedded memories, as appropriate for repair analysis. Unified test and repair datapath 30 also interfaces to the non-embedded memories 410, 411, if desired. The decoded fail signature data are then applied by unified test and repair datapath 30 to centralized BIRA circuitry 40. Because of the unified physical-aware arrangement of the fail signature data as applied by datapath 30, centralized BIRA circuitry 40 is operable to analyze and encode the fail signature for embedded (and non-embedded) memories of diverse architectures and banking into repair data applicable to each individual repairable memory. If desired, fuse controller 451 can receive these repair data and program non-volatile fuses in fuse ROM 452 to permanently enable the redundancy repair. Alternatively, soft repair may be implemented by retaining the repair data for each memory in shadow fuses, such as banks of flip-flops for each repairable memory, within BISR circuitry 450.

(21) FIG. 4 illustrates the functional architecture of BISR circuitry 450 according to these embodiments. In this arrangement, decode functions 20a through 20x in the datapath architecture shown in FIG. 3 include exclusive-OR functions 22a through 22x and decode memory physical map functions 24a through 24x as shown in FIG. 4. The BIST datapath of each of processor cores 430a through 430x is coupled to an input of a corresponding bit-wise exclusive-OR function 22a through 22x, respectively, for comparison of the contents of the one of the embedded memories under test with the corresponding expected data for that test, for example as presented by the BIST circuitry of the corresponding processor core 430, or by BIST circuitry 454. The outputs of exclusive-OR functions 22a through 22x present the fail signature for the particular memory under test in each processor core 430a through 430x, on a common data bus for all of the embedded memories. These fail signature data are applied to a corresponding decode memory physical map function 24a through 24x.

(22) Decode memory physical map functions 24a through 24x decode the fail signature data provided at the common output of the corresponding exclusive-OR function 22a through 22x according to which embedded memory is under test, to separately present per-memory fail signature data. Decode memory physical map functions 24a through 24x also decode that fail signature data from a form according to the logical address architecture for the particular embedded memory, to a physical-aware form upon which repair analysis can be performed for each memory. In other words, the per-memory physical-aware fail signature data presented by functions 24a through 24x present those data according to a physical view corresponding to the physical repair architecture of the particular embedded memory. For example, decode memory physical map function 24a presents three separate outputs M.sub.1.sub._q, M.sub.2.sub._q, M.sub.3.sub._q, respectively corresponding to embedded memories M.sub.1, M.sub.2, M.sub.3 of processor core 430a. These separate outputs from decode memory physical map function 24a reflect that the logical-to-physical mapping and fail signature decoding may differ among the various embedded memories in a given processor core 430. For example, if embedded memory M.sub.1 has only redundant columns, the fail signature data on output M.sub.1.sub._q will include only the column fail signature; if, for example, embedded memory M.sub.2 has redundant rows and columns, its fail signature data on output M.sub.2.sub._q will include both row and column fail signatures. As such, the functional architecture of BISR circuitry 450 according to these embodiments can efficiently comprehend these differences in physical, logical, and repair architectures, even among embedded memories within black box processor cores.

(23) The BISR architecture of these embodiments is also capable of analyzing and repairing non-embedded memories, such as memories 410a, 410b, 411 in SoC 400 of FIG. 2. Because these memories can be directly controlled, for example by BIST circuitry 454, no decoding of a general purpose datapath is necessary. As such, the outputs of non-embedded memories 410a, 410b, 411 are applied to an input of corresponding exclusive-OR functions 23a, 23b, 23c for comparison with expected data for those memories, for example as provided by BIST circuitry 454. The resulting fail signature is provided by exclusive-OR functions 23a, 23b, 23c to physical map logic functions 25a, 25b, 25c, respectively, which map the fail signature from its logical architecture to a physical-aware mapping, on which repair analysis can be performed.

(24) In the functional architecture shown in FIG. 4, align and merge function 32 receives the per-memory physical-aware fail data from decode functions 24a through 24x for the embedded memories under test, as well as the physical-aware fail data from physical map logic functions 25a through 25c for non-embedded memories 410a, 410b, 411, and aligns and merges these data into a unified format for purposes of repair analysis. As such, align and merge function 32 provides the functional circuitry for arranging the per-memory fail signature data from diverse embedded (and perhaps non-embedded) memories into test and repair datapath 30 of FIG. 3, for applying to the unified repair architecture of BIRA function 40 according to these embodiments.

(25) As shown in FIG. 4, repair analysis and fuse encode circuitry 42 of BIRA function 40 receives the fail signature data for the one or more memories under test from align and merge function 32. Because that fail signature data in a unified format regardless of the architecture of the memories themselves, repair analysis and fuse encode repair analysis and fuse encode function 42 can essentially be shared across multiple memories and across multiple processor cores 430a through 430x, according to these embodiments. As will be described below, function 42 will operate to derive and encode a fuse pattern for the applicable repair entities for each of the memories under test, from the fail signature data for that memory.

(26) The fuse patterns derived by repair analysis and fuse encode function 42 are in the unified repair format, rather than arranged according to the particular architecture of the memories. Accordingly, fuse and shadow chain reconfiguration logic 44 is provided to reconfigure the fuse patterns derived by repair analysis and fuse encode function 42 into the proper order for enabling the desired repair entities for the rows or columns to be replaced in the memories under test. Function 42 then applies the reconfigured fuse pattern to the appropriate shadow fuse registers 46 for the memory under test. As shown in FIG. 4, each of the embedded and non-embedded memories has its own shadow fuse register 46. According to these embodiment, the contents of shadow fuse registers 46 can be scanned out in shift register manner for application to the respective embedded memories of processor cores 430 (e.g., written to registers in those memories that store the row or column addresses to be replaced) to accomplish soft repair in the conventional manner. In this case, soft-repair circuitry, such as conventional clock and control circuitry (not shown), will be provided to control the scanning out of the fuse pattern data from shadow fuse registers 46 to the corresponding embedded memories in the conventional manner. Alternatively or in addition, the contents of shadow fuse registers 46 can be scanned out to fuse controller 451 for programming into FuseROM 452 to accomplish hard repair in the conventional manner.

(27) FIG. 5 shows the construction of a portion of BISR circuitry 450 associated with processor core 430a and its embedded memories M.sub.1, M.sub.2, M.sub.3, according to an embodiment. It is contemplated that the portion of BISR circuitry 450 shown in FIG. 5 and described herein will be representative of similar circuitry in BISR circuitry 450 associated with other processor cores 430; in addition, it is contemplated that a portion of BISR circuitry 450 may be shared among multiple processor cores 430.

(28) As shown in both FIGS. 4 and 5, the BIST datapath from processor core 430a is applied to an input of exclusive-OR function 22a, which receives corresponding expected data as generated by embedded BIST circuitry within processor core 430a, or from external circuitry such as BIST circuitry 454 or external automated test equipment. In some cases, the diverse architecture among embedded memories M.sub.1, M.sub.2, M.sub.3 may be reflected in differing logical bit widths for the data read from those memories. As such, exclusive-OR function 22a in this embodiment is constructed to have sufficient data width to process the widest possible data word. In this example, memory M.sub.3 provides the widest logical word width lw3 among embedded memories M.sub.1, M.sub.2, M.sub.3, and as such the bus width from processor core 430 a to exclusive-OR function 22a, as well as the data width of the output of exclusive-OR function 22a itself, are at least at this logical word width lw3.

(29) As described above, exclusive-OR function 22a performs a bit-wise comparison of the memory output communicated from the one of the embedded memories M.sub.1, M.sub.2, M.sub.3 of processor core 430 a under test, with the expected data for corresponding addresses of that memory as generated by the applicable test circuitry, to provide a fail signature indicating which bits of the output data, if any, fail the test by not matching the corresponding bits of expected data. According to this architecture, the fail signature presented by exclusive-OR function 22a at any given time may come from any one of the embedded memories M.sub.1, M.sub.2, M.sub.3 of processor core 430a. As such, decode memory physical map function 24a is provided to decode the fail signature according to which of memories M.sub.1, M.sub.2, M.sub.3 it belongs. In this example, decode memory physical map function 24a carries out this decoding by bit-wise AND functions 52.sub.1 through 52.sub.3. Each bit of AND functions 52.sub.1 through 52.sub.3 receives a corresponding fail signature bit at one input, and an identifier (M1, M2, M3, respectively) indicating which of the embedded memories M.sub.1, M.sub.2, M.sub.3 is currently being accessed. Accordingly, only the one of AND functions 52.sub.1 through 52.sub.3 that is associated with the memory currently under test will pass its fail signature data through to the remainder of the repair analysis. According to this embodiment, the bit width of AND functions 52.sub.1 through 52.sub.3 may thus vary according to the logical word width of its corresponding memory M.sub.1, M.sub.2, M.sub.3, respectively, to save chip area. As shown in FIG. 5, AND function 55.sub.1 has a logical width lw1 corresponding to that of memory M.sub.1, AND function 55.sub.2 has a logical width lw2 corresponding to that of memory M.sub.2, AND function 55.sub.3 has the widest logical width lw3, corresponding to that of memory M.sub.3.

(30) While AND functions 52.sub.1 through 52.sub.3 decode the fail signature data from exclusive-OR function 22a according to the currently accessed memory, multiplexer mapping functions 54.sub.1, 54.sub.2, 54.sub.3 of memory decode physical map function 22a map the fail signature data from the logical architecture of embedded memories M.sub.1, M.sub.2, M.sub.3 to a physical view corresponding to the physical repair architecture of the particular embedded memory, on which the repair analysis can be performed. It is contemplated that those skilled in the art having reference to this specification can implement the particular arrangement of multiplexer mapping functions 54.sub.1, 54.sub.2, 54.sub.3 appropriate for the specific architectures of the embedded memories, in the conventional manner. The resulting physical-aware fail signature data produced by multiplexer mapping functions 54.sub.1, 54.sub.2, 54.sub.3 are provided to align and merge function 32, at physical word widths w1, w2, w3, respectively.

(31) According to these embodiments, align and merge function 32 transforms the physical-aware fail signature data from decode memory physical map function 24a into a unified repair format on which centralized repair analysis and fuse encoding are performed by BIRA circuitry 40. In the particular architecture shown in FIG. 5, align and merge function 32 accomplishes this alignment and merging by splitting the fail signature data from decode memory physical map function 24a at boundaries between repair entities, and placing those data within a unified repair format. The unified repair format is arranged according to a super-set of the repair entities over the associated embedded memories for this processor core, such that the format is sufficient to encode a fuse pattern for the memory with the most complex repair architecture (i.e., largest number of repair entities, and longest corresponding fuse signature). Additional bits of the unified repair format are padded (e.g., with 0) for those memories having less complex repair architectures (i.e., fewer repair entities, or shorter fuse signatures).

(32) The architecture of FIG. 5 will be described for an example in which embedded memory M.sub.1 of processor core 430a has one repair entity (e.g., a redundant column as indicated by its column repair address (CRA) register), and embedded memories M.sub.2 and M.sub.3 have two available repair entities (e.g., each with a redundant column as indicated by its CRA register, and a redundant row as indicated by its row repair address (RRA) register), with physical word width w3 being wider than physical word width w2. As such, the unified repair format in this example will contemplate two repair entities, with the width of the fail signature data being at least as large as physical word width w3. In this embodiment, align and merge function 32 is constructed to include alignment function 56.sub.x for each memory, that splits the fail signature data from function 24a into portions corresponding to the number of available repair entities for its memory M.sub.x, and register stages 60 that receive the split portions of fail signature data and apply it to the appropriate centralized fuse encoders 64. In this example, since memory M.sub.1 has only one repair entity, alignment function 56.sub.1 does not split the fail signature data from function 24a, but applies it to register stage 60b.sub.1 for its repair entity, padding any excess bit positions of register stage 60b.sub.1 and the entirety of register stage 60a.sub.1 with 0 data. Alignment function 56.sub.2 splits the fail signature data for memory M.sub.2 from multiplexed mapping function 54.sub.2 into two portions at the repair entity boundary (e.g., the midpoint of the fail signature data), and applies one portion to register stage 60a.sub.2 for one of the repair entities and the other portion to register stage 60b.sub.2 for the other repair entity; any excess bit positions of register stages 60a.sub.2, 60b.sub.2 are filled with 0 data. The fail signature data for memory M.sub.3 are also center-decoded, such that alignment function 56.sub.3 applies one portion of the fail signature data from multiplexer mapping function 54.sub.3 to register stage 60a.sub.3 for one of the repair entities, and applies the other portion to register stage 60b.sub.3 for the other repair entity, padding any excess bit positions with 0 data. In this example, because the upper portion of the fail signature data for memory M.sub.3 is associated with the lower repair entity and register stage 60b.sub.3 and the lower portion of the fail signature data is associated with the upper repair entity and register stage 60a.sub.3, align and merge function 24 swaps the position of these fail signature data portions as shown in FIG. 5.

(33) The aligned decoded fail signature data are then merged by OR functions 62a, 62b for application to the available repair entities. In this example, OR function 62a receives the contents of upper register stages 60a.sub.1, 60a.sub.2, 60a.sub.3, one of which will typically include fail signature data from the memory under test and the others of which will include 0 data in this example, and will forward that data to fuse encoder 64a. Conversely, OR function 62b receives the contents of lower register stages 60b.sub.1, 60b.sub.2, 60b.sub.3, only one of which will typically include fail signature data at any given time, and will forward that data to fuse encoder 64b.

(34) According to this embodiment, BIRA circuitry 40 includes one or more fuse encoders 64, each of which can be used for any one of the embedded memories of a given processor core 430. The number of fuse encoders 64 corresponds to the maximum number of repair entities for an embedded memory in that processor core 430. For the example of FIG. 5, the maximum number of repair entities among embedded memories M.sub.1, M.sub.2, M.sub.3 of processor core 430a is two (i.e., for memories M.sub.2, M.sub.3). As such, two fuse encoders 64a, 64b are provided in this instance of BIRA circuitry 40 for processor core 430a.

(35) Each fuse encoder 64a, 64b is constructed of logic circuitry arranged in the conventional manner for encoding fail signature data for a memory into a fuse pattern that enables one of the repair entities for that memory. For example, if the two repair entities for a memory are redundant columns, the fail signature data will indicate the column address in which a read failure occurs, and thus the column address for which a redundant column is to be included in the function of the memory. However, because the fail signature data presented to fuse encoders 64a, 64b are arranged in a unified repair format, fuse encoders 64a, 64b are each capable of encoding the fuse pattern for each of multiple embedded memories, regardless of the particular architectures of those memories.

(36) In the architecture of FIG. 5, fuse encoders 64a, 64b present the encoded fuse patterns for the corresponding repair entities to fuse reconfiguration logic 44. Fuse reconfiguration logic 44 reconfigures the fuse patterns from the unified repair format into the arrangement applicable to the memory to which the fuse pattern pertains.

(37) In this embodiment, fuse reconfiguration logic 44 is constructed as a series of latches associated with each fuse encoder 64, in combination with multiplexers that selectively route data stored in those latches according to an identifier of the memory currently under test. The number of latches in each series corresponds to the number of bit positions in the unified repair format, which is defined by the maximum number of bits of the fuse pattern for an associated repair entity, as will be evident from an example of fuse reconfiguration logic 44 shown in FIG. 6 for the case of processor core 430a described above, which includes three embedded memories M.sub.1, M.sub.2, M.sub.3.

(38) In this example, embedded memory M.sub.1 has one repair entity for which the fuse pattern consists of six bits, embedded memory M.sub.2 has two repair entities with fuse patterns of two bits each, and embedded memory M.sub.3 has two repair entities with fuse patterns of four bits each. The unified repair architecture for processor core 430a as implemented by BIRA circuitry 40 must be capable of producing a fuse pattern sufficient for all of embedded memories M.sub.1, M.sub.2, M.sub.3. Accordingly, given this repair architecture, the unified repair architecture for processor core 430a requires two fuse encoders 64a, 64b (for the maximum number of repair entities of two), one generating a fuse pattern of six bits and the other generating a fuse pattern of four bits. As mentioned above, for those memories for which the fuse pattern is smaller than that allowed by the unified repair format, align and merge function 32 and fuse encoders 64 will pad the excess bit positions with 0 data (or other don't care values) as placeholders in those bit positions. One may tabulate the unified repair format as utilized by these embedded memories M.sub.1, M.sub.2, M.sub.3 as follows:

(39) TABLE-US-00001 Unified Repair Format for Processor Core 430a Lower Fuse Encoder Upper Fuse Encoder M.sub.1 D D D D D D 0 0 0 0 M.sub.2 D D 0 0 0 0 D D 0 0 M.sub.3 D D D D 0 0 D D D D
where D indicates that the fuse pattern for that memory will include a data bit, and where 0 in the table indicates an excess bit position that is padded with the 0 (i.e., don't care) value for that memory. The example of fuse reconfiguration logic 44 shown in FIG. 6 implements this encoding of the fuse patterns within that unified repair format, with two series of latches for the two fuse encoders 64a, 64b of BIRA circuitry 40. One series of six latches 70.sub.0 through 70.sub.5 receives a fuse pattern from lower fuse encoder 64b, and the other series of four latches 72.sub.0 through 72.sub.3 receives a fuse pattern from upper fuse encode 64a. These latches 70, 72 are connected in series, such that upon the application of a series of clock pulses to the latch clock inputs (the clock lines not shown in FIG. 6), their contents are shifted in sequence and serially read out at serial output FDO. In this embodiment, dummy data are shifted into the series of latches at latch 70.sub.0 at line FDI (e.g., line FDI may be hard-wired to a logic level). More specifically, each of latches 70.sub.0 through 70.sub.5 receives a corresponding data bit of the fuse pattern from lower fuse encoder 64b at a D input, and each of latches 72.sub.0 through 72.sub.3 receives a corresponding data bit of the fuse pattern from upper fuse encoder 64a at its D input. Each of latches 70, 72 also has a serial input SI, an output Q, and a clock input. In this example, the SI input of latch 70.sub.0 receives an external value on line FDI, and the Q outputs of latches 70.sub.0 through 70.sub.4 are connected directly to the SI input of the next latch 70.sub.1 through 70.sub.5, respectively, in that series. Similarly, the Q output of each of latches 72.sub.0 through 72.sub.2 is connected to the SI input of the corresponding next latch 72.sub.1 through 72.sub.4, respectively.

(40) Multiplexers 73a through 73d in fuse reconfiguration logic 44 implement the serial communication of fuse pattern data for each of the embedded memories M.sub.1, M.sub.2, M.sub.3, as will now be described. In this example, multiplexer 73a receives the Q output of latch 70.sub.1 at its 0 (or false) input, the Q output of latch 70.sub.3 at its 1 (or true) input, and an indicator that memory M.sub.3 is selected at its control input. Multiplexer 73b receives the output of multiplexer 73a at its 0 input, the Q output of latch 70.sub.5 at its 1 input, and an indicator that memory M.sub.1 is selected at its control input. Multiplexer 73c receives the output of multiplexer 73b at its 0 input, the Q output of latch 72.sub.1 at its 1 input, and an indicator that memory M.sub.2 is selected at its control input. Multiplexer 73d receives the output of multiplexer 73c at its 0 input, the Q output of latch 72.sub.3 at its 1 input, and the indicator that memory M.sub.3 is selected at its control input. It is contemplated that the indicators of which memory is selected will be generated by the applicable BIST embedded circuitry, or other internal or external test circuitry, to identify which memory is currently under test. As a result, the fuse pattern data in the unified repair format, as generated by upper and lower fuse encoders 64a, 64b, are loaded in parallel into the latches 70, 72 of fuse reconfiguration logic 44, and are serially clocked out on line FDO in a format that corresponds to the shadow fuse register 46 (FIG. 4) for the current embedded memory under test.

(41) FIGS. 7a through 7c illustrate the operation of fuse reconfiguration logic 44 for the selections of embedded memories M.sub.1, M.sub.2, M.sub.3, respectively. FIG. 7a illustrates the data path for the case in which memory M.sub.1 is the memory under test, such that the fuse pattern consists of six bits for a single repair entity. As described above relative to FIG. 5, merge and align function 32 applied the fail signature data only to lower register stage 60b.sub.1, with upper register stage 60a.sub.1 being padded with 0 data values. As such, only lower fuse encoder 64b is operating on actual fail signature data when memory M.sub.1 is the memory under test, and only latches 70.sub.0 through 70.sub.5 associated with lower fuse encoder 64b will receive valid encoded fuse pattern data, as indicated by the bold highlighting in FIG. 7a. The data loaded into latches 72.sub.0 through 72.sub.3 from upper fuse encoder 64a will be ignored, as indicated by the dashed representation. In other words, multiplexers 73b, 73c, 73d will route the fuse pattern data from latches 70.sub.0 through 70.sub.5 to output FDO, bypassing latches 72.sub.0 through 72.sub.3. In operation, therefore, the encoded fuse pattern data from lower fuse encoder 64b are loaded, in parallel, into latches 70.sub.0 through 70.sub.5; the padded 0 values from upper fuse encoder 64a are also loaded into latches 72.sub.0 through 72.sub.3 at the same time. A sequence of clock pulses (not shown) are then applied to latches 70, 72, causing the contents of latches 70.sub.0 through 70.sub.5 to be shifted out from output FDO in reverse order, for application to the shadow fuse register 46 associated with memory M.sub.1.

(42) For the case in which memory M.sub.2 is the memory under test, multiplexers 73 of fuse reconfiguration logic 44 will route the fuse pattern data in the manner shown in FIG. 7b. Two repair entities are available for memory M.sub.2, as described above, and as such fuse pattern data encoded by both of upper and lower fuse encoders 64a, 64b (two bits for each) are to be forwarded to the corresponding shadow fuse register 46. Accordingly, as shown in FIG. 7b for this case, multiplexers 73a and 73b operate to route the Q output of latch 70.sub.1 to the SI input of latch 72.sub.0, bypassing latches 70.sub.2 through 70.sub.5; similarly, multiplexers 73c and 73d route the Q output of latch 72.sub.1 to output FDO, bypassing latches 72.sub.2 and 72.sub.3. Accordingly, after the parallel loading of fuse pattern data from fuse encoders 64a, 64b into latches 70.sub.0, 70.sub.1, 72.sub.0, 72.sub.1 (and loading the padded 0 values into the other latches), these four bits of fuse pattern data are then serially read out at output FDO by the application of four clock pulses to latches 70, 72.

(43) FIG. 7c similarly shows the routing of fuse pattern data in fuse reconfiguration logic 44 for the case of memory M.sub.3 as the memory under test. As described above, memory M.sub.3 has two repair entities, each enabled by a four-bit fuse pattern. In this example, multiplexers 73a and 73b operate to route the Q output of latch 70.sub.3 to the SI input of latch 72.sub.0, bypassing latches 70.sub.4 and 70.sub.5, and multiplexer 73d routes the Q output of latch 72.sub.3 to output FDO. In operation, the fuse pattern data from fuse encoders 64a, 64b are loaded in parallel into latches 70.sub.0 through 70.sub.3 and 72.sub.0 through 72.sub.3 (with padded 0 values loaded into latches 70.sub.4 and 70.sub.5), and are serially read out from output FDO by the application of eight clock pulses to latches 70, 72.

(44) FIG. 8 illustrates the architecture of shadow fuse registers 46 for the example described above relative to FIGS. 6 and 7a through 7c, according to an embodiment. In this example, the output FDO from fuse reconfiguration logic 44 is applied in parallel to shadow fuse registers 46.sub.1, 46.sub.2, 46.sub.3 for memories M.sub.1, M.sub.2, M.sub.3, respectively, of processor core 430a. Shadow fuse registers 46.sub.1, 46.sub.2, 46.sub.3 are selectively enabled by clock signals CLK_M1, CLK_M2, CLK_M3, respectively, as issued by corresponding clock gates 82.sub.1, 82.sub.2, 82.sub.3, such that only the shadow fuse register 46 for the current memory under test receives updated fuse pattern data from fuse reconfiguration logic 44, while the other shadow fuse registers 46 retain their previous contents. In this embodiment, clock leaker function 80 receives clock signals CLK/M1, CLK/M2, and CLK/M3 as applied to memories M.sub.1, M.sub.2, M.sub.3, respectively, and combines these clock signals into a single clock signal CLK_ALL that is applied to an input of each of clock gates 82.sub.1, 82.sub.2, 82.sub.3. Another input of clock gate 82.sub.1 receives indicator signal M1 corresponding to memory M.sub.1 being selected; similarly, clock gates 82.sub.2 and 82.sub.3 receive signals M.sub.2, M.sub.3, respectively, indicating selection of their respective embedded memories M.sub.2, M.sub.3. As such, the one of clock gates 82.sub.1, 82.sub.2, 82.sub.3 receiving a positive indicator that its memory is the currently selected memory under test will pass clock signal CLK_ALL as its output clock signal CLK_M1, CLK_M2, CLK_M3, allowing its corresponding shadow fuse register 46.sub.1, 46.sub.2, 46.sub.3 to receive the fuse pattern data that is serially presented at line FDO.

(45) Referring back to FIGS. 3 and 4, upon the storing of the fuse pattern in shadow fuse registers 46, those fuse pattern data can be communicated from shadow fuse registers 46 to the corresponding embedded memories within the various processor cores 430, as well as for the non-embedded memories 410a, 410b, 411 if desired. According to the embodiment of FIG. 5, for example, shadow fuse registers 46 are serially scanned out in the manner of a single shift register, under the control of scan clock circuitry 47, for storage of the fuse pattern data in the corresponding repair address registers of the associated embedded memories, as conventional in the art. Alternatively or in addition, the contents of shadow fuse registers 46 can be similarly scanned out to fuse controller 451, which in turn programs the corresponding hard repair fuses in FuseROM 452 with the redundancy repair information suitable for the corresponding memories. Typically, this hard repair operation will be performed at a manufacturing test, rather than as part of a BIST sequence on power-up. For those devices in which hybrid repair is performed, to the extent that additional repair entities are invoked during power-up BIST sequences due to additional failing cells occurring over the operating life of the device, those soft repair fuse patterns then stored in shadow fuse registers 46 may be scanned out to their corresponding embedded memories for repair over the duration of that power-on interval.

(46) FIG. 9 illustrates the construction of a portion of BISR circuitry 450 associated with processor core 430a and its embedded memories M.sub.1, M.sub.2, M.sub.3, according to an alternative embodiment from that described above relative to FIG. 5. As before, this portion of BISR circuitry 450 shown in FIG. 9 can be representative of similar circuitry in BISR circuitry 450 associated with other processor cores 430, but is not necessarily the same. For example, other processor cores 430 may be associated with BISR circuitry 450 in the form shown in FIG. 5.

(47) In the embodiment of FIG. 9, physical map decoding is performed on the data as received from the memory under test, rather than on the fail signature following comparison with the expected data. As such, the functional datapath from processor core 430a is applied directly to decode memory physical map function 24a for the three memories M.sub.1, M.sub.2, M.sub.3, rather than to an exclusive-OR function for comparison with the expected data from BIST circuitry 454. The logical bit width of the functional datapath from processor core 430a is at least as wide as the widest logical bit width of the three memories, which in this case is the logical bit width lw3 of memory M.sub.3. AND functions 52.sub.1 through 52.sub.3 of decode memory physical map function 24a receive the data from the datapath of processor core 430a at one input, and an identifier (M1, M2, M3, respectively) indicating which of the embedded memories M.sub.1, M.sub.2, M.sub.3 is currently being accessed. Accordingly, only the one of AND functions 52.sub.1, 52.sub.2, 52.sub.3 that is associated with the memory under test will pass its memory data forward to its corresponding multiplexer mapping function 54.sub.1, 54.sub.2, 54.sub.3, which will in turn map the memory data from the logical architecture of its embedded memory M.sub.1, M.sub.2, M.sub.3 to a physical architecture on which the repair analysis can be performed, according to a physical view corresponding to the physical repair architecture of the particular embedded memory.

(48) According to this embodiment, multiplexer mapping functions 54.sub.1, 54.sub.2, 54.sub.3 thus present the memory data from their respective memories M.sub.1, M.sub.2, M.sub.3, in a physical-aware form, to an input of a corresponding exclusive-OR function 22a1, 22a2, 22a3, respectively. Each of exclusive-OR functions 22a1, 22a2, 22a3 also receive, at another input, the expected data as generated by BIST circuitry 454 or external automated test equipment for the particular test being performed. These expected data are similarly arranged in a physical-aware form, matching that of the expected data presented by decode memory physical map function 24a for the intended one of memories M.sub.1, M.sub.2, M.sub.3, so that the proper comparison may be made. The provision of dedicated exclusive-OR functions 22a1, 22a2, 22a3 for each memory M.sub.1, M.sub.2, M.sub.3 allows these functions to have a bit width matching that of its memory, rather than a bit width corresponding to the widest bit width among the memories. The exclusive-OR function 22a1, 22a2, 22a3 associated with the memory currently under test will thus generate fail signature data indicating the bit positions at which the decoded and mapped memory data from decode memory physical map function 24a do not match the expected data for that test. These fail signature data for embedded memories M.sub.1, M.sub.2, M.sub.3 are then presented to align and merge function 32, which transforms the physical-aware fail signature data into a unified repair format upon which centralized repair analysis and fuse encoding is applied by BIRA circuitry 40, as described above relative to FIGS. 5, 6, and 7a through 7c.

(49) These embodiments provide important advantages relative to conventional BISR circuitry, particularly in large-scale integrated circuits such as SoC devices. As discussed above, conventional BISR circuitry provides a dedicated fuse encoder for each embedded memory in each processor core, because of differences in the repair architectures among those various memories. According to these embodiments, however, the same fuse encoder circuitry can be used for multiple embedded memories of varying repair architectures, regardless of whether the embedded memories are directly accessible or are embedded within a black box processor core that has its own embedded BIST circuitry datapath. By reducing the number of instances of fuse encoders required in the integrated circuit, these embodiments can save substantial chip area relative to conventional BISR implementations, for example by as much as 50% over state-of-the-art EDA self-repair solutions for processor cores with embedded BIST. In addition, it is contemplated that these embodiments can save substantial memory repair test time and power consumption, as compared with conventional large-scale integrated circuit architectures in which black box processor cores with embedded BIST cannot take advantage of built-in repair techniques.

(50) While one or more embodiments have been described in this specification, it is of course contemplated that modifications of, and alternatives to, these embodiments, such modifications and alternatives capable of obtaining one or more the advantages and benefits of this invention, will be apparent to those of ordinary skill in the art having reference to this specification and its drawings. It is contemplated that such modifications and alternatives are within the scope of this invention as subsequently claimed herein.