FIELD OF THE INVENTION

[0001] The present disclosure relates generally to the field of electronic device testing systems and more specifically to the field of electronic device testing equipment for testing devices under test (DUTs).

BACKGROUND OF THE INVENTION

[0002] Automated test equipment (ATE) can be any testing assembly that performs a test on a semiconductor device or electronic assembly. ATE assemblies may be used to execute automated tests that quickly perform measurements and generate test results that can then be analyzed. An ATE assembly may be anything from a computer system coupled to a meter, to a complicated automated test assembly that may include a custom, dedicated computer control system and many different test instruments that are capable of automatically testing electronics parts and/or semiconductor wafer testing, such as system-on-chip (SOC) testing or integrated circuit testing. ATE systems both reduce the amount of time spent on testing devices to ensure that the device functions as designed and serve as a diagnostic tool to determine the presence of faulty components within a given device before it reaches the consumer.

[0003] FIG. 1 is a schematic block diagram of a conventional automatic test equipment body 100 for testing certain typical DUTs e.g. a semiconductor memory device such as a DRAM. The ATE includes an ATE body 100 with hardware bus adapter sockets 11 OA- 110N. Hardware bus adapter cards 11 OA- 110N specific to a particular communication protocol e.g. PCIe, USB, SAS SATA etc. connect to the hardware bus adapter sockets provided on the ATE body and interface with the DUTs via cables specific to the respective protocol. The ATE body 100 also includes a tester processor 101 with an associated memory 108 to control the hardware components built into the ATE body 100 and to generate the commands and data necessary to communicate with the DUTs being tested through the hardware bus adapter cards. The tester processor 101 communicates with the hardware bus adapter cards over system bus 130. The tester process may be programmed to include certain functional blocks including an algorithmic pattern generator 102 and a comparator 106. Alternatively, the algorithmic pattern generator 102 and comparator 106 may be hardware components mounted on an expansion or adapter card that plug into the ATE body 100.

[0004] The ATE body 100 tests the electrical functions of the DUTs 112 A- 112N connected to the ATE body 100 through hardware bus adapters plugged into the hardware bus adapter sockets of the ATE body 100. Accordingly, the tester processor 101 is programmed to communicate the test programs needed to be run to the DUTs using the protocol unique to the hardware bus adapters. Meanwhile, the other hardware components built into the ATE body 100 communicate signals with each other and with the DUTs according to test programs operating in the tester processor 101.

[0005] The test program run by the tester processor 101 may include a function test which involves writing input signals created by the algorithmic pattern generator 102 to the DUTs, reading out the written signals from the DUTs and using the comparator 106 to compare the output with the expected patterns. If the output does not match the input, the tester processor 101 will identify the DUT as being defective. For example, if the DUT is a memory device such as a DRAM, the test program will write data generated by the algorithmic pattern generator 102 to the DUT using a Write Operation, read data from the DRAM using a Read Operation and compare the expected bit pattern with the read pattern using the comparator 106.

[0006] In conventional systems, the tester processor 101 has the functional logic blocks to generate the commands and test patterns used in testing the DUTs, such as the algorithmic pattern generator 102 and the comparator 106, programmed in software directly on the processor. However, in some instances certain functional blocks such as the comparator 106 may be implemented on a field programmable gate array (FPGA), which is an application specific integrated circuit (ASIC) type semiconductor device that can program logic circuits according to a user's demand. [0007] The FPGAs used in conventional systems rely on the tester processor 101 to transfer the commands and test patterns to the FPGA, which the FPGA in turn relays over to the DUTs. Because the tester processor is responsible for generating the commands and test patterns, the number of DUTs that can be tested with a given ATE body is limited by the processing capabilities of the tester processor. Where the tester processor generates all the commands and test patterns, bandwidth constraints on the system bus 130 connecting the tester processor to the various hardware components, including any FPGA devices and hardware bus adapter sockets, also places an upper limit on the number of DUTs that can tested simultaneously.

[0008] Also, in conventional systems, the communication protocol used to communicate with the DUTs is fixed because the hardware bus adapter cards that plug into the ATE body 100 are single purpose devices that are designed to communicate in only one protocol and cannot be reprogrammed to communicate in a different protocol. For example, an ATE body configured to test PCIe devices will have hardware bus adapter cards plugged into the body that support only the PCIe protocol. In order to test DUTs supporting a different protocol, the user would ordinarily need to replace the PCIe hardware bus adapter cards with bus adapter cards supporting the other protocol. Unless the PCIe hardware bus adapter cards are physically substituted with cards supporting the other protocol, such a system can only test DUTs that support the PCIe protocol. Thus, on the test floor, critical time is consumed replacing hardware bus adapter cards when DUTs running a different protocol from the one that the existing adapter cards support need to be tested.

BRIEF SUMMARY OF THE INVENTION

[0009] Accordingly, a need exists for a tester architecture that can address the problems with the systems described above. What is needed is a test architecture whereby the command and test pattern generation functionality can be transferred onto the FPGA, so that the processing load on the tester processor and the bandwidth requirements on the system bus can be kept at a minimum. This would then allow more DUTs to be tested simultaneously than in prior configurations where the tester processor bore the entire processing load and the system bus conveyed test data and commands for all the DUTs connected to the ATE body.

[0010] Further, what is needed is a test architecture whereby the communicative protocol engine can be programmed on FPGA devices so that the protocol used to communicate with the DUTs is reconfigurable. This would eliminate the need for single purpose hardware bus adapter cards because the protocol engine would reside in programmable logic blocks on the FPGA devices rather than in hardware on a bus adapter card.

[0011] Using the beneficial aspects of the systems described, without their respective limitations, embodiments of the present invention provide a novel solution to address these problems.

[0012] In one embodiment, a tester system for testing a plurality of DUTs is provided, which comprises a system controller for controlling a test program, wherein the system controller is coupled to a bus. The tester system further comprises a plurality of modules also coupled to the bus, where each module is operable to test a plurality of DUTs. Each of the modules comprises a tester processor coupled to the bus and a plurality of configurable blocks communicatively coupled to the tester processor. Each of the configurable blocks is operable to communicate with an associated DUT and further operable to be programmed with a communication protocol for communicating test data to and from said associated device under test.

[0013] In another embodiment, an ATE apparatus is provided, which comprises a system controller communicatively coupled to a tester processor, wherein the system controller is operable to transmit instructions for performing an automated test to the tester processor. The apparatus further comprises a plurality of FPGA components coupled to the tester processor, wherein each of said plurality of FPGA components is programmed to comprise at least one reconfigurable circuit for implementing one of a plurality of communication protocols. The apparatus also comprises at least one communication port for communicating with a DUT, wherein the plurality of FPGA components is operable to write test data to a plurality of DUTs and operable to read test data from the plurality of DUTs in accordance with the instructions from the system controller using one of the plurality of communication protocols.

[0014] In one embodiment, a method for testing using an ATE is provided, wherein said method comprises transmitting instructions for performing an automated test from a system controller to a tester processor. The method further comprises programming at least one reconfigurable circuit for implementing one of a plurality of communication protocols onto each of a plurality of FPGA components coupled to the tester processor. Further, the method comprises writing test data to a plurality of DUTs from the plurality of FPGA components using the one of a plurality of communication protocols and, subsequently, reading test data from the plurality of DUTs to the plurality of FPGA components using the one of a plurality of communication protocols, wherein both the writing and the reading is conducted in accordance with the instructions from the system controller.

[0015] In one aspect of the invention, the communication protocol is reconfigurable and is programmed directly onto the FPGAs eliminating the need for hardware bus adapter cards. While the tester processor communicates with the FPGAs on the system bus in the same protocol that its been initially programmed with e.g. PCIe, the FPGAs can be configured to communicate with the DUTs in any protocol that the DUTs support. As a result, one ATE body can be easily configured to test many kinds of DUTs. In one embodiment, new protocols can be downloaded and installed directly on the FPGAs via a simple software download without any kind of hardware interactions. For example, the FPGAs in the ATE body can be configured with the PCIe protocol to test PCIe devices for part of the day and subsequently reconfigured via a software download to test SATA devices for the remainder of the day. Also, if a new protocol is released, the FPGAs can easily be configured with that protocol via a software download instead of having to physically switch all the hardware bus adapter cards in the system. Finally, if a non-standard protocol needs to be implemented for which there are no off-the-shelf adapter cards, the FPGAs can nonetheless be configured to implement such a protocol.

[0016] In another embodiment, the FPGAs can be configured to run more than one communicative protocol, wherein these protocols also can be downloaded and configured through software. This allows the tester hardware to test DUTs supporting different protocols simultaneously. For example, if an FPGA is configured to run both PCIe and SATA protocols, it can be connected to test a DUT that supports both PCIe and SATA protocols. Alternatively, it can be connected to test two different DUTs, one DUT supporting the PCIe protocol and the other DUT supporting the SATA protocol.

[0017] The following detailed description together with the accompanying drawings will provide a better understanding of the nature and advantages of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements.

[0019] FIG.1 is a schematic block diagram of a conventional automatic test equipment body for testing a typical device under test (DUT);

[0020] FIG. 2 is a high level schematic block diagram of the interconnections between the system controller, the site modules and the DUTs according to one embodiment of the present invention;

[0021] FIG. 3 is a detailed schematic block diagram of the site module and its interconnections with the system controller and the DUTs according to an embodiment of the present invention; [0022] FIG. 4 is a detailed schematic block diagram of the instantiated FPGA tester block of FIG. 2 according to an embodiment of the present invention;

[0023] FIG. 5 is a high level flowchart of an exemplary method of testing DUTs according to an embodiment of the present invention;

[0024] FIG. 6 is a continuation of FIG. 5 and is a flowchart of an exemplary method of testing DUTs in the bypass mode in one embodiment of the present invention;

[0025] FIG. 7 is a continuation of FIG. 5 and is a flow chart of an exemplary method of testing DUTs in the hardware accelerator pattern generator mode in one embodiment of the present invention;

[0026] FIG. 8 is a continuation of FIG. 5 and is a flow chart of an exemplary method of testing DUTs in the hardware accelerator memory mode in one embodiment of the present invention;

[0027] FIG. 9 is a continuation of FIG. 5 and is a flow chart of an exemplary method of testing DUTs in the hardware accelerator packet builder mode in one embodiment of the present invention;

[0028] FIGS. 10A is a block diagram representation of an exemplary packet built in accordance with the method from FIG. 6 in one embodiment of the present invention;

[0029] FIGS. 10B is a block diagram representation of an exemplary packet built in accordance with the method from FIG. 7 in one embodiment of the present invention;

[0030] FIGS. IOC is a block diagram representation of an exemplary packet built in accordance with the method from FIG. 8 in one embodiment of the present invention;

[0031] FIGS. 10D is a block diagram representation of an exemplary packet built in accordance with the method from FIG. 9 in one embodiment of the present invention. [0032] In the figures, elements having the same designation have the same or similar function.

DETAILED DESCRIPTION OF THE INVENTION

[0033] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. While the embodiments will be described in conjunction with the drawings, it will be understood that they are not intended to limit the embodiments. On the contrary, the embodiments are intended to cover alternatives, modifications and equivalents. Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a thorough understanding. However, it will be recognized by one of ordinary skill in the art that the embodiments may be practiced without these specific details. In other instances, well- known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the embodiments.

NOTATION AND NOMENCLATURE SECTION

[0034] Some regions of the detailed descriptions which follow are presented in terms of procedures, logic blocks, processing and other symbolic representations of operations on data bits within a computer memory. These descriptions and

representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. In the present application, a procedure, logic block, process, or the like, is conceived to be a self- consistent sequence of steps or instructions leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, although not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated in a computer system.

[0035] It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the present invention, discussions utilizing the terms such as "aborting," "accepting," "accessing," "adding," "adjusting," "analyzing," "applying," "assembling," "assigning," "balancing,"

"blocking," "calculating," "capturing," "combining," "comparing," "collecting," "creating," "debugging," "defining," "depicting," "detecting," "determining,"

"displaying," "establishing," "executing," "flipping," "generating," "grouping," "hiding," "identifying," "initiating," "interacting," "modifying," "monitoring,"

"moving," "outputting," "performing," "placing," "presenting," "processing,"

"programming," "querying," "removing," "repeating," "resuming," "sampling," "simulating," "sorting," "storing," "subtracting," "suspending," "tracking,"

"transforming," "unblocking," "using," or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.

[0036] The description below provides a discussion of computers and other devices that may include one or more modules. As used herein, the term "module" or "block" may be understood to refer to software, firmware, hardware, and/or various

combinations thereof. It is noted that the blocks and modules are exemplary. The blocks or modules may be combined, integrated, separated, and/or duplicated to support various applications. Also, a function described herein as being performed at a particular module or block may be performed at one or more other modules or blocks and/or by one or more other devices instead of or in addition to the function performed at the described particular module or block. Further, the modules or blocks may be implemented across multiple devices and/or other components local or remote to one another. Additionally, the modules or blocks may be moved from one device and added to another device, and/or may be included in both devices. Any software

implementations of the present invention may be tangibly embodied in one or more storage media, such as, for example, a memory device, a floppy disk, a compact disk (CD), a digital versatile disk (DVD), or other devices that may store computer code.

[0037] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention. As used throughout this disclosure, the singular forms "a," "an," and "the" include plural reference unless the context clearly dictates otherwise. Thus, for example, a reference to "a module" includes a plurality of such modules, as well as a single module, and equivalents thereof known to those skilled in the art.

A TESTER WITH MIXED PROTOCOL ENGINE IN A FPGA BLOCK

[0038] Test throughput can be usually be improved in a number of ways. One way to decrease the testing time of DUTs is by transferring functionality formerly performed in software on a general-purpose tester processor to hardware accelerators implemented on FPGA devices. Another way is by increasing the number and types of devices under test (DUTs) that can be tested under prevailing hardware and time constraints, for example, by configuring the hardware so that DUTs supporting many different types of protocols can be tested with the same hardware without needing to replace or substitute any hardware components. Embodiments of the present invention are directed to so improving test efficiency in the hardware of the automatic test equipment.

[0039] FIG. 2 is an exemplary high level block diagram of the automatic test equipment (ATE) apparatus 200 in which a tester processor is connected to the devices under test (DUTs) through FPGA devices with built-in functional modules in accordance with an embodiment of the present invention. In one embodiment, ATE apparatus 200 may be implemented within any testing system capable of testing multiple DUTs simultaneously.

[0040] Referring to FIG. 2, an ATE apparatus 200 for testing semiconductor devices more efficiently in accordance with an embodiment of the present invention includes a system controller 201, a network switch 202 connecting the system controller to the site module boards 230A-230N, FPGA devices 211A-211M comprising instantiated FPGA tester blocks 210A-210N, memory block modules 240A-240M wherein each of the memory blocks is connected to one of the FPGA devices 211A-211M, and the devices under test (DUTs) 220A-220N, wherein each device under test 220A-220N is connected to one of the instantiated FPGA tester blocks 210A-210N.

[0041] In one embodiment, the system controller 201 may be a computer system, e.g., a personal computer (PC) that provides a user interface for the user of the ATE to load the test programs and run tests for the DUTs connected to the ATE 200. The Verigy Stylus™ Operating System is one example of test software normally used during device testing. It provides the user with a graphical user interface from which to configure and control the tests. It can also comprise functionality to control the test flow, control the status of the test program, determine which test program is running, and log test results and other data related to test flow. In one embodiment, the system controller can be connected to and control as many as 512 DUTs.

[0042] In one embodiment, the system controller 201 can be connected to the site module boards 230A-230N through a network switch, such as an Ethernet switch. In other embodiments, the network switch may be compatible with a different protocol such as Fibre Channel, 802.11 or ATM, for instance.

[0043] In one embodiment, each of the site module boards 230A-230N may be a separate standalone board used for purposes of evaluation and development that attaches to custom-built load board fixtures, on which the DUTs 220A-220N are loaded, and also to the system controller 201 from where the test programs are received. In other embodiments, the site module boards may be implemented as plug-in expansion cards or as daughter boards that plug into the chassis of the system controller 201 directly.

[0044] The site module boards 230A-230N can each comprise at least one tester processor 204 and at least one FPGA device. The tester processor 204 and the FPGA devices 211A-211M on the site module board run the test methods for each test case in accordance with the test program instructions received from the system controller 201. In one embodiment the tester processor can be a commercially available Intel 8086 CPU or any other well-known processor. Further, the tester processor may be operating on the Ubuntu OS x64 operating system and running the Core Software, which allows it to communicate with the Stylus software running on the system controller, to run the test methods. The tester processor 204 controls the FPGA devices on the site module and the DUTs connected to the site module based on the test program received from the system controller.

[0045] The tester processor 204 is connected to and can communicate with the FPGA devices over bus 212. In one embodiment, tester processor 204 communicates with each of the FPGA devices 211 A-211M over a separate dedicated bus. In one embodiment, tester processor 204 can control the testing of the DUTs 220A-220N transparently through the FPGAs with minimal processing functionality allocated to the FPGA devices. In this embodiment, the data traffic capacity of bus 212 can be exhausted rapidly because all the commands and data generated by the tester processor need to be communicated over the bus to the FPGA devices. In other embodiments, the tester processor 204 can share the processing load by allocating functionality to control the testing of the DUTs to the FPGA devices. In these embodiments, the traffic over bus 212 is reduced because the FPGA devices can generate their own commands and data.

[0046] In one embodiment, each of the FPGA devices 211A-211M is connected to its own dedicated memory block 240A-240M. These memory blocks can, among other things, be utilized to store the test pattern data that is written out to the DUTs. In one embodiment, each of the FPGA devices can comprise two instantiated FPGA tester blocks 210A-210B with functional modules for performing functions including implementation of communicative protocol engines and hardware accelerators as described further herein. Memory blocks 240A-240 M can each contain one or more memory modules, wherein each memory module within the memory block can be dedicated to one or more of the instantiated FPGA tester blocks 210A-210B.

Accordingly, each of the instantiated FPGA tester blocks 210A-210B can be connected to its own dedicated memory module within memory block 240A. In another embodiment, instantiated FPGA tester blocks 21 OA and 21 OB can share one of the memory modules within memory block 240A.

[0047] Further, each of the DUTs 220A-220N in the system can be connected to a dedicated instantiated FPGA tester block 210A-210N in a "tester per DUT"

configuration, wherein each DUT gets its own tester block. This allows separate test execution for each DUT. The hardware resources in such a configuration are designed in a manner to support individual DUTs with minimal hardware sharing. This configuration also allows many DUTs to be tested in parallel, where each DUT can be connected to its own dedicated FPGA tester block and be running a different test program.

[0048] The architecture of the embodiment of the present invention depicted in FIG. 2 has several advantages. First, it eliminates the need for protocol-specific hardware bus adapter sockets and cards in the system because the communication protocol modules can be programmed directly on the instantiated FPGA tester blocks within the FPGA devices. The instantiated tester blocks can be configured to communicate with the DUTs in any protocols that the DUTs support. Accordingly, if DUTs with different protocol support need to be tested, they can be connected to the same system and the FPGAs can be reprogrammed with support for the associated protocols. As a result, one ATE body can be easily configured to test DUTs supporting many different types of protocols.

[0049] In one embodiment, new protocols can be downloaded and installed directly on the FPGAs via a simple bit-stream download from a cache on system controller 201 without any kind of hardware interactions. For example, the FPGAs 211A-211M in the ATE apparatus 200 can be configured with the PCIe protocol to test PCIe devices initially and subsequently reconfigured via a software download to test SAT A devices. Also, if a new protocol is released, the FPGAs can easily be configured with that protocol via a bit-stream download instead of having to physically switch all the hardware bus adapter cards in the system. Finally, if a non-standard protocol needs to be implemented, the FPGAs can nonetheless be configured to implement such a protocol.

[0050] In another embodiment, the FPGAs 211A-211M can be configured to run more than one communicative protocol, wherein these protocols also can be

downloaded from system controller 201 and configured through software. For instance, instantiated FPGA tester block 21 OA can be configured to run the PCIe protocol while instantiated FPGA tester block 210B can be configured to run the SATA protocol. This allows the tester hardware to test DUTs supporting different protocols simultaneously. FPGA 211 A can now be connected to test a DUT that supports both PCIe and SATA protocols. Alternatively, it can be connected to test two different DUTs, one DUT supporting the PCIe protocol and the other DUT supporting the SATA protocol.

[0051] The other major advantage of the architecture presented in FIG. 2 is that it reduces processing load on the tester processor 204 by distributing the command and test pattern generating functionality to FPGA devices, where each DUT has a dedicated FPGA module running the test program specific to it. For instance, instantiated FPGA tester block 21 OA is connected to DUT 220A and runs test programs specific to DUT 220A. The hardware resources in such a configuration are designed in a manner to support individual DUTs with minimal hardware sharing. This "tester per DUT" configuration also allows more DUTs to be tested per processor and more DUTs to be tested in parallel. Furthermore, with the FPGAs capable of generating their own commands and test patterns in certain modes, the bandwidth requirements on bus 212 connecting the tester processor with the other hardware components, including FPGA devices, device power supplies (DPS) and DUTs, is also reduced. As a result more DUTs can be tested simultaneously than in prior configurations.

[0052] FIG. 3 provides a more detailed schematic block diagram of the site module and its interconnections with the system controller and the DUTs in accordance with an embodiment of the present invention. Referring to FIG. 3, the site modules of the ATE apparatus, in one embodiment, can be mechanically configured onto tester slices 340A- 340N, wherein each tester slice comprises at least one site module. In certain typical embodiments, each tester slice can comprise two site modules and two device power supply boards. Tester slice 340A of FIG. 3, for example, comprises site modules 310A and 310B and device power supply boards 332A and 332B. However, there is no limit to the number of device power supply boards or site modules that can be configured onto a tester slice. Tester slice 340 is connected to system controller 301 through network switch 302. System controller 301 and network switch 302 perform the same function as elements 201 and 202 in FIG. 2 respectively. Network switch 302 can be connected to each of the site modules with a 32 bit wide bus.

[0053] Each of the device power supply boards 332A-332B can be controlled from one of the site modules 310A-310B. The software running on the tester processor 304 can be configured to assign a device power supply to a particular site module. In one embodiment, the site modules 310A-310B and the device power supplies 332A-332B are configured to communicate with each other using a high speed serial protocol, e.g., Peripheral Component Interconnect Express (PCIe), Serial AT Attachment (SAT A) or Serial Attached SCSI (SAS), for instance.

[0054] In one embodiment, each site module is configured with two FPGAs as shown in FIG. 3. Each of the FPGAs 316 and 318 in the embodiment of FIG 3. is controlled by the tester processor 304 and performs a similar function to FPGAs 211A- 211M in FIG. 2. The tester processor 304 can communicate with each of the FPGAs using a 8 lane high speed serial protocol interface such as PCIe as indicated by system buses 330 and 332 in FIG. 3. In other embodiments, the tester processor 304 could also communicate with the FPGAs using different high speed serial protocols, e.g., Serial AT Attachment (SATA) or Serial Attached SCSI (SAS).

[0055] FPGAs 316 and 318 are connected to memory modules 308 and 304 respectively, where the memory modules perform a similar function to memory blocks 240A-240N in FIG. 2. The memory modules are coupled with and can be controlled by both the FPGA devices and the tester processor 304. [0056] FPGAs 316 and 318 can be connected to the DUTs 372A-372M on the load board 380 through buses 352 and 354 respectively. The load board 380 is a physical harness that allows a general purpose high speed connection at the site module end that is agnostic to the protocol used to communicate to the DUTs in on lines 352 and 354. At the DUT end, however, the load board needs to be designed so as to have connectors specific to the protocol being used by the DUT.

[0057] The DUTs 372A-372M, in one embodiment of the invention, are loaded on a load board 380 that is placed inside a thermal chamber 390 for testing. The DUTs 372A-372M and the load board 380 derive power from the device power supplies 332A and 332B.

[0058] The number of DUTs that can be connected to each FPGA is contingent on the number of transceivers in the FPGA and the number of I/O lanes required by each DUT. In one embodiment, FPGAs 316 and 318 can each comprise 32 high speed transceivers and buses 352 and 354 can each be 32 bits wide, however, more or less can be implemented depending on the application. If each DUT requires 8 I/O lanes, for example, only 4 DUTs can be connected to each FPGA in such a system.

[0059] FIG. 4 is a detailed schematic block diagram of an instantiated FPGA tester block of FIG. 2 according to an embodiment of the present invention.

[0060] Referring to FIG. 4, the instantiated FPGA tester block 410 is connected to the tester processor through PCIe upstream port 270 and to the DUT through PCIe downstream port 480.

[0061] Instantiated FPGA block 410 can comprise a protocol engine module 430, a logic block module 450, and a hardware accelerator block 440. The hardware accelerator block 440 can further comprise a memory control module 444, comparator module 446, a packet builder module 445, and an algorithmic pattern generator (APG) module 443. [0062] In one embodiment, logic block module 450 comprises decode logic to decode the commands from the tester processor, routing logic to route all the incoming commands and data from the tester processor 304 and the data generated by the FPGA devices to the appropriate modules, and arbitration logic to arbitrate between the various communication paths within instantiated FPGA tester block 410.

[0063] In one implementation, the communication protocol used to communicate between the tester processor and the DUTs can advantageously be reconfigurable. The communicative protocol engine in such an implementation is programmed directly into the protocol engine module 430 of instantiated FPGA tester block 410. The instantiated FPGA tester block 410 can therefore be configured to communicate with the DUTs in any protocol that the DUTs support. This advantageously eliminates the need for hardware bus adapter cards and no protocol-specific hardware need be replaced to test DUTs with different protocol support. In one embodiment, the protocols can be high speed serial protocols, including but not limited to SAT A, SAS or PCIe, etc. The new or modified protocols can be downloaded and installed directly on the FPGAs via a simple bit-stream download from the system controller through the tester processor without any kind of hardware interactions. Also, if a new protocol is released, the FPGAs can easily be configured with that protocol via a software download.

[0064] In FIG. 4, if the DUT coupled to the PCIe downstream port 480 is a PCIe device, a bit-file containing the instantiation of the PCIe protocol can be downloaded through the PCIe upstream port 470 and installed on the protocol engine module 430. Each FPGA device 316 or 318 can comprise one or more instantiated FPGA tester block and, consequently, one or more protocol engine modules. The number of protocol engine modules that any one FPGA device can support is limited only by the size and gate count of the FPGA.

[0065] In one embodiment of the present invention, each of the protocol engine modules within a FPGA device can be configured with a different communicative protocol. Accordingly, an FPGA device can be connected to test multiple DUTs, each supporting a different communicative protocol simultaneously. Alternatively, an FPGA device can be connected to a single DUT supporting multiple protocols and test all the modules running on the device simultaneously. For example, if an FPGA is configured to run both PCIe and SATA protocols, it can be connected to test a DUT that supports both PCIe and SATA protocols. Alternatively, it can be connected to test two different DUTs, one DUT supporting the PCIe protocol and the other DUT supporting the SATA protocol.

[0066] The hardware accelerator block 440 of FIG. 4 can be used to expedite certain functions on FPGA hardware than would be possible to do in software on the tester processor. The hardware accelerator block 440 can supply the initial test pattern data used in testing the DUTs. It can also contain functionality to generate certain commands used to control the testing of the DUTs. To generate test pattern data, accelerator block 440 uses the algorithmic pattern generator module 443.

[0067] The hardware accelerator block 440 can use comparator module 446 to compare the data being read from the DUTs to the data that was written to the DUTs in a prior cycle. The comparator module 446 comprises functionality to flag a mismatch to the tester processor 304 to identify devices that are not in compliance. More specifically, the comparator module 446 can comprise an error counter that keeps track of the mismatches and communicates them to the tester processor 304.

[0068] Hardware accelerator block 440 can connect to a local memory module 420. Memory module 420 performs a similar function to a memory module within any of the memory blocks 240A-240M. Memory module 420 can be controlled by both the hardware accelerator block 440 and the tester processor 304. The tester processor 304 can control the local memory module 420 and write the initial test pattern data to it.

[0069] The memory module 420 stores the test pattern data to be written to the DUTs and the hardware accelerator block 440 accesses it to compare the data stored to the data read from the DUTs after the write cycle. The local memory module 420 can also be used to log failures. The memory module would store a log file with a record of all the failures the DUTs experienced during testing. In one embodiment, the accelerator block 440 has a dedicated local memory module block 420 that is not accessible by any other instantiated FPGA tester blocks. In another embodiment, the local memory module block 420 is shared with a hardware accelerator block in another instantiated FPGA tester block.

[0070] Hardware accelerator block 440 can also comprise a memory control module

444. The memory control module 444 interacts with and controls read and write access to the memory module 420.

[0071] Finally, hardware accelerator block 440 comprises a packet builder module

445. The packet builder module is used by the hardware accelerator block in certain modes to construct packets to be written out to the DUTs comprising header/command data and test pattern data.

[0072] In certain embodiments, hardware accelerator block 440 can be programmed by the tester processor 304 to operate in one of several modes of hardware acceleration. In bypass mode, the hardware accelerator is bypassed and commands and test data are sent by the tester processor 304 directly to the DUT through path 472. In hardware accelerator pattern generator mode, test pattern data is generated by the APG module 443 while the commands are generated by the tester processor 304. The test packets are transmitted to the DUT through path 474. In hardware accelerator memory mode, the test pattern data is accessed from local memory module 420 while the commands are generated by the tester processor 304. The test pattern data is transmitted to the DUT through path 476. Routing logic 482 is needed to arbitrate between paths 472, 474 and 476 to control the flow of data to the DUT.

[0073] The site module can comprise a general purpose connector 481. Because the protocol engine module 430 can be configured to run any number of various communicative protocols, a general purpose high speed connector 481 is required on the site module. Accordingly, if the protocol implemented on the protocol engine module 430 needs to be changed, no accompanying physical modification needs to be made on the site module. The site module connects to the DUT using load board 380 that can connect to the general purpose connector on the site module end, but is specific to the protocol being implemented on the DUT end. DUTs supporting different

communicative protocols will require different configurations. Accordingly, the load board needs to be switched out and replaced if the protocol is reprogrammed to accommodate DUTs requiring a different configuration.

[0074] Figure 5 depicts a flowchart 500 of an exemplary process of testing DUTs according to an embodiment of the present invention. The invention, however, is not limited to the description provided by flowchart 500. Rather, it will be apparent to persons skilled in the relevant art(s) from the teachings provided herein that other functional flows are within the scope and spirit of the present invention.

[0075] Flowchart 500 will be described with continued reference to exemplary embodiments described above in reference to FIGS. 2, 3 and 4, though the method is not limited to those embodiments.

[0076] Referring now to FIG. 5, the user initiates setup and loads the test program into system controller at block 502. Initiating setup can comprise choosing one or more protocols from a library of available protocols to be configured onto the FPGA devices in the ATE apparatus 200. The protocols are cached as files on the system controller 301 and can be downloaded as bit files onto the FPGAs. The user can select the protocol from a list of releases available through a graphical user interface. Before a protocol is made available as an option, it has to be built, tested and integrated into a release. FPGA configurations that are released, among other things, contain definitions regarding the protocols supported and the number of transceivers available to connect DUTs. The library of releases can then be made available to a user through a graphical user interface.

[0077] At block 502, the user also loads the test program into the system controller 301 through the graphical user interface. The test program defines all the parameters of the test that needs to be run on the DUTs. At block 504, the system controller transmits instructions to the tester processor on the site module 310A. This step includes the transmission of the bit files for the protocol engines to be programmed onto the FPGAs. The system controller can comprise routing logic to route instructions for a particular test program to the tester processor connected to the DUT controlled by the test program.

[0078] At block 506, after receiving instructions from the system controller, the tester processor 304 can determine the hardware acceleration mode for running the tests on the DUTs connected to site module 310A.

[0079] In one embodiment, the tester processor 304 can operate in one of four different hardware acceleration modes. Each functional mode is configured to allocate functionality for generating commands and test data between the tester processor 304 and the FPGAs 316 and 318. In one embodiment, the tester processor can be programmed to operate in bypass mode, wherein all the commands and test data for testing the DUTs is generated by the tester processor 304 and the FPGAs 316 and 318 are bypassed.

[0080] In another embodiment, the tester processor 304 can be programmed to operate in hardware accelerator pattern generator mode, wherein pseudo-random data to be used in the testing of the DUTs is generated by the FPGAs 316 and 318 and the comparing is also done by the FPGAs, but the tester processor handles the command generation.

[0081] In yet another embodiment, the tester processor 304 can be programmed to operate in hardware accelerator memory mode, wherein the test pattern is pre-written onto the memory module connected to each FPGA 316 and 318 by the tester processor during initial set-up. The FPGAs in this mode access the dedicated memory device to retrieve the test data to be written to the DUTs, read the test data from the DUTs and compare the read data with the data written on the memory device. In this mode, each of the FPGAs controls the memory device in response to read and write operations from the DUTs. The tester processor, however, is still responsible for the command generation in this mode. [0082] In still another embodiment, the tester processor 304 can be programmed to operate in hardware accelerator packet builder mode, wherein the data and basic read/write/compare commands are generated by the FPGAs 316 and 318.

[0083] At block 508, the tester processor branches out to the mode under which the test will be run.

[0084] Figure 6 depicts a flowchart 600 of an exemplary process of testing DUTs in the bypass mode according to an embodiment of the present invention. The invention, however, is not limited to the description provided by flowchart 600. Rather, it will be apparent to persons skilled in the relevant art(s) from the teachings provided herein that other functional flows are within the scope and spirit of the present invention.

[0085] Flowchart 600 will be described with continued reference to exemplary embodiments described above in reference to FIGS. 2, 3 and 4, though the method is not limited to those embodiments.

[0086] Referring now to FIG. 6, in bypass mode, at block 602 the tester processor 304 generates commands and packet headers for the test packets to be routed to the DUTs. The tester process at block 604 also generates the test pattern data for the packets to be routed to the DUTs. In this mode there is no hardware acceleration because the tester processor generates its own commands and test data. FIG. 1 OA is a block diagram representation of a packet built in accordance with the method from FIG. 6 in one embodiment of the present invention.

[0087] At block 606, the tester processor communicates with instantiated FPGA block 410 and downstream port 480 to route the test packets containing the test pattern data to the DUTs. The bypass mode is a pass through mode, wherein, with some limited exceptions, the commands and data pass transparently through the instantiated FPGA block 410 directly to the DUTs. The DUTs are directly controlled by the tester processor 304 in bypass mode. While the instantiated FPGA block can comprise logic to route the packets through to the downstream port, it is not involved in either the command generation (also referred to as "signaling") or the data generation.

[0088] At block 608, the tester processor 304 communicates with downstream port 480 to initiate a read operation from the DUTs of the data that was previously written to the DUTs at block 606. At block 610, the tester processor compares the data read from the DUTs to the data written at block 606. If there is any mismatch between the data written at block 606 and the data read at block 610, a flag is sent by the tester processor 304 to the system controller 301 at block 612. The system controller will then flag the mismatch to the user.

[0089] In bypass mode, tester processor 304 is constrained in the number of DUTs it can support because its processing capabilities can be maximized quickly from generating all the commands and test data for the DUTs. Also, the number of DUTs that can be supported by site module 310A is further limited by the bandwidth constraints on system buses 330 and 332. In bypass mode, the bandwidth of buses 330 and 332 is exhausted relatively quickly because of the large volume of data that is transmitted by the tester processor 304 over to the DUTs. Thus, other modes with more hardware acceleration are made available, wherein the FPGA devices have more functionality to generate test data and commands.

[0090] Figure 7 depicts a flowchart 700 of an exemplary process of testing DUTs in the hardware accelerator pattern generator mode according to an embodiment of the present invention. The invention, however, is not limited to the description provided by flowchart 700. Rather, it will be apparent to persons skilled in the relevant art(s) from the teachings provided herein that other functional flows are within the scope and spirit of the present invention.

[0091] Flowchart 700 will be described with continued reference to exemplary embodiments described above in reference to FIGS. 2, 3 and 4, though the method is not limited to those embodiments. [0092] Referring now to FIG. 7, a method of hardware acceleration is shown wherein the FPGA devices share data generation functionality so as to relieve the processing load on the tester processor 304 and the data load on system buses 330 and 332. At block 702 of the hardware accelerator pattern generator mode, the tester processor 304 generates commands and packet headers for the packets to be routed to the DUTs. The tester process retains the functionality for signaling in this mode. The algorithmic pattern generator module 443 within the hardware accelerator block 440 generates the pseudo random test data to be written to the DUTs at block 704. The logic block module 450 comprises functionality for routing the data generated and adding it to the packets to be written out to the DUTs. FIG. 10B is a block diagram representation of a packet built in accordance with the method from FIG. 7 in one embodiment of the present invention.

[0093] The mode is considered "hardware accelerated" because the functionality for generating data can be done much faster in hardware by the algorithmic pattern generator of the FPGA device than in software by the tester processor. Also the "tester per DUT" architecture allows the DUT to be directly connected to its own dedicated instantiated FPGA tester block generating test pattern data for the DUT as shown in FIG. 4, which results in a substantial increase in bandwidth over the bypass mode where the tester processor 304 supplies all commands and data to the DUTs over system buses 330 and 332. With the FPGA devices sharing in the data generation functionality, the system buses 330 and 332 are freed up so commands can be communicated to the FPGAs at a faster rate than in the bypass mode. Further, for devices, such as solid state drives that require several iterations of testing, having a dedicated data path through the instantiated FPGA tester block speeds up testing considerably over one where the resources of the tester processor are shared by several DUTs. It also allows the DUT to operate at close to full performance because it does not have to wait for the tester processor to allocate processing resources to it.

[0094] In one embodiment, the algorithmic pattern generator module 443 can be programmed to generate data on the fly. The APG module can generate incremental patterns, pseudo-random patterns or some type of constant pattern. The APG module can also have certain gating capabilities to generate test patterns with stripes, diagonal stripes or alternating patterns. In one embodiment, the APG module can use finite state machines, counters or linear feedback shift registers, among other things, to generate test patterns. In some implementations, the APG module can be provided a starting seed as an initial value to generate more complex patterns.

[0095] At step 706, the instantiated FPGA block 410 communicates with the downstream port 480 to route the test pattern data to the DUTs in accordance with the commands and packet headers generated by the tester processor. The instantiated FPGA block 410, at step 708, communicates with the downstream port to read the test pattern data from the DUTs in accordance with commands generated by the tester processor. The comparator module 446 of the hardware accelerator block 440 is then used to compare the read data to the data written to the DUTs at block 710. The APG module 443 is designed in a way such that the comparator module can perform read operations on it with the same parameters that were used to generate the pseudo-random data and receive the same data that was written to the DUTs at block 704. The APG module 443 regenerates the data that was written to the DUTs on the fly and communicates it to the comparator module 446. Any mismatches are either logged on memory module 420 by the memory control module 444 or communicated by the instantiated FPGA block to the tester processor at block 712. The tester processor subsequently flags mismatches to the system controller at block 714 after receiving the error log.

[0096] Figure 8 depicts a flowchart 800 of an exemplary process of testing DUTs in the hardware accelerator memory mode according to an embodiment of the present invention. The invention, however, is not limited to the description provided by flowchart 800. Rather, it will be apparent to persons skilled in the relevant art(s) from the teachings provided herein that other functional flows are within the scope and spirit of the present invention. [0097] Flowchart 800 will be described with continued reference to exemplary embodiments described above in reference to FIGS. 2, 3 and 4, though the method is not limited to those embodiments.

[0098] Referring now to FIG. 8, a method of hardware acceleration is shown wherein the FPGA devices share data generation functionality so as to relieve the processing load on the tester processor 304 and the data load on system buses 330 and 332. As compared to the hardware accelerator pattern generator mode, in the hardware accelerator memory mode, the instantiated FPGA tester block accesses local memory module 420 for the data to be written to the DUTs instead of using the APG module 443.

[0099] At block 800 of the hardware accelerator pattern memory mode, the tester processor 304 generates commands and packet headers for the packets to be routed to the DUTs. The tester process retains the functionality for signaling in this mode. At block 802, the tester processor initializes the local memory module 420 of the instantiated FPGA tester block 410 with test patterns to be written out to the DUTs. One advantage of the hardware accelerator memory mode is that the test patterns generated by the tester processor may constitute real random data as opposed to pseudo-random data generated by the APG module 443 in the hardware accelerator pattern generator mode. Both the tester processor and the instantiated FPGA tester block have read and write access to the local memory module 420. However, the tester processor only accesses memory module 420 during initial set-up. During the accelerator mode, the tester processor does not access the memory module because the additional processing load on the tester processor 304 and the additional data load on the system buses 330 and 332 slows the acceleration down considerably.

[00100] At block 804, the instantiated FPGA tester block reads the test pattern data to be routed to the DUTs from the memory module 420. Because the memory module 420 is dedicated to the FPGA tester block or shared with just one other FPGA tester block, there is a high bandwidth connection between the two resulting in fast read operations. The logic block module 450 comprises functionality for routing the data generated and adding it to the packets to be written out to the DUTs. FIG. IOC is a block diagram representation of a packet built in accordance with the method from FIG. 8 in one embodiment of the present invention

[00101] After the data has been added to the packets, at block 806, the instantiated FPGA tester block communicates with the downstream port 480 to route the test pattern data to the DUTs in accordance with the commands and packet headers generated by the tester processor. The instantiated FPGA block 410, at step 808, communicates with the downstream port to read the test pattern data from the DUTs in accordance with commands generated by the tester processor. The comparator module 446 of the hardware accelerator block 440 is then used to compare the read data to the data written to the DUTs at block 810. Any mismatches are either logged on memory module 420 or communicated by the instantiated FPGA block to the tester processor at block 812. The tester processor subsequently flags mismatches to the system controller at block 814 after receiving the error log.

[00102] Figure 9 depicts a flowchart 900 of an exemplary process of testing DUTs in the hardware accelerator packet builder mode according to an embodiment of the present invention. The invention, however, is not limited to the description provided by flowchart 900. Rather, it will be apparent to persons skilled in the relevant art(s) from the teachings provided herein that other functional flows are within the scope and spirit of the present invention.

[00103] Flowchart 900 will be described with continued reference to exemplary embodiments described above in reference to FIGS. 2, 3 and 4, though the method is not limited to those embodiments

[00104] Referring now to FIG. 9, a method of hardware acceleration is shown wherein the FPGA devices share both data and command generation functionality so as to relieve the processing load on the tester processor 304 and the data load on system buses 330 and 332. This mode is also known as "full acceleration" mode because most of the control for running the device tests is shifted to the FPGA devices and the tester processor 304 retains control for only commands other than reads and writes and compares.

[00105] At block 902 of the hardware accelerator packet builder mode, the tester processor 304 generates commands to be communicated to the instantiated FPGA block 410 to generate its own packets. The tester processor retains functionality for only the non read/write/compare commands in this mode. The functionality for commands such as read, write and compare operations are conveyed to the instantiated FPGA blocks. At block 904, the packet builder module 445 of the instantiated FPGA tester block builds packets with header and command information to be communicated to the DUTs. The packets comprise at least the command type, the block address of the device and the test pattern data. FIG. 10D is a block diagram representation of a packet built in accordance with the method from FIG. 9 in one embodiment of the present invention.

[00106] The algorithmic pattern generator module 443 within the hardware accelerator block 440 generates the pseudo random test data to be written to the DUTs at block 906. The logic block module 450 comprises functionality for routing the data and commands generated by the instantiated FPGA block and consolidating them into packets to be written out to the DUTs.

[00107] At block 908, the instantiated FPGA tester block communicates with the downstream port 480 to route the test pattern data to the DUTs. The instantiated FPGA block 410, at step 910, communicates with the downstream port to read the test pattern data from the DUTs. The comparator module 446 of the hardware accelerator block 440 is then used to compare the read data to the data written to the DUTs at block 912. Any mismatches are either logged on memory module 420 or communicated by the instantiated FPGA block to the tester processor at block 914. The tester processor subsequently flags mismatches to the system controller at block 916 after receiving the error log.

[00108] The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as may be suited to the particular use contemplated.