Abstract: Disclosed herein is an improved logic module used for logic emulation along with an enhanced logic emulation board subject to logic verification. The logic module has a plurality of programmable LSIs capable of programming logic and a plurality of switching LSIs capable of programming connections, the LSIs being mounted on one or both sides of a board. Peripheral portions of the board carry connectors for electrical connection to the outside. There are two types of data lines: those directly coupling the connectors to the programmable LSIs, and those linking the connectors to the programmable LSIs via the switching LSIs. The programmable and switching LSIs constitute a crossbar connection arrangement. The logic emulation board has connectors for connection to a logic emulation module, and lands for supporting LSIs targeted for development. Pins of the connectors and the lands are interconnected on a one-to-one basis.

Abstract: A technique synchronizes logic signals captured in a PLD portion of a PLD system having both a microprocessor and PLD circuitry with executed instructions captured from a microprocessor portion. One or more signal lines connects the microcontroller portion with the PLD portion for transmitting signals between the two portions corresponding to debug operations in each portion. Conventional electronic circuits employing microprocessors and PLD's use independent debugging techniques, either of which are incapable of reflecting the complete state of the circuit at a selected time. Combined processor and PLD systems employ independent clocks for each portion, thus creating additional problems in synchronizing logic state traces in the PLD with the microprocessor instruction traces. The present invention provides a direct signals from the PLD portion to the microcontroller portion upon the occurrence of events relating to debugging and debug modes of the microprocessor.

Abstract: A data accelerator for use in a test vector sequencer includes a data translator, a plurality of sequence memory devices, and a switch. The data translator and the switch are configured via a control signal responsive to an indication that a first sequence memory device is prepared to receive a data segment and that a second sequence memory device is prepared to transfer a previously stored data segment. The test sequencer forwards a first application segment to a first memory device and acquires a subsequent application with a second memory device, detects a condition responsive to the completion of the segment acquisition and forwarding tasks, switches the roles of the first and second memory devices, and repeatedly switches and detects until all application segments have been processed.

Abstract: A first dynamic logic circuit has an output node on which a scan value is provided during scan. One of one or more second dynamic logic circuits has an input coupled to the output node of the first dynamic logic circuit, and an output of the second dynamic logic circuits is sampled in response to the scan value during scan. In one embodiment, clock generation circuitry may be included which generates a first clock, a second clock, and a third clock. At least one evaluate pulse on the first clock prior is generated prior to sampling the output of the second dynamic logic circuits, the first clock controlling at least the evaluation of the second dynamic logic circuits. The second and third clocks are generated to isolate the output node from inputs to the first dynamic logic circuit responsive to the scan mode signal indicating that scan is active.

Abstract: A method and apparatus are disclosed for easily reconfiguring a scan chain test of a subset of scan blocks within a digital integrated circuit chip. To mitigate timing violations in the scan test of scan chains, alternative embodiments to implement a transfer of scan data to a next scan block is implemented.

Abstract: The present invention includes a system and method for generating a signal particularly useful in testing JMX monitors using a generator bean, such as a signal generating Java Mbean. A user can specify equations and/or parameters in order to determine the type of signal to be generated. The generator bean is then polled at a frequency at least twice the frequency of the generated signal using a monitor MBean of the JMX monitor. A testing value is returned for each polling of the generator bean.

Abstract: A method to provide hierarchical reset capabilities for a configurable system on a chip is disclosed. The method includes determining a plurality of reset functions, and establishing a reset hierarchy among the plurality of reset functions.

Abstract: A method and system for testing programmability of a programmable logic device (PLD) having a programmable AND array. The PLD is bulk programmed and verified. If the bulk programming fails, each row of cells of the AND array is programmed individually and the row-by-row programming of the PLD is verified.

Abstract: One embodiment of the present invention provides a system that facilitates fully characterizing propagation delay through an n-input circuit. The system operates by first receiving the n-input circuit. Next, the system establishes programmable voltage sources at each input of the n-input circuit. The system then programs each programmable voltage source to provide a sequence of input patterns to the n-input circuit. This sequence includes the 22n possible transitions between all possible pairs of input patterns. Next, the system measures the propagation delay between the input and the output of the n-input circuit for each transition in the sequence of input patterns and then reports the results.

Abstract: An apparatus comprising a first circuit comprising a JTAG port and a second port. A JTAG non-compliant circuit may be controlled by the JTAG port when connected to the second port.

Abstract: Internal registers of a PLD are exposed for debugging using a JTAG port and a scan chain. The user of a PLD identifies registers at the source code level. These registers are automatically inserted in a scan chain. An EDA software tool provides a means of choosing a register from the electronic design. The EDA tool connects the selected register to the JTAG scan chain and passes information to the software about the location in the scan chain. The EDA tool provides for scanning of the chain under automatic or manual control. The selected nodes are extracted from the chain and displayed in a user-specified format. Registers in encrypted blocks are exposed. The vendor of the block decides which registers are of importance. Once selected, the vendor creates a “debugging” file which is delivered to the customer along with the encrypted block. The debugging file contains the names of the registers, their data type, and their symbolic values.

Abstract: Described are methods and circuits for identifying defective device layers and localizing defects. Production PLD tests extract statistically significant data relating failed interconnect resources to the associated conductive metal layer. Failure data thus collected is then analyzed periodically to identify layer-specific problems. Test circuits in accordance with some embodiments employ interconnect resources heavily weighted in favor of specific conductive layers to provide improved layer-specific failure data. Some such test circuits are designed to identify open defects, while others are designed to identify short defects.

Abstract: A new method to test short faults in a programmable logic device is described. The line segments under test are connected together to form a conducting chain. All the line segments neighboring to the conducting chain are tied to a known state. A test vector is applied to the programmable logic device. The state of the line under test is measured. If it is the same as the known state, the programmable logic device is likely to have faults.

Abstract: A static output signal is generated using a static storage element (104) and transmitted to a NDL gate (110) over a transmission path (112) that is characterized by a user-specified multi-cycle timing constraint that is used to create appropriate verification tests of the apparatus. The multi-cycle timing constraint may be a pragma that is interpreted by the compiler of a timing analysis tool such as PATHMILL to automatically check the set-up and hold times of the static signal relative to the rising edge or falling edge of user-specified clock signal pulses. The same pragma is interpreted by the compiler of a functional verification tools such as VIS to create statements that test the behavior of the apparatus during the clock signal pulses other than the user-specified clock signal pulses tested by the timing analysis tool.

Abstract: Embedding a logic analyzer in a programmable logic device allows signals to be captured both before and after a trigger condition (breakpoint). A logic analyzer embedded within a PLD captures and stores logic signals. It unloads these signals for viewing on a computer. Using an electronic design automation (EDA) software tool running on a computer system, an engineer specifies signals of the PLD to be monitored, a breakpoint, total number of samples to be stored, number of samples to be captured after the breakpoint occurs, and a system clock signal. The EDA tool automatically inserts the logic analyzer into the electronic design of the PLD which is compiled and downloaded to configure the PLD. Using an interface connected between the PLD and the computer, the EDA tool commands the embedded logic analyzer to run. Signals are stored continuously while running in a ring buffer RAM memory. Once the breakpoint occurs, more samples are captured if desired, in addition to those signals captured before breakpoint.

Abstract: A method of inducing a fault within the boundary of an on-card reprogrammable logic device (RLD) by interactive injection of subtle candidate faults and comparison of expected error message from software diagnostics until all faults are tested. Upon completion of fault injection, the RLD is reprogrammed to its proper functional faultless state.

Abstract: The present invention provides a method and mechanism for simulating complex digital circuits using hybrid control and data flow representations. Specifically, the invention provides a method of simulating a digital circuit in such a way that the simulation is stopped at desired functions for subsequent analysis. A hardware design code describing the digital circuit is converted to an assignment decision diagram (ADD) representation that is then annotated with one or more control nodes that are used for maintaining control flow through a simulator. In this way, one or more break points are created that allow the simulator to stop at associated points in the simulation.

Abstract: A hardware emulation system is disclosed which reduces hardware cost by time-multiplexing multiple design signals onto physical logic chip pins and printed circuit board. The reconfigurable logic system of the present invention comprises a plurality of reprogrammable logic devices, and a plurality of reprogrammable interconnect devices. The logic devices and interconnect devices are interconnected together such that multiple design signals share common input/output pins and circuit board traces. A logic analyzer for a hardware emulation system is also disclosed. The logic circuits necessary for executing logic analyzer functions is programmed into the programmable resources in the logic chips of the emulation system. A method for dynamically testing the interconnect between integrated circuits is also disclosed.

Abstract: In a programmable logic device having dedicated multiplier circuitry, some of the scan chain registers normally used for testing the device are located adjacent input registers of the multipliers. Those scan chain registers are ANDed with the input registers, and can be loaded with templates of ones and zeroes. This allows, e.g., subset multiplication if the least significant bits are loaded with zeroes and the remaining bits are loaded with ones. The multipliers preferably are arranged in blocks with other components, such as adders, that allow them to be configured as finite impulse response (FIR) filters. In such configurations, the scan chain registers can be used to load filter coefficients, avoiding the use of scarce logic and routing resources of the device.

Abstract: Methods of optimizing the use of routing resources in programmable logic devices (PLDs) to minimize test time. A set of routing resources is identified that are not used in most designs, and a device model is provided to the user that prevents the use of these resources. Because the routing resources will never be used, they need not be tested by the PLD manufacturer, significantly reducing the test time. For example, each PLD within a PLD family is typically designed using a different number of similar tiles. Thus, smaller PLDs in the family include an unnecessarily large number of routing resources. These excessive routing resources can be disabled during implementation of a design. In another example, each tile along the edges of an array includes routing resources designed primarily to provide access to tiles that are not present. These redundant routing resources can be disabled during implementation of a design.

Abstract: A technique to implement functions requiring fewer pins of an integrated circuit to serially transfer data into the integrated circuit for multiple logic blocks. By reducing the required pins, this permits downbonding of the integrated circuit into a package with fewer pins. This technique may be used to implement test functions in a programmable logic device. Test data may be serially input using a test pin (310) for two or more columns (320) of logic blocks. The test data is stored in an A register (330), and may be later transferred into a B register (335).

Abstract: A first dynamic logic circuit has an output node on which a scan value is provided during scan. One of one or more second dynamic logic circuits has an input coupled to the output node of the first dynamic logic circuit, and an output of the second dynamic logic circuits is sampled in response to the scan value during scan. In one embodiment, clock generation circuitry may be included which generates a first clock, a second clock, and a third clock. At least one evaluate pulse on the first clock prior is generated prior to sampling the output of the second dynamic logic circuits, the first clock controlling at least the evaluation of the second dynamic logic circuits. The second and third clocks are generated to isolate the output node from inputs to the first dynamic logic circuit responsive to the scan mode signal indicating that scan is active.

Abstract: Methods of detecting shorts affecting nets of a specified design in a partially defective PLD. The nets participating in the design are identified, along with the interconnect lines used to implement each net. The nets are then divided into two or more groups, where no two nets in a single group can be shorted together by the inadvertent enablement of a single programmable interconnect point between two interconnect lines. The groups are then tested for inadvertent shorts. According to a first aspect of the invention, each group is tested sequentially against all interconnect lines not in the group, or against all nets in other groups. According to another aspect, the groups are tested simultaneously by applying a different stimulus pattern to each group. By comparing a detected value pattern to the stimulus patterns applied to other groups, it can be determined which two groups are participating in the short.

Abstract: A programmable logic device comprising a macro-cell flip-flop configured to store (i) a first input when the programmable logic device is in a normal mode and (ii) a second input when the programmable logic device is in a test mode.

Abstract: A programmable logic device (PLD) has the ability to test the configuration memory either independently or during configuration. The PLD may include a selector for selecting a particular column or row of the configuration memory array, and an input data storage device for storing configuration data required to be stored in the selected column or row, or test data for testing the selected column or row. The PLD may also include an output data storage device for storing the output from the selected column or row, and test logic that provides control signals for verifying the correct operation of the data lines of the configuration memory array without disturbing the data stored in the memory array.

Abstract: There is disclosed a field programmable gate array for use in an integrated processing system capable of testing other embedded circuit components in the integrated processing system. The field programmable gate array detects a trigger signal (such as a power reset) in the integrated processing system. In response to the trigger signal, the field programmable gate array receives first test program instructions from a first external source and executes the first test program instructions in order to test the other embedded circuit components in the integrated processing system. When testing of the other embedded circuit components is complete, the field programmable gate array loads its normal operating code and performs its normal functions.

Abstract: The invention is directed to techniques which use a test circuit within an FPGA device to obtain a trace of a digital signal used by normal operating circuitry of the FPGA device. The test circuit stores the trace in memory of the FPGA device which is accessible without the need of a logic analyzer (e.g., accessible in a memory mapped or I/O mapped manner). Accordingly, the deficiencies of a conventional built-in approach (e.g., including a mounted connector and connections by sacrificing circuit board area) and soldering approach (e.g., soldering wires to the circuit board requiring time and effort, and increasing the likelihood of signal distortion) for logic analyzer access are avoided. One arrangement of the invention is directed to a computer system having a bus, a processor coupled to the bus, and an FPGA device coupled to the bus.

Abstract: Method and system for testing circuitry of a programmable logic device (PLD). A host data processing arrangement is configured with a run-time reconfiguration programming interface, and a run-time reconfiguration test program that invokes methods of the interface executes on the host arrangement. In response to a method of the programming interface invoked from the test program, the PLD is configured with a first configuration bitstream. State data are then read back from the PLD in response to a method of the programming interface invoked from the test program. The test program also identifies differences between the state data and expected-results data.

Abstract: A field programmable device is disclosed, including a plurality of logic blocks; a plurality of connections connecting the logic blocks; configuration circuitry for outputting configuration data for programming the field programmable device, the configuration circuitry providing at least one pair of outputs; and error detection circuitry for comparing the outputs to determine if there has been a configuration error.

Abstract: An interface architecture is presented for Field Programmable Gate Array (FPGA) cores by which an FPGA core can be embedded into an integrated circuit and easily configured and tested without detailed knowledge of the FPGA core. A microcontroller coupled to the FPGA core has a general instruction set that provides access to all resources within the FPGA core. This enables high level services, such as configuration loading, configuration monitoring, built in self test, defect analysis, and debugger support, for the FPGA core upon instructions from a host interface. The host interface, which modifies the instructions from a processor unit, for example, for the microcontroller, provides an adaptable buffer unit to allow the FPGA core to be easily embedded into different integrated circuits.

Abstract: A method of testing field programmable gate array (FPGA) resources and identifying faulty FPGA resources during normal on-line operation includes configuring an FPGA into a working area and an initial self-testing area. The working area maintains normal operation of the FPGA throughout testing and identifying of the resources. Within the initial and subsequent self-testing areas, the FPGA resources are initially tested for faults. Upon detection of a fault in the FPGA resources, the initial self-testing area resources are reconfigured or subdivided and further tested in order to identify the faulty resource. Dependent upon the further test results, the FPGA resources may be further subdivided and tested until the faulty resource is identified. Once the faulty resource is identified, the FPGA is reconfigured to replace unusable faulty resources or to avoid faulty modes of operation of partially faulty resources diagnosed during further testing.

Abstract: An integrated circuit is characterized in that circuit parts contained therein are connected to one another via an interface containing at least one scan register chain. The at least one scan register chain is configured such that data can be input into the scan register chain either via the output terminals of one of the circuit parts or via the input and/or output terminals of the integrated circuit. In addition, data can be output from the scan register chain either at the input terminals of one of the circuit parts or at the input and/or output terminals of the integrated circuit.

Abstract: A method is provided for analyzing the functionality of an integrated circuit (IC). The method includes the step of applying a built-in self test (BIST) to the integrated circuit. The BIST includes a plurality of tests that result in the integrated circuit passing and/or failing with respect to predefined criteria. During the applying step, a substrate current of the integrated circuit is measured and analyzed as a function of at least one variable. Also during the applying step, optical emissions of the integrated circuit are measured and analyzed. Defects in the functionality of the integrated circuit are identified, based on at least one of the substrate current and the optical emissions.

Abstract: The invention is directed to techniques for accessing an external device, e.g., a device under test (DUT), from an automatic test equipment (ATE) interfacing apparatus, e.g., a specialized tester or channel card device. In one arrangement, the ATE interfacing apparatus includes a test bus interface for connecting to a test bus of an automatic test system; an external device interface for connecting to an external device; and a translator, interconnected between the test bus interface and the external device interface. The translator receives a memory access instruction from the test bus through the test bus interface. The memory access instruction includes a command and a test bus address. The translator translates the test bus address into an identifier which identifies a portion of the external device, and accesses the identified portion of the external device through the external device interface based on the command and the identifier.

Abstract: A configuration memory for storing information which is in-system programmable. The programming of the configuration memory may be performed using JTAG (IEEE Standard 1149.1) instructions. Furthermore, the configuration of a programmable logic device using the configuration data in the configuration memory may be initiated with a JTAG instruction. Pull-up resistors are incorporated within the configuration memory package.

Abstract: A CPLD employs a low-voltage, non-degenerative transmitter circuit to eliminate the need for a dedicated control pin to provide the relatively high voltage levels required to verify the program states of programmable memory cells. Eliminating the need for a dedicated control pin frees up valuable chip real estate for the inclusion of an additional general-purpose input/output pin.

Abstract: A method of efficiently designing, implementing, and verifying programmed PLDs that includes translating simulation test vectors that are generated by design automation software into device level test vectors. Each of the device level test vectors is substantially identical to one of the simulation test vectors and is readable by automatic testers. Thus, the operation of programmed PLDs can be thoroughly and efficiently verified at the device level using the same test stimuli as a simulation test model.

Abstract: A new testing method uses a field programmable gate array to emulate faults, instead of using a separate computer to simulate faults. In one embodiment, a few (e.g., two or three) known good FPGAs are selected. A fault is introduced into the design of a FPGA configuration. The configuration is loaded into the FPGAs. A test vector is applied and the result is evaluated. If the result is different from that of a fault-free configuration, the fault is caught. One application of this method is to evaluate fault coverage. A fault model that can be used in the present invention is disclosed.

Abstract: A ramp-up circuit on an integrated circuit receives a relatively high program (erase) voltage for changing the program state of a memory cell. The ramp-up circuit gradually raises the program (erase) voltage to prevent damage to the memory cell. The ramp-up circuit includes a pass gate and associated control circuitry that provides a controlled, ramped-up version of the program (erase) voltage to the memory cell without raising internal circuit nodes above the program (erase) voltage.

Abstract: An application specific integrated circuit (ASIC) is disclosed. The ASIC includes a standard cell. The standard cell includes a plurality of logic functions. The ASIC also includes at least one bus coupled to at least a portion of the logic functions and a plurality of internal signals from the plurality of logic functions. Finally, the ASIC includes a field programmable (FP) function coupled to the at least one bus and at least a portion of the plurality of internal signals. The FP function provides access to internal signals for observation and control. An ASIC using a field programmable gate array (FPGA) function within a standard cell design is utilized to create an internal-to-the-ASIC bridging of internal signals to observe and control of the internal signals of the ASIC. By the placement of logic, which expresses a test program, into the FPGA function that manipulates the I/O pins and/or other functional entities of interest, the ASIC function and/or surrounding logic can be easily verified.

Abstract: An application specific integrated circuit (ASIC) is disclosed. The ASIC includes a standard cell. The standard cell includes a plurality of logic functions and at least one bus coupled to at least a portion of the logic functions. The standard cell also includes a plurality of internal signals from the plurality of logic functions and a field programmable gate array (FPGA) function coupled to the at least one bus and at least a portion of the plurality of internal signals. The FPGA function includes a debug client function that observes and manipulates the at least one bus and the plurality of internal signals. A system and method in accordance with the present invention utilizes a debug function within a standard cell design to create an internal-to-the-ASIC debugging (software, hardware or both) function. The system and method is provided by connection of internal buses and signals of interest to a debug client function within the FPGA function.

Abstract: A method of self-testing the programmable routing network in a field programmable gate array (FPGA) during normal on-line operation includes configuring the FPGA into an initial self-testing area and a working area. The initial self-testing area is preferably configured to include an horizontal self-testing area primarily for testing horizontal wire segments and a vertical self-testing area primarily for testing vertical wire segments. Programmable logic blocks located within the self-testing areas are configured to function as a test pattern generator and an output response analyzer, and a portion of the programmable routing resources within the self-testing areas is configured as groups of wires under test. An exhaustive set of test patterns generated by the test pattern generator is applied to the groups of wires under test which are repeatedly reconfigured in order to completely test the programmable routing resources within the self-testing areas.

Abstract: An improved system and method for increasing system throughput and data capacity in a circuit tester capable of programming and/or testing in-circuit integrated circuit devices are disclosed. A data accelerator for use in a test vector sequencer can be realized with a data translator, a plurality of sequence memory devices, and a switch. In preferred embodiments, the data translator and the switch are configured via a single control signal responsive to an indication that a first sequence memory device is prepared to receive a data segment and that a second sequence memory device is prepared to transfer a previously stored data segment.

Abstract: In a programmable logic device having dedicated multiplier circuitry, some of the scan chain registers normally used for testing the device are located adjacent input registers of the multipliers. Those scan chain registers are ANDed with the input registers, and can be loaded with templates of ones and zeroes. This allows, e.g., subset multiplication if the least significant bits are loaded with zeroes and the remaining bits are loaded with ones. The multipliers preferably are arranged in blocks with other components, such as adders, that allow them to be configured as finite impulse response (FIR) filters. In such configurations, the scan chain registers can be used to load filter coefficients, avoiding the use of scarce logic and routing resources of the device.

Abstract: A system and method utilize bitmaps for verifying configuration of a programmable logic device (PLD). A configuration bitstream containing configuration commands and data is converted to a configuration bitmap. The configuration bitstream is downloaded to PLD, thus programming the PLD. Readback commands and data read back from the PLD are used to generate a readback bitstream. The readback bitstream is then converted to a readback bitmap. Bits at corresponding cell locations in the readback bitmap and the configuration bitmap are compared. An error signal is output if the bits are different. In one embodiment, a mask bitmap is generated to indicate which cell locations are non-configuration memory cells and thus need not be compared.

Abstract: The present invention adds a programmable expect generator (PEG) that generates expected patterns of output for comparison to the actual outputs of an array while undergoing a complex test input sequence. The output of a programmable array built-in self test (PABIST) controller has its output increased to include separate control bits and a mask bit for a PEG. The PEG in one embodiment of the invention is substantially similar to a data control register that is programmed by a sequence of commands to generate the array input data patterns for testing an array. The program sequence that controls the PABIST and generates the input address, data and read/write patterns also outputs separate control bits to direct the PEG to generate expected outputs from the array when data from corresponding read addresses are read. The incorporation of a mask bit that accompanies each group of PEG control bits is used to inhibit the compare function that compares the output of the array to the output of the PEG.

Abstract: A method of self-testing the programmable logic blocks of field programmable gate arrays (FPGAs) during normal on-line operation includes configuring the FPGA into an initial self-testing area and a working area. The self-testing area may be further subdivided into self-testing tiles for concurrent testing if desired. The programmable logic blocks located within the self-testing area or self-testing tiles are established to function as a test pattern generator, an output response analyzer, and equivalently configured programmable logic blocks under test for testing. An exhaustive set of test patterns generated by the test pattern generator are applied to the programmable logic blocks under test which are repeatedly reconfigured in order to completely test the programmable logic blocks in all possible modes of operation.

Abstract: A method and apparatus for tracing hardware states using dynamically reconfigurable test circuits provides improved debug and troubleshooting capability for functional logic implemented within field programmable logic arrays (FPGAs). Special test logic configurations may be loaded to enhance the debugging of a system using FPGAs. Registers are used to capture snapshots of internal signals for access by a trace program and a test multiplexer is used to provide real-time output to test pins for use with external test equipment. By retrieving the hardware snapshot information with a trace program running on a system in which the FPGA is used, software and hardware debugging are coordinated, providing a sophisticated model of overall system behavior. Special test circuits are implemented within the test logic configurations to enable detection of various events and errors. Counters are used to capture count values when system processor execution reaches a hardware trace point or when events occur.

Abstract: A technique to implement functions requiring fewer pins of an integrated circuit to serially transfer data into the integrated circuit for multiple logic blocks. By reducing the required pins, this permits downbonding of the integrated circuit into a package with fewer pins. This technique may be used to implement test Functions in a programmable logic device. Test data may be serially input using a test pin (410) for two or more columns (320) of logic blocks. The test data is stored in an A resister (330), and may be later transferred into a B register (335).

Abstract: A method of fault tolerant operation of field programmable gate arrays (FPGAs) utilizing incremental reconfiguration during normal on-line operation includes configuring an FPGA into initial self-testing areas and a working area. Within the self-testing areas, programmable logic blocks (PLBs) of the FPGA are tested for faults. Upon the detection of one or more faults within the PLBs, the faulty PLBs are isolated and their modes of operation exhaustively tested. Partially faulty PLBs are allowed to continue operation in a diminished capacity as long as the faulty modes of operation do not prevent the PLBs from performing non-faulty system functions. After testing the programmable logic blocks in the initial self-testing areas, the FPGA is reconfigured such that a portion of the working area becomes a subsequent self-testing area and at least a portion of the initial self-testing area replaces that portion of the working area.