Lucent Technologies Inc.

University of Kentucky Research Foundation

The University of North Carolina at Charlotte

Other

Agere Systems Inc.

Lattice Semiconductor Corporation

Auburn University

Charles Eugene Stroud

Miron Abramovici

John M Emmert

Ramesh Karri

Fa Dai

Shianling Wu

Sajitha S Wijesuriya

Eric Seng-Kar Lee

A built-in-self test (BIST) scheme for analog circuitry functionality tests such as frequency response, gain, cut-off frequency, signal-to-noise ratio, and linearity measurement. The BIST scheme utilizes a built-in direct digital synthesizer (DDS) as the test pattern generator that can generate various test waveforms such as chirp, ramp, step frequency, two-tone frequencies, sweep frequencies, MSK, phase modulation, amplitude modulation, QAM and other hybrid modulations. The BIST scheme utilizes a multiplier followed by an accumulator as the output response analyzer (ORA). The multiplier extracts the spectrum information at the desired frequency without using Fast Fourier Transform (FFT) and the accumulator picks up the DC component by averaging the multiplier output.

Automatic analog test and compensation with built-in pattern generator and analyzer

Systems and methods for delay-fault testing field programmable gate arrays (FPGA's), applicable both for off-line manufacturing and system-level testing, as well as for on-line testing within the framework of the roving self-test area (STARs) approach are described. In one described method, two or more paths under test receive a test pattern approximately simultaneously. The two paths are substantially identical and thus should propagate the signal in approximately the same amount of time. An output response analyzer receives the signal from each of the paths and determines the interval between them, and then determines whether a delay fault has occurred based at least in part on the interval. The output response analyzer may include an oscillator and a counter. The oscillator generates an oscillating signal during the interval between when the test signal propagates through the first path and the last path under test.

Methods for delay-fault testing in field-programmable gate arrays

A method of fault tolerant operation of field programmable gate arrays (FPGAs), whether as an embedded portion of a system-on-chip or other application specific integrated circuit, utilizing incremental reconfiguration during normal on-line operation includes configuring an FPGA into a self-testing area and a working area. Within the self-testing area, programmable interconnect resources of the FPGA are tested for faults. Upon the detection of one or more faults within the interconnect resources, the faulty interconnect resources are identified and a determination is made whether utilization of the faulty interconnect resources is compatible with an intended operation of the FPGAs. If the faulty interconnect resources are compatible with the intended operation of the FPGA, utilization of the faulty interconnect resource is allowed to provide fault tolerant operation of the FPGA. If the faulty interconnect resources are not compatible with the intended operation of the FPGA, on the other hand, a multi-step reconfiguration process may be initiated which attempts to minimize the effects of each reconfiguration on the overall performance of the FPGA. In an alternate embodiment, the entire FPGA may be configured as one or more self-testing areas during off-line testing, such as manufacturing testing.

Fault tolerant operation of field programmable gate arrays

A method of identifying faulty programmable interconnect resources of a field programmable gate array (FPGA) may be carried out during manufacturing testing and/or during normal on-line operation. The FPGA resources are configured into a working area and a self-testing area. The working area maintains normal operation of the FPGA throughout on-line testing. Within the self-testing area, programmable interconnect resources of the FPGA are grouped and comparatively tested for faults. Upon the detection of one or more faults within a group of programmable interconnect resources, the group of resources is subdivided for further comparative testing in order to minimize a region of the group of resources including the fault for each fault. Once the region of the group of resources which includes the fault is minimized, the wires within the minimized region are comparatively tested in order to determine which wire includes the faulty resource or resources. Once the wire which includes the faulty resource is determined, a variety of testing configurations may be utilized to identify the faulty resource within the wire.

Identifying faulty programmable interconnect resources of field programmable gate arrays

A method of fault tolerant operation of an adaptive computing system includes identifying a faulty resource in a signal path of the adaptive computing system, reconfiguring the signal path to avoid the faulty resource, estimating a time delay created by reconfiguring the signal path, and adjusting a system clock period to accommodate the time delay. In a preferred embodiment, an FPGA is configured into an initial self-testing area and a working area. Resources located within the self-testing area are tested and faulty resources identified. The FPGA is then reconfigured to avoid the identified faulty resources. When the resources are reconfigured for fault tolerant operation, signal path delays may be introduced into the system. If the signal path delays are in a critical path, a period of a system clock may be adjusted in order to insure proper fault tolerant operation.

Fault tolerant operation of reconfigurable devices utilizing an adjustable system clock

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. In this manner, partially faulty resources are allowed to continue operation in a diminished capacity to enhance fault tolerance. After testing each of the FPGA resources located within the initial self-testing area for faults, identifying the faulty resources, and in some instances diagnosing faulty modes of operation of the faulty resource, the FPGA is reconfigured such that a portion of the working area becomes a subsequent self-testing area and the initial self-testing area replaces that portion of the working area. In other words, the self-testing area roves around the FPGA testing its resources in a continuous manner.

On-line testing of field programmable gate array resources

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. The outputs of the groups of wires under test are compared by the output response analyzer and resultant fault status data for each group of wires under test is received by a controller in communication with a memory for storing the fault status data. After completely testing the programmable routing resources in one of 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 one of the initial self-testing areas replaces that portion of the working area. In other words, the self-testing areas rove around the FPGA repeating the steps of testing and reconfiguring until the entire FPGA has undergone testing or continuously.

On-line testing of the programmable interconnect network in field programmable gate arrays

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. The outputs of the logic blocks are compared by the output response analyzer and resultant fault status data for each programmable logic block under test is received by a controller in communication with a memory for storing usage and fault status data for each programmable logic block. After testing each logic block in the initial self-testing area, 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. In other words, the self-testing area roves around the FPGA repeating the steps of testing and reconfiguring the programmable logic blocks until the entire FPGA has undergone testing or continuously.

On-line testing of the programmable logic blocks in field programmable gate arrays

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. In other words, the self-testing area roves around the FPGA repeating the steps of testing and reconfiguring until the entire FPGA has undergone testing, or continuously. Prior to relocating the initial self-testing areas, the initial self-testing areas are reconfigured to replace unusable faulty PLBs with spare PLBs. Spare PLBs are initially allocated throughout the working area. Specifically, each operational PLB within the working area is allocated an adjacent preferred spare PLB. Predetermined configurations of the FPGA utilizing the preferred spares are used to avoid the faulty PLBs. If the initially allocated spares are incapable of utilization, then a subsequent portion of the PLBs within the working area are allocated as spares and new replacement configurations determined. As the number of spare PLBs is diminished over time, additional spare PLBs are at some point necessarily removed from the self-testing areas. In this manner, the testing and roving capabilities of the self-testing area are also inevitably diminished. Eventually, roving, testing, and even operation of the FPGA will cease.

On-line fault tolerant operation via incremental reconfiguration of field programmable gate arrays

A method of fault tolerant reconfiguration and operation of a field programmable gate array (FPGA) during normal on-line operation includes selecting a programmable logic block as a programmable logic block under test, testing the programmable logic block under test, and detecting the existence of any faults in the programmable logic block under test. During testing, the programmable logic block under test is repeatedly reconfigured in order to test the programmable logic block completely in all possible modes of operation. Based on the results of the test, a test result indication is sent to a controller in communication with a memory for storing usage and fault status data for each programmable logic block. If a partially faulty test result indication is present, the controller determines an intended mode of operation of the partially faulty programmable logic block under test and reconfigures the logic block for further use, thus allowing a more gradual degradation of the field programmable gate array.

A method of built-in self-testing field programmable gate arrays (FPGAs) including the programmable logic blocks, the programmable routing networks and the programmable input/output cells or boundary ports at the device, board or system level includes testing the programmable logic blocks, reconfiguring a first group of he programmable logic blocks to include a test pattern generator and an output response analyzer, and configuring the programmable routing network into groups of wires under test. This step is followed by generating test patterns propagated along the wires under test and comparing the outputs utilizing the output response analyzer. Based on the result of the comparison a pass/fail test result indication is routed to the associated boundary port. The results from a plurality of output response analyzers can be compared utilizing an iterative comparator in order to reduce the number of boundary ports required during testing.

Method and apparatus for testing field programmable gate arrays

A method of testing field programmable gate arrays (FPGAs) includes establishing a first group of programmable logic blocks as test pattern generators or output response analyzers and a second group of programmable logic blocks as blocks under test. This is followed by generating test patterns and comparing outputs of two blocks under test with one output response analyzer. Next is the combining of results of a plurality of output response analyzers utilizing an iterative comparator in order to produce a pass/fail indication. The method also includes the step of reconfiguring each block under test so that each block under test is tested in all possible modes of operation. Further, there follows the step of reversing programming of the groups of programmable logic blocks so that each programmable logic block is configured at least once as a block under test.

Method of testing and diagnosing field programmable gate arrays

Concurrent Fault Detector Circuits (CFDCs) are test components of a main system, e.g. an Application Specific Integrated Circuit, and provide the results of the tests in parallel to at least one Error Source Register (ESR). Instead of reading out the ESR in parallel, its contents are copied to a serial shadow register so the contents can be read out in series to an error correcting application, thus reducing the number of output pins and the burden on resources of the main system. The ESR's receipt and transfer of information is under the control of a Boundary Scan Interface. In one embodiment, the test results are prioritized and compared to data in a mask register so that only important errors create a system interrupt which causes the read out of data from the shadow register.

Maintenance registers with Boundary Scan interface

A method of testing field programmable gate arrays (FPGAs) includes the step of configuring programmable logic blocks of the FPGAs for completing a built-in self-test. This is followed by the steps of initiating the built-in self-test, generating test patterns with the programmable logic blocks and analyzing a resulting response to produce a pass/fail indication with the programmable logic blocks. More specifically, the configuring step includes establishing a first group of programmable logic blocks as test pattern generators and output response analyzers and a second group of programmable logic blocks as blocks under test. The blocks under test are then repeatedly recongifured in order to completely test each block under test in all possible modes of operation. The programming of the first and second groups of programmable logic blocks is then reversed and the testing of each new block under test is then completed.

Method for testing field programmable gate arrays

A method of testing field programmable gate arrays (FPGAs) includes the step of configuring programmable logic blocks of the FPGAs for completing a built-in self-test. Specifically, the FPGA under test may be configured to act as an iterative logic array wherein a first group of programmable logic blocks are configured as test pattern generators, output response analyzers and helper cells, and a second group of programmable logic blocks are configured as blocks under test. The blocks under test are then repeatedly reconfigured in order to completely test each block under test in all possible modes of operation. The first and second groups of programmable logic blocks are then repeatedly rearranged so that all the programmable logic blocks are established as blocks under test at least once. Following the rearrangement, the repeated reconfiguration of the blocks under test is performed once again.

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Charlotte, NC, United States of America

Charles Eugene Stroud