Abstract: A method for testing at least two arithmetic units installed in a control unit includes: loading of first test data for testing a first arithmetic unit; saving the loaded first test data in a second memory unit of a second arithmetic unit; switching the first arithmetic unit to a test mode, in which a first scan chain of the first arithmetic unit is accessible; reading the first test data from the second memory unit; shifting the first test data which have been read through the first scan chain of the first arithmetic unit switched to the test mode for providing test result data for the first arithmetic unit; checking the provided test result data for plausibility for providing a test result for the first arithmetic unit.

Abstract: A test architecture accesses IP core test wrappers within an IC using a Link Instruction Register (LIR). An IEEE P1500 standard is in development for providing test access to these individual cores via a test structure called a wrapper. The wrapper resides at the boundary of the core and provides a way to test the core and the interconnections between cores.-The test architecture enables each of the plural wrappers in the IC, including wrappers in cores embedded within other cores, with separate enable signals.

Abstract: Method and apparatus for operating for operating an Institute of Electrical and Electronics Engineers (IEEE) Standard 1149.1 compliant Joint Test Action Group (JTAG) Test Access Port (TAP) controller are disclosed. An example apparatus includes write logic that is configured to operationally interface with a TAP controller and a processor. The write logic is further configured to receive, from the processor, data for initializing the apparatus and operating the TAP controller, convert at least a portion of the data from a parallel format to a serial format and communicate the converted data to the TAP controller.

Abstract: An integrated circuit or circuit board includes functional circuitry and a scan path. The scan path includes a test data input lead, a test data output lead, a multiplexer, and scan cells. A dedicated scan cell has a functional data output separate from a test data output. Shared scan cells each have a combined output for functional data and test data. The shared scan cells are coupled in series. The test data input of the first shared scan cell is connected to the test data output of the dedicated scan cell. The combined output of one shared scan cell is coupled to the test data input lead of another shared scan cell. The multiplexer has an input coupled to the test data output, an input connected to the combined output lead of the last shared scan cell in the series, and an output connected in the scan path.

Abstract: A device and a method for testing a connectivity between a first device and a second device, the method includes: writing, at a first frequency and in a serial manner, a first test word to a source boundary scan register; writing a content of the source boundary scan register, at a second frequency and in a parallel manner, to a target boundary scan register; wherein the second frequency is higher than the first frequency; reading the content of the target boundary scan register; wherein the source and target boundary scan registers are selected from a first boundary scan register of the first device and a second boundary scan register of the second device; and evaluating a connectivity between the first and second device in response to a relationship between the first test word and the content of the target boundary scan register.

Abstract: An optimized JTAG interface is used to access JTAG Tap Domains within an integrated circuit. The interface requires fewer pins than the conventional JTAG interface and is thus more applicable than conventional JTAG interfaces on an integrated circuit where the availability of pins is limited. The interface may be used for a variety of serial communication operations such as, but not limited to, serial communication related integrated circuit test, emulation, debug, and/or trace operations.

Abstract: An approach for producing optimized integrated circuit designs that support sequential flow partial scan testing may be embedded within an integrated circuit electronic design device. Using the approach, an integrated circuit design may be analyzed to identify and remove scan-enabled memory elements, or scan elements, that are redundant. The redundant scan elements may be replaced with memory elements that do not support scan testing. Once the redundant scan elements are removed, the integrated circuit design my be optimized using automated techniques to reduce the area of the integrated circuit physical layout and to simplify/minimize routing connections between remaining features within the integrated circuit design. The described approach may achieve a reduced total area layout and complexity, an improved time/frequency response, and/or reduced power consumption and/or heat generation within the circuit design, without reducing the fault coverage achieve during testing.

Abstract: System and methods transfer data over a microcontroller system test interface. The system can read data from and write data to microcontroller system memory using the described method. The method provides for the efficient transfer of data, minimizing redundancies and overhead present in conventional microcontroller test system protocols.

Abstract: The invention provides an internal comparison circuits for speeding up the ATPG test. During test, an external test machine transfers original test patterns into at least one scan chain of a chip to be tested. A bi-directional output buffer of the chip also receives the test patterns from the test machine. A comparator of the chip compares the original test patterns from the test machine via the bi-directional output buffer group with scanned-out test patterns from the scan chain, to produce a comparison signal indicating whether the chip passes or fails the test.

Abstract: An integrated circuit with low-power built-in self-test logic (“IC-LPBIST”) is disclosed. The IC-LPBIST may include combinational logic and a loading circuit enabled to load a shift test pattern of data into the loading circuit without powering the combinational logic of the IC-LPBIST, wherein the shift test pattern of data is configured to test the combinational logic for logical faults.

Abstract: This disclosure describes a reduced pin bus that can be used on integrated circuits or embedded cores within integrated circuits. The bus may be used for serial access to circuits where the availability of pins on ICs or terminals on cores is limited. The bus may be used for a variety of serial communication operations such as, but not limited to, serial communication related test, emulation, debug, and/or trace operations of an IC or core design. Other aspects of the disclosure include the use of reduced pin buses for emulation, debug, and trace operations and for functional operations. In a fifth aspect of the present disclosure, an interface select circuit, FIGS. 41-49, provides for selectively using either the 5 signal interface of FIG. 41 or the 3 signal interface of FIG. 8.

Abstract: Scan testing of plural target electrical circuits, such as circuits 1 through N, becomes accelerated by using the scan test response data output from one circuit, such as circuit 1, as the scan test stimulus data for another circuit, such as circuit 2. After reset, a scan path captures the output response data from the reset stimulus from all circuits. A tester then shifts the captured data only the length of the first circuit's scan path while loading the first circuit's scan path with new test stimulus data. The new response data from all the circuits then is captured in the scan path. This shift and capture cycle is repeated until the first circuit is tested. The first circuit is then disabled and any remaining stimulus data is applied to the second circuit. This process is repeated until all the circuits are tested. A data retaining boundary scan cell used in the scan testing connects the output of an additional multiplexer as the input to a boundary cell.

Abstract: An adaptation of a test data register (TDR) structure defined by the IEEE 1149.1 Joint Tag Action Group (JTAG) interface standard to provide a debugging path. Existing multi-core processor solutions are covered, but an expansion for a more generic solution is provided. In general, the present apparatus is for extending the IEEE 1149.1 JTAG standard to provide an asynchronous protocol for bypassing test circuitry and bi-directionally communicating with functional circuitry. The apparatus includes an integrated circuit having function register and JTAG standard TDR. Digital logic is configured to control the direct transfer of data between the JTAG standard TDR and the function register.

Abstract: An integrated circuit includes a plurality of logic circuits and a scan chain for testing the plurality of logic circuits. The plurality of logic circuits include the first and second logic circuits. The scan chain includes the first and second scan chain portions. The first scan chain portion is configured to test the first logic circuit based on a scan input test pattern applied thereto and output the first output test pattern. The second scan chain portion is configured to test the second logic circuit based on the first output test pattern and output the second output test pattern. A switching unit is provided to select and output one of the first output test pattern and the second output test pattern as a scan output test.

Abstract: Proposed are methods and apparatuses for synthesis of a new class of compressors called augmented multimode compactors, capable of achieving a flexible trade-off between compaction ratio, observability, control data volume and diagnostic properties in the presence of a large number of unknown values. The augmented multimode compactors reduce and/or completely avoid the X-masking effect in the compacted test responses. In addition, a requirement for constructing compactors is that any single error in the test response produces a unique erroneous signature within S consecutive shift cycles where the erroneous signature is calculated as a difference between the faulty signature and the fault-free signature.

Abstract: A method is provided to evaluate whether one or more test patterns is power safe for use during manufacturing testing of an integrated circuit that includes a nonuniform power grid and that includes a scan chain, the method comprising: assigning respective toggle count thresholds for respective power grid regions of the non-uniform power grid; and determining whether respective numbers of toggles by scan elements of the scan chain within one or more respective power grid regions meet respective toggle count thresholds for the one or more respective regions during at least one scan-shift cycle in the course of scan-in of a test pattern to the scan chain.

Abstract: In a first embodiment a TAP of IEEE standard 1149.1 is allowed to commandeer control from a WSP of IEEE standard P1500 such that the P1500 architecture, normally controlled by the WSP, is rendered controllable by the TAP. In a second embodiment (1) the TAP and WSP based architectures are merged together such that the sharing of the previously described architectural elements are possible, and (2) the TAP and WSP test interfaces are merged into a single optimized test interface that is operable to perform all operations of each separate test interface. One approach provides for the TAP to maintain access and control of the TAP instruction register, but provides for a selected data register to be accessed and controlled by either the TAP+ATC or by the discrete CaptureDR, UpdateDR, TransferDR, ShiftDR, and ClockDR WSP data register control signals.

Abstract: Standardized scan cell logic is enabled to test board-level and circuit-level AC interfaces built into integrated CMOS circuits by verification of high-speed AC coupled non-CMOS logic level signals driven onto non-CMOS logic level AC coupled interconnects in those circuits.

Abstract: An addressable interface selectively enables JTAG TAP domain operations or Trace domain operations within an IC. After being enabled, the TAP receives TMS and TDI input from a single data pin. After being enabled, the Trace domain acquires data from a functioning circuit within the IC in response to a first clock and outputs the acquired data from the IC in response to a second clock. An addressable two pin interface loads and updates instructions and data to a TAP domain within the IC. The instruction or data update operations in multiple ICs occur simultaneously. A process transmits data from an addressed target device to a controller using data frames, each data frame comprising a header bit and data bits. The logic level of the header bit is used to start, continue, and stop the data transmission to the controller.

Abstract: The disclosure provides a novel method and apparatus for inputting addresses to devices to select the device TAP for access. Further, the disclosure provides a novel method and apparatus for inputting addresses for selecting device TAPs and for inputting commands for commanding circuitry within the device. The inputting of addresses or the inputting of addresses and commands is initiated by a control bit input on TDI that is recognized during the Run Test/Idle, Pause-DR or Pause-IR TAP states.

Abstract: Two common varieties of test interfaces exist for ICs and/or cores, the IEEE 1149.1 Test Access Port (TAP) interface and internal scan test ports. The TAP serves as a serial communication port for accessing a variety of circuitry including; IEEE 1149.1 boundary scan circuitry, built in self test circuitry, internal scan circuitry, IEEE 1149.4 mixed signal test circuitry, IEEE P5001 in-circuit emulation/debug circuitry, and IEEE P1532 in-system programming circuitry. Internal scan test ports serve as a serial communication port for primarily accessing internal scan circuitry within ICs and cores. Today, the TAP and internal scan test ports are typically viewed as being separate test interfaces, each utilizing different IC pins and/or core terminals.

Abstract: Synchronization management is provided for a continuous serial data streaming application wherein the serial data stream includes a plurality of consecutive, identical-length segments of consecutive serial data bits. Synchronization management bits are provided in each segment. The synchronization management bits are programmed such that the synchronization management bits contained in first and second adjacent segments of the serial data stream will bear a predetermined relationship to one another. At the receiving end, the synchronization management bits are examined from segment to segment. In this manner, synchronization can be monitored, synchronization loss can be detected, and synchronization recovery can be achieved.

Abstract: A test architecture accesses IP core test wrappers within an IC using a Link Instruction Register (LIR). An IEEE P1500 standard is in development for providing test access to these individual cores via a test structure called a wrapper. The wrapper resides at the boundary of the core and provides a way to test the core and the interconnections between cores. The test architecture enables each of the plural wrappers in the IC, including wrappers in cores embedded within other cores, with separate enable signals.

Abstract: An integrated circuit carries an intellectual property core. The intellectual property core includes a test access port 39 with test data input leads 15, test data output leads 13, control leads 17 and an external register present, ERP lead 37. A scan register 25 encompasses the intellectual property core and ERP lead 37 carries a signal indicating the presence of the scan register.

Abstract: An interface for converting a traditional scan-chain interface into one where locations in the scan-chain can be read or written to from an addressed interface is provided. The interface of the invention includes a scratch pad memory into which the values at the locations in the scan-chain are copied. Those copies in the scratch pad can be read and written to using an addressed interface and if any are changed the values held in the scratch pad are shifted out to update those in the original locations in the scan-chain.

Abstract: The present disclosure describes using the JTAG Tap's TMS and/or TCK terminals as general purpose serial Input/Output (I/O) Manchester coded communication terminals. The Tap's TMS and/or TCK terminal can be used as a serial I/O communication channel between; (1) an IC and an external controller, (2) between a first and second IC, or (3) between a first and second core circuit within an IC. The use of the TMS and/or TCK terminal as serial I/O channels, as described, does not effect the standardized operation of the JTAG Tap, since the TMS and/or TCK I/O operations occur while the Tap is placed in a non-active steady state.

Abstract: A output storage latch within a combinational logic circuit may be adapted to form a scan flip-flop latch that supports both functional operation and scan chain testing of a combinational logic matrix included in the combinational logic circuit. A described master/slave clock approach allows the scan flip-flop latch to support receiving into a scan chain a sequence of test input data, execution of combinational logic matrix testing based on the test input data, and sequentially outputting test results to a test result register for comparison with expected results. The described scan flip-flop latch may be used along side unaltered output storage latches thereby allowing flexibility with respect to the number and placement scan chain test points within an integrated circuit. Use of the described dual-use scan flip-flop latch results in a less complex circuit design, reduced circuit area requirements and improved reliability.

Abstract: The disclosure describes a process and apparatus for accessing devices on a substrate. The substrate may include only full pin JTAG devices (504), only reduced pin JTAG devices (506), or a mixture of both full pin and reduced pin JTAG devices. The access is accomplished using a single interface (502) between the substrate (408) and a JTAG controller (404). The access interface may be a wired interface or a wireless interface and may be used for JTAG based device testing, debugging, programming, or other type of JTAG based operation.

Abstract: A testing circuit has a shift register circuit (76) for storing instruction data for the testing of an integrated circuit core. Each stage of the shift register circuit comprises a first shift register storage element (32) for storing a signal received from a serial input (wsi) and providing it to a serial output (wso) in a scan chain mode of operation, and a second parallel register storage element (38) for storing a signal from the first shift register storage element and providing it to a parallel output in an update mode of operation. The testing circuit further comprises a multiplexer (70) for routing either a serial test input to the serial input (wsi) of the shift register circuit or an additional input (wpi[n]) into the serial input of the shift register circuit (76).

Abstract: A method of testing an integrated circuit, comprises providing a test vector to a shift register arrangement by providing test vector bits in series into the shift register arrangement (20) timed with a first, scan, clock signal (42). The test vector bits are passed between adjacent portions of the shift register arrangement timed with the first clock signal (42) and an output response of the integrated circuit to the test vector is provided and analyzed. The output response of the integrated circuit to the test vector is provided under the control of a second clock signal (56) which is slower than the first clock signal. This testing method speeds up the process by increasing the speed of shifting test vectors and results into and out of the shift register, but without comprising the stability of the testing process. Furthermore, the method can be implemented without requiring additional complexity of the testing circuitry to be integrated onto the circuit substrate.

Abstract: Scan architectures are commonly used to test digital circuitry in integrated circuits. The present invention describes a method of adapting conventional scan architectures into a low power scan architecture. The low power scan architecture maintains the test time of conventional scan architectures, while requiring significantly less operational power than conventional scan architectures. The low power scan architecture is advantageous to IC/die manufacturers since it allows a larger number of circuits (such as DSP or CPU core circuits) embedded in an IC/die to be tested in parallel without consuming too much power within the IC/die. Since the low power scan architecture reduces test power consumption, it is possible to simultaneously test more die on a wafer than previously possible using conventional scan architectures. This allows wafer test times to be reduced which reduces the manufacturing cost of each die on the wafer.

Abstract: A method of in system diagnostics through scan matrix, and an integrated circuit chip in which the diagnostics are performed, are disclosed. The integrated circuit chip operable in a plurality of Boundary Scan test modes in which at least a part of the circuitry in the integrated circuit chip is tested, the integrated circuit chip comprises a scan matrix controller and an instruction register. The scan matrix controller is provided for partitioning said circuitry into multiple matrices, each of the matrices having a plurality of scan elements. The instruction register is provided for holding instructions for the scan matrix controller for partitioning the chip into said multiple matrices. The scan matrix controller is further arranged to test each of said matrices according to instructions in the instruction register by applying a test signal to the tested part of the circuitry.

Abstract: A process and apparatus provide a JTAG TAP controller (302) to access a JTAG TAP domain (106) of a device using a reduced pin count, high speed DDR interface (202). The access is accomplished by combining the separate TDI and TMS signals from the TAP controller into a single signal and communicating the TDI and TMS signals of the single signal on the rising and falling edges of the TCK driving the DDR interface. The TAP domain may be coupled to the TAP controller in a point to point fashion or in an addressable bus fashion. The access to the TAP domain may be used for JTAG based device testing, debugging, programming, or other type of JTAG based operation.

Abstract: For a control apparatus to be boundary scan testable even when running, including processor cores in an operator to be capable of self-repairing a troubling part, an operator (2) has processor cores (2a, 2b) connected to a boundary scan bus (12), and adapted to mutually diagnose opponent processor cores for troubles, by boundary scan testing each other in a time-dividing manner.

Abstract: This disclosure describes a reduced pin bus that can be used on integrated circuits or embedded cores within integrated circuits. The bus may be used for serial access to circuits where the availability of pins on ICs or terminals on cores is limited. The bus may be used for a variety of serial communication operations such as, but not limited to, serial communication related test, emulation, debug, and/or trace operations of an IC or core design. Other aspects of the disclosure include the use of reduced pin buses for emulation, debug, and trace operations and for functional operations.

Abstract: A scan element with self scan-mode toggle is described. In an example, the scan element is configured to automatically switch between a capture mode and a scan mode. In the capture mode, data is captured from logic under test. In the scan mode, the captured data is scanned out for testing. The scan elements each include a shift register that serves a dual purpose of providing control for determining when the scan element is to switch from the capture mode and the scan mode, as well as providing a location to store captured data.

Abstract: An integrated circuit on a semiconductor chip with a plurality of registers distributed across the semiconductor chip. The registers are writeable and readable. The integrated circuit comprises a central control block. The integrated circuit comprises a plurality of circuit units. The circuit unit includes a functional portion with a local clock controller and one or more of the registers. The circuit unit includes a satellite portion. The central control block and the satellite portions are serially connected together and form a scan chain, wherein the scan chain is formed as a ring.

Abstract: Various methods and apparatuses are described for a system that includes some on-chip components, e.g., I-Os, test processors, soft wrappers, etc., an external testing unit that provides Parametric Measurement Unit (PMU) capability, and various tests performed on the I-Os by the on-chip testing logic, the test vector patterns supplied by the external testing unit.

Abstract: Various methods and apparatuses are described for a system that includes some on-chip components, e.g., I-Os, test processors, soft wrappers, etc., an external testing unit that provides Parametric Measurement Unit (PMU) capability, and various tests performed on the I-Os by the on-chip testing logic, the test vector patterns supplied by the external testing unit.

Abstract: A method for determining that failures in semiconductor test are due to a defect potentially causing a hold time violation in a scan cell in a scan chain, counting the number of potential defects, and, if possible, localizing, and ameliorating hold time defects in a scan chain.

Abstract: A method and circuit implement testing of a circuit path including a memory array and logic including Logic Built in Self Test (LBIST) diagnostics, and a design structure on which the subject circuit resides are provided. Testing of the circuit path includes initializing the memory array in the circuit path with an initialization pattern, switching to Logic Built in Self Test (LBIST) mode and providing a read only mode for the memory array, and running Logic Built in Self Test (LBIST) testing of the circuit path.

Abstract: A TAP linking module (21, 51) permits plural TAPs (TAPs 1-4) to be controlled and accessed from a test bus (13) via a single TAP interface (20).

Abstract: A method and circuits for testing an integrated circuit at functional clock frequency by providing a test controller generating control signals that assure proper latching of test patterns in scan chains at tester frequency and propagation of the test pattern through logic circuits being tested at functional clock frequency.

Abstract: A method and circuits for testing an integrated circuit at functional clock frequency by providing a test controller generating control signals that assure proper latching of test patterns in scan chains at tester frequency and propagation of the test pattern through logic circuits being tested at functional clock frequency.

Abstract: A SCAN test circuit for giving a semiconductor integration circuit a scan test includes a scan enable signal generating device that generates scan enable signals based on a scan enable external input signal, a clock generator that generate launch and capture clocks for collectively detecting a delay malfunction at a practical operation speed, and a controller configured to control the clock generator based on the scan enable signals.

Abstract: A method for configuring IO pads, the method includes determining a current configuration of multiple IO pads of an integrated circuit and whereas the method is characterized by generating multiple boundary scan register words that comprise Configuration information; and repeating the stage of serially writing a certain boundary scan register word to a boundary scan register and outputting the boundary scan register word to multiple IO pad control circuits. A device that includes a core, connected to a boundary scan register, a TAP controller and multiple IO pad circuits, the device is characterized by including a control circuit adapted to determine a current configuration of the IO pads, to generate multiple boundary scan register words that comprise configuration information; and to control a repetition of: writing a certain boundary scan register word to the boundary scan register and outputting the boundary scan register word to multiple IO pad control circuits.

Abstract: Systems and methods for testing a circuit are provided. In one example, a sequential device for use in a scan chain is described. The sequential device may include a scan input, a scan output and a functional data output. The functional data output may be coupled to the scan input and to the scan output. The functional data output may be coupled to the scan output via a delay buffer.

Abstract: A system for testing a circuit. The system comprises a first circuit mounted on an embedded first circuit board and a test circuit mounted on the embedded first circuit board. The system further comprises a second circuit board on the first circuit board, the second circuit board including a second circuit and a test device external to the first and second circuit board. The test circuit is effective to send at least one first test signal from the test circuit to the first circuit, receive a first response of the at least one first test signal from the first circuit, and forward the first response to the test device.

Abstract: An integrated circuit containing memory includes IEEE 1149.1 (JTAG) controlled self-repair system that permits permanent repair of the memory after the integrated circuit has been packaged. The JTAG controlled self-repair system allows a user to direct circuitry to blow fuses using an externally supplied voltage to electrically couple or isolate components to permanently repair a memory location with JTAG standard TMS and TCK signals. The system may optionally sequentially repair more than one memory location using a repair sequencer.

Abstract: An IC includes an IEEE 1149.1 standard test access port (TAP) interface and an additional Off-Chip TAP interface. The Off-Chip TAP interface connects to the TAP of another IC. The Off Chip TAP interface can be selected by a TAP Linking Module on the IC.