Certain aspects of the present disclosure provide a circuit for testing processor cores. For example, certain aspects provide a circuit having a deserializer having at least one input coupled to at least one input node of the circuit and having a first plurality of outputs, a plurality of processor cores having inputs coupled to the first plurality of outputs of the deserializer, and a serializer having inputs coupled to a second plurality of outputs of the plurality of processor cores.

A number of embodiments include an apparatus comprising a memory array including a first memory bank and a second memory bank and a serializer/de-serializer coupled to the first memory bank and the second memory bank. The serializer/de-serializer may be configured to receive a scan vector from the first memory bank, send the scan vector to a device under test, receive scan test responses from the device under test, and send the scan test responses to the second memory bank. Scan control logic may be coupled to the serializer/de-serializer and the device under test. The scan control logic may be configured to control operation of the serializer/de-serializer and send a scan chain control signal to the device under test, wherein the scan chain control signal is to initiate performance of a scan chain operation using the scan vector.

A system, apparatus, and method of testing a plurality of test circuits is disclosed that includes inputting experiment data to the plurality of test circuits; applying a control signal to each of the plurality of test circuits to control application of the experiment data to the plurality of test circuits; and shifting the control signal in response to applying the control signal to each of the plurality of test circuits so that a different bit of the control signal is applied to each of the plurality of test circuits. The method in an aspect further comprises reading out a data out signal from each of the plurality of test circuits; and shifting the data out signal in response to reading out the data out signal from each of the plurality of test circuits.

A device test architecture and interface is provided to enable efficient testing embedded cores within devices. The test architecture interfaces to standard IEEE 1500 core test wrappers and provides high test data bandwidth to the wrappers from an external tester. The test architecture includes compare circuits that allow for comparison of test response data to be performed within the device. The test architecture further includes a memory for storing the results of the test response comparisons. The test architecture includes a programmable test controller to allow for various test control operations by simply inputting an instruction to the programmable test controller from the external tester. The test architecture includes a selector circuit for selecting a core for testing. Additional features and embodiments of the device test architectures are also disclosed.

A test pattern is shifted into scan chains in a circuit in a first direction. The scan cells on each of the scan chains are further coupled to corresponding scan cells on two other scan chains in the scan chains such that data bits stored in the scan cells can be shifted circularly in a second direction orthogonal to the first direction based on a control signal. The loaded test pattern is then shifted in the second direction for a number of clock cycles equal to the number of the scan chains. The test pattern is then shifted in the first direction out of the scan chains to generate a chain test result. Faulty scan cell candidates on faulty scan chains may be determined based on part of the chain test result for one of good scan chains

Embodiments include systems and methods for in-system, scan-based device testing using novel narrow-parallel (NarPar) implementations. Embodiments include a virtual automated test environment (VATE) system that can be disposed within the operating environment of an integrated circuit for which scan-based testing is desired (e.g., a chip under test, or CuT). For example, the VATE system is coupled with a service processor and with the CuT via a novel NarPar interface. A sequence controller can drive a narrow set of parallel scan pins on the CuT via the NarPar interface of the VATE system in accordance with an adapted test sequence having bit vector stimulants and expected responses. Responses of the CuT to the bit vector stimulants can be read out and compared to the expected results for scan-based testing of the chip.

Testing of die on wafer is achieved by; (1) providing a tester with the capability of externally communicating JTAG test signals using simultaneously bidirectional transceiver circuitry, (2) providing die on wafer with the capability of externally communicating JTAG test signals using simultaneously bidirectional transceiver circuitry, and (3) providing a connectivity mechanism between the bidirectional transceiver circuitry's of the tester and a selected group or all of the die on wafer for communication of the JTAG signals.

A device test architecture and interface is provided to enable efficient testing embedded cores within devices. The test architecture interfaces to standard IEEE 1500 core test wrappers and provides high test data bandwidth to the wrappers from an external tester. The test architecture includes compare circuits that allow for comparison of test response data to be performed within the device. The test architecture further includes a memory for storing the results of the test response comparisons. The test architecture includes a programmable test controller to allow for various test control operations by simply inputting an instruction to the programmable test controller from the external tester. The test architecture includes a selector circuit for selecting a core for testing. Additional features and embodiments of the device test architectures are also disclosed.

A scan chain for testing a combinatorial logic circuit includes a first scan chain path of flip-flops connected to the combinatorial logic circuit for functional mode operation during runtime of the combinatorial logic circuit. A second scan chain path of flip-flops is also connected to the combinatorial logic circuit and supports both a shift mode and a capture mode. The second scan chain path operates in shift mode while the first scan chain path is connected to the combinatorial logic circuit for functional mode operation. The second scan chain is then connected to the combinatorial logic circuit when run time is interrupted and operates in capture mode to apply the test data to the combinatorial logic circuit.

Implementations described herein relate to a core and interface scan testing. In some implementations, an integrated circuit may include input scan flip-flops (ISFFs) arranged in multiple ISFF stages that include a first ISFF stage and a second ISFF stage. Inputs to the first ISFF stage are connected to inputs of the integrated circuit. Inputs to the second ISFF stage are connected to outputs of a logic component that is connected to outputs of the first ISFF stage. The integrated circuit may include output scan flip-flops (OSFFS) arranged in multiple OSFF stages that include a first OSFF stage and a second OSFF stage. Outputs from the first OSFF stage are connected to outputs of the integrated circuit. Outputs from the second OSFF stage are connected to inputs of a logic component that is connected to inputs of the first OSFF stage. The integrated circuit may include core scan flip flops.