Motorola Corporation

Advanced Micro Devices Corporation

Globalfoundries Inc.

Grady L Giles

Joel Thornton Irby

Jesse R Wilson

Matthew D Pressly

Alfred Larry Crouch

Thomas K Johnston

William Clayton Bruce, Jr

Stephen Victor Kosonocky

John J Vaglica

Atchyuth Gorti

Bernard J Pappert

Robert Bradford Cohen

William Daune Atwell

Richard B Reis

Floyd L Dankert

Yui K Ho

Timothy J Wood

Daniel T Marquette

William D Atwell, Jr

Gregory A Constant

Michael Alan Mateja

Alexander W Schaefer

Clark Gilson Shepard

James A Wingfield

Terry V Hulett

John Mark Boyer

Amy M Novak

Kerry Ken Kanbe

Brian Hoang

Jason E Doege

Lee Allen Corley

Odis Dale Amason, Jr

An integrated circuit includes a latch array including a plurality of latches logically configured in rows and columns, a plurality of repair latches operatively coupled to the plurality of latches and latch array built in self-test and repair logic (LABISTRL) coupled to the plurality of latches. In some implementations the LABISTRL configures latches in the array as one or more column serial test shift register, detects one or more defective latches of the plurality of latches based on applied test data, and selects at least one repair latch in response to detection of at least one defective latch.

Repairable latch array

Some embodiments of a power supply monitor include a measurement circuit to measure a voltage provided to the power supply monitor, a comparator to compare the voltage to a predetermined voltage threshold, and an interface to provide, during a scan test of a processing device including the power supply monitor, a fault signal in response to the voltage being below the voltage threshold. Some embodiments of a method include providing a first test pattern to one or more power supply monitors associated with one or more circuit blocks in the processing device and capturing a first result generated by the power supply monitor(s) based on the first test pattern. The first result indicates whether a voltage provided to the circuit block(s) is below a voltage threshold.

Power supply monitor for detecting faults during scan testing

A test circuit for a functional circuit includes a scan chain coupled to the functional circuit, and a controller coupled to the scan chain, for controlling the scan chain to scan a test pattern into the scan chain, and subsequently and repetitively for a multiple number of times launch the test pattern to the functional circuit, capture test data into the scan chain, and restore the test pattern in the scan chain for subsequent launch.

Test circuit having scan warm-up

A processor having a pipelined test access mechanism (TAM). The processor includes a plurality of processor cores. Each of the processor cores includes a scan chain including plurality of serially-coupled scan elements. The processor further includes the pipelined TAM, which includes a plurality of pipeline stages each corresponding to one of the plurality of processor cores. The pipelined TAM includes a command channel, a scan data input (SDI) channel, a scan data output (SDO) channel, and a compare channel. Each pipeline stage is operable to convey commands to its corresponding processor core via the command channel, to convey scan input data to its corresponding processor core via the SDI channel, to receive scan output data conveyed from the corresponding processor core to the SDO channel and the compare channel, and convey compare data downstream via the compare channel, wherein the compare data is based on the scan output data.

Test access mechanism for multi-core processor or other integrated circuit

An integrated circuit. The integrated circuit includes a plurality of logic circuits. The integrated circuit further includes a scan chain including a plurality of scan elements coupled in series, wherein the scan chain is configured to load stimulus data to be applied to the logic circuits for testing. The scan chain is further configured to capture data subsequent to applying the stimulus data. The integrated circuit also includes an embedded memory having a read port, wherein the read port is coupled to one or more of the plurality of logic circuits via a read path. The embedded memory includes a virtual entry having a plurality of scan-controllable storage elements. During testing, the virtual entry is operable to apply transition data to the read path in order to cause logic state transitions in the one or more logic circuits in the read path.

Apparatus for testing embedded memory read paths

A BIST controller (,) and methodology uses the DRAM controller (,) refresh signals to test the data retention characteristics of a DRAM memory array (,). The BIST controller blocks a fraction of the refresh cycles generated by the DRAM controller to provide a margin of confidence above the DRAM's specified retention time. The BIST controller is especially suited to embedded applications in which access to the memory is indirect and to applications in which the memory system is modular. The invention may also be used to characterize the actual retention time of a particular DRAM allowing the system to optimize the DRAM's refresh interval.

Method and apparatus for verifying and characterizing data retention time in a DRAM using built-in test circuitry

A method and apparatus that improves either power savings and/or DRAM system access bandwidth in an embedded DRAM device. The apparatus (200, 800, or 900) contains embedded DRAM memory devices (212, 802, or 902) which require refresh operations in order to retain data. As the memory devices (212, 802, or 902) are accessed by read and write system operations and by refresh operations, a set of history bits (204, 808, 904) are continually updated to indicate a level of freshness for the charge stored in various DRAM memory rows. When scheduled refresh opportunities arrive for each memory row in the embedded DRAM devices, the history bits (204, 808, 904) are accessed to determine if the refresh operation of a row of memory should be performed or if the refresh operation should be postponed until a subsequent refresh time period.

Method and apparatus for leveraging history bits to optimize memory

A method of memory array testing that detects defects which are sensitive to environmental conditions. A repair signature is generated reflecting the repair state of the memory. A memory device is rejected if there is a change in the repair signature of the memory array over the operating range of the device. In one embodiment, an integrated circuit includes a memory array, spare memory elements for repairing defective locations of the memory array, a built-in self-test (BIST) circuit for detecting faults in the memory array, a built-in self-repair (BISR) circuit for causing the failed memory location of the memory array to be replaced with a spare memory element, and a signature generator where the signature is based on a compression of addresses corresponding to failed memory locations, wherein the signature is used to determine that a repair result of the memory array is invariant over different environmental conditions.

Method and apparatus for testing an integrated memory device

An integrated circuit contains customer specified logic (12), an embedded core (14), and a plurality of speed path test cells (16 and 18). Once the core (14) is embedded within an integrated circuit (10), not all of the input and output terminals of the embedded core are available at external terminals of the integrated circuit (10). Therefore, the wrapper speed path test cells (16 and 18) are provided. The cell (16) contains two flip-flops (20 and 22) which can be used to launch logic transitions into the embedded core (14) to perform two clock speed path testing. The cell (18) contains flip-flops (26 and 28) which can perform a speed path launch operations to a customer specified logic (12). The cell (16) can perform speed path capture operations for the customer specified logic (12) whereas the cell (18) can perform speed path capture operations for the embedded core (14).

Wrapper cell architecture for path delay testing of embedded core

A method and implementation for providing an improved testable design for an integrated circuit (IC) device. The integrated circuit includes a functional path for the implementation of a functional specification as well as a testing path for testing the timing specifications for the integrated circuit. Input switching devices are connected between input terminals of the IC and inputs to sequential circuit elements, for example flip-flop devices, in the IC. Similarly, output switching devices are connected between outputs of the flip-flop devices and output terminals of the IC. The switching devices are selectively operable to alternately connect the flip-flop devices into either a functional IC path for providing functional output signals during functional cycles, or into a testing IC path for providing testing output signals indicative of timing points throughout the IC during testing cycles. The IC is also operable to selectively disable tristate bus drivers during the testing cycles. The switching devices are arranged such that a single output terminal of the IC may be selectively used to provide both functional and testing output signals.

Scan based testing of an integrated circuit for compliance with timing

Wrapper cells (16 and 18) are coupled to inputs and outputs of an embedded core (14) within an integrated circuit (10). The wrapper cells (16 and 18) are used to test timing specifications of the embedded core after the embedded core has been integrated on-chip with other peripheral logic (12). In order to accurately measure the timing specifications, test circuits (FIGS. 6-8) are formed on chip with the wrapper where the test circuits are used to measure clock skew a like internal integrated circuit (IC) parameters. The clock skew and other measured internal IC parameters are used to accurately test the timing specification of the embedded core with reduced uncertainty.

Timing apparatus and timing method for wrapper cell speed path testing

A method and apparatus for shifting data in an array of storage elements (22-37) in a data processing system (10). In one form, the present invention uses multiplexer (MUX) logic (38) and Shift Control signals to selectively couple storage elements (22-37) to latches (39-42). In this manner, data values can be serially scanned into and out of the array for test purposes without requiring a duplicate set of latches. The MUX logic 38 couples one storage element (22-37) to each latch (39-42). Then MUX logic 38 decouples those storage elements (22-37). Next, MUX logic 38 couples an adjacent storage element (22-37) to each latch (39-42). In this manner, the storage elements (22-37) in one row and the latches (39-42) mimic the functionality of a shift register.

Method and apparatus for shifting data in an array of storage elements

An apparatus (10) indicates a duplication of information stored in a content addressable memory (CAM 12) system at the time the information is written to the system. In the CAM system, Match line signals (Match 0-Match (N-1) are asserted when information being written to a predetermined row is identical to information previously stored in the system. However, the Match line signal associated with the predetermined row is disabled by a predetermined transistor (14, 16, 18, 20) when the row is written. Because information is simultaneously presented in parallel to other rows in the CAM system, a Match line signal is asserted if the information currently written to the predetermined row is identical to information previously written to another row in the CAM system. Any asserted Match line signal which was not disabled indicates to the user of the CAM system that two or more entries are identical in the CAM array.

Method and apparatus for indicating a duplication of entries in a

A toggle-free scan flip-flop (TFSFF) is provided which is designed for use during a test mode scan operation. The toggle-free scan flip-flop has the capability of not toggling its parallel output during test mode scan operation. The TFSFF uses a master latch, which is controlled by a scan multiplexor, to selectively update two alternate slave latches. Switching logic controls the determination of which alternate slave latch is updated with the incoming data signal. An existent scan enable (SE) signal controls the switching logic, and thus, the TFSFF design requires no additional control signals for its operation. During the scan test mode, the data is clocked through the TFSFF from a Scan-Data-In terminal, and out the Scan-Data-Out terminal, without affecting the system data output Q. The shift sequence is followed by a capture interval, during which the Q output is automatically updated with the desired data to test the target logic. Thus, the logic under test is not affected by the loading of the scan test vector, since the parallel system output Q of the TFSFF does not toggle during the shifting sequence.

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Austin, TX, United States of America

Grady L Giles