Abstract: A test circuit is disclosed for testing embedded synchronous memories. A BIST controller is used to address the memory and provide reference data that is compared to the memory output. Pipeline registers are used to allow the BIST controller to perform reads and/or writes during every clock cycle. In one aspect, the BIST controller includes a reference data circuit that stores or generates data for comparison to the memory output. A pipeline register is positioned before the reference data circuit or between the reference data circuit and compare circuitry. Additional pipeline registers may be positioned between a compare capture circuit and the compare circuitry. The pipeline registers free the BIST controller from having to wait for a read to complete before starting the next read or write. To reduce the number of pipeline registers needed, a negative-edge BIST controller can be used with a positive-edge memory or vice versa.

Abstract: Methods and apparatus for analyzing memory defects in an embedded memory are described. According to certain embodiments, the analysis can be performed “at-speed” and can be used to analyze multi-bit failures in words of a word-oriented memory. According to some embodiments, the analysis comprises updating a record of column defects not repaired by spare rows as the memory is being tested. The record can be evaluated after a test to determine whether a repair strategy can successfully repair a memory-under-test.

Abstract: Various new and non-obvious apparatus and methods for testing embedded memories in an integrated circuit are disclosed. One of the disclosed embodiments is an apparatus for testing an embedded memory in an integrated circuit. This exemplary embodiment comprises input logic that includes one or more memory-input paths coupled to respective memory inputs of the embedded memory, a memory built-in self-test (MBIST) controller, and at least one scan cell coupled between the input logic and the MBIST controller. The scan cell of this embodiment is selectively operable in a memory-test mode and a system mode. In memory-test mode, the scan cell can apply memory-test data to the memory inputs along the memory-input paths of the integrated circuit. Any of the disclosed apparatus can be designed, simulated, and/or verified (and any of the disclosed methods can be performed) in a computer-executed application, such as an electronic-design-automation (“EDA”) software tool.

Abstract: Methods are described for scheduling the concurrent testing of multiple cores embedded in an integrated circuit. Test scheduling is performed by formulating the problem as a bin-packing problem and using a modified two-dimensional or three-dimensional bin-packing heuristic. The tests of multiple cores are represented as functions of at least the integrated circuit pins used to test the core and the core test time. The representations may include a third dimension of peak power required to test the core. The test schedule is represented as a bin having dimensions of at least integrated circuit pins and integrated circuit test time. The bin may include a third dimension of peak power. The scheduling of the multiple cores is accomplished by fitting the multiple core test representations into the bin.

Abstract: A computer-implemented method and apparatus for creating a testable circuit design that includes one or more embedded cores. The method includes identifying an embedded core within the circuit design; associating certain pins of the embedded core with pins of the circuit design; and inserting into the circuit design access circuitry coupling the certain connection pins of the embedded core to the associated pins of the circuit design. The method further includes providing test vectors for the embedded core; and generating test vectors for the circuit design by mapping the core test vectors applicable to the certain pins of the embedded core to the associated pins of the circuit design. The cores within the circuit design can then be tested after manufacture by applying the design test vectors to the circuit design.

Abstract: A test circuit is disclosed for testing embedded synchronous memories. A BIST controller is used to address the memory and provide reference data that is compared to the memory output. Pipeline registers are used to allow the BIST controller to perform reads and/or writes during every clock cycle. In one aspect, the BIST controller includes a reference data circuit that stores or generates data for comparison to the memory output. A pipeline register is positioned before the reference data circuit or between the reference data circuit and compare circuitry. Additional pipeline registers may be positioned between a compare capture circuit and the compare circuitry. The pipeline registers free the BIST controller from having to wait for a read to complete before starting the next read or write. To reduce the number of pipeline registers needed, a negative-edge BIST controller can be used with a positive-edge memory or vice versa.