Abstract: A method and circuit for measuring a time interval between transitions of periodic signals at nodes of a circuit-under-test (CUT), the signals having a periodic clock frequency, the method includes periodically latching a digital value of a first periodic signal at edges of an undersampling clock, simultaneously periodically latching a digital value of a second periodic signal at edges of the undersampling clock, combining the latched digital values of the first and second periodic signals to produce a combined output whose duty cycle is proportional to the time interval between a median edge of latched digital values of the first periodic signal and a median edge of latched digital values of the second periodic signal; and counting the number of undersampling clock cycles in which the combined output is a predetermined logic value within a predetermined time interval whereat the number is proportional to a time interval between a transition of the first periodic signal and a transition of the second periodic

Abstract: A clocking method for at-speed scan testing for delay defects in cross-domain paths of interacting synchronous clock domains in a scan circuit, each path originating from a source memory element in one of the domains and terminating at a destination memory element in another of the domains and comprises selectively aligning either a capture edge or a launch edge of the clock of each domain with a corresponding edge of at least one other domain of the interacting synchronous clock domains to determine the cross-domain paths to be tested between a source domain and a destination domain; clocking memory elements in each domain at respective domain clock rates to launch signal transitions from source memory elements in source domains; and for each pair of interacting clock domains under test, capturing, in the destination domain, circuit responses to signal transitions launched along paths originating from the source domain and selectively disabling capturing, in the source domain, of circuit responses to signal

Abstract: A circuit and a method are provided for testing the enable function of Boundary Scan Register bits that control the driver of unconnected I/O pins of an 1149.1-compliant IC during the IC's reduced pin-count access manufacturing test, and to test the connections to these pins during the test of a circuit board containing the IC, without causing excessive current if a pin is inadvertently short circuited.

Abstract: A method of fault diagnosis of integrated circuits having failing test vectors with observed fault effects using fault candidate fault-effects obtained by simulation of a set of test vectors, comprises determining a fault candidate diagnostic measure for each fault candidate, the fault candidate diagnostic measure having a fault candidate match metric, an observed fault effect mismatch metric and a fault candidate excitation metric, ranking fault candidates in decreasing diagnostic measure order; and identifying fault candidate(s) having the highest diagnostic measure as the most likely cause of observed fault effects.

Abstract: A method and circuit for repairing a memory array having one or more memory segments each having one spare column and a predetermined number of spare rows common to all segments, the method comprises, while testing the memory array for failures, generating an equal number of unique segment repair solutions for each segment with each segment repair solution including one defective column address, if any, and a number of defective row addresses, if any, corresponding to the predetermined number of spare rows; and, after completing testing, analyzing all segment repair solution combinations consisting of one segment repair solution selected from each segment; and identifying the best segment repair solution combination of combinations having a number of different defective row addresses which is less than or equal to the predetermined number of spare rows.

Abstract: A method and circuit for measuring a statistical value of jitter for a data signal having a data rate fD, comprises digitally sampling the data signal at a sampling rate, fS, to produce sampled logic values, where fD/fS is a predetermined non-integer ratio; and analyzing the sampled values to deduce a statistical value of the jitter.

Abstract: A boundary scan cell for use in a circuit having a boundary scan shift register (BSSR) having boundary scan cells associated with pins of the circuit, the cell having a single-bit shift register element and an associated update latch, comprises a logic circuit for controlling the logic state of an associated pin, analog switches connecting the associated pin to analog test buses, and logic circuitry for selectively configuring the cell in a parametric test mode in which the cell shift register element controls the analog switches, and in a digital test mode in which the cell shift register element controls the logic state of the associated pin.

Abstract: A test clock controller for generating a test clock signal for scan chains in integrated circuits having one or more clock domains, comprises a shift clock controller for generating a shift clock signal for use in loading test patterns into scan chains in the clock domains and for unloading a test response patterns from the scan chains and for generating a burst phase signal after loading a test pattern; and a burst clock controller associated with each of one or more clock domains and responsive to a burst phase signal for generating a burst of clock pulses derived from a respective reference clocks and including a first group of burst clock pulses having a selected reduced frequency relative to the reference clock and a second group of burst clock pulses having a frequency corresponding to that of the reference clock.

Abstract: A method of testing write enable lines of random access memory having at least one word having one or more write enable inputs for controlling write operations in the word, comprises, for a selected memory address, shifting a series of test bits through an addressed word via a first data input to the word, and for each test bit, performing a write operation to the word using a write enable test input derived from data outputs of the word or from a test write enable signal applied concurrently to each write enable input; and, after each write operation, comparing a last bit of the word against an expected value to determine whether there exists a defect in a write enable line.

Abstract: A software and hardware system and an associated methodology provides ATE-independent go/no-go testing as well as advanced failure diagnosis of integrated circuits for silicon debug, process characterization, production (volume) testing, and system diagnosis comprises an embedded test architecture designed within an integrated circuit; means for seamlessly transferring information between the integrated circuit and its external environment; and an external environment that effectuates the seamless transfer for the user to perform relevant test and diagnosis.