107 results about "Test pattern generators" patented technology

A scan-based BIST architecture for detecting path-delay faults in a sequential circuit converted to a combinational circuit or a less complex sequential circuit including a combinational portion and a plurality of scan flip-flops. The BIST structure includes a test pattern generator for generating two test patterns and a controller for generating a clock signal and an extended scan mode signal which is held high for two clock cycles while the output response of the combinational portion to the first and second test vectors is latched into the scan flip-flops in order to detect a signal transition. The invention is further directed to a method for detection of path-delay faults using this scan-based BIST architecture. To improve the fault coverage for path-delay faults, observation points may be inserted at the inputs of selected scan flip-flops. A predetermined number of scan flip-flops having the highest activation frequency are selected as the observation points.

There is disclosed a semiconductor integrated circuit comprising a logic BIST circuit which includes a test pattern generator and test result compressor and which performs a built-in self test (logic BIST) of a logic circuit, a pattern counter which counts test patterns during the logic BIST, an expected value comparison circuit which compares a compressed value output of the test result compressor with an expected value input from an external tester for each test pattern and which outputs a failure flag at a mismatch detection time, an external terminal which outputs the failure flag from the LSI, and an external terminal which outputs from the LSI a pattern count signal at a time when the pattern counter receives the failure flag.

A graphical user interface (GUI) provides a design engineer the capability of automatically inserting scan logic and test logic into a design. The graphical user interface includes a scan insertion option for a design engineer to invoke a scan insertion tool to check the design for testability. The graphical user interface also permits the design engineer to invoke a test generation tool such as an automatic test pattern generator (ATPG) tool to check the design for fault coverage. The graphical user interface, which can serve as a front end for a design framework, enables a design engineer to efficiently increase testability while still in a design phase.

An electronic system with a self-test function has a pseudo-random test pattern generator that serially generates data constituting a pseudo-random test pattern, and stores a 1-bit shifted pseudo-random test pattern obtained by shifting the pseudo-random test pattern by one bit. When a scan-path circuit supplies the pseudo-random test pattern to a tested circuit which carries out an operation based on the pseudo-random test pattern, and then loads an operation result of the tested circuit, the 1-bit shifted pseudo-random test pattern is supplied to the tested circuit as the next pseudo-random test pattern. This makes it possible to solve a problem of a conventional electronic system in that it takes a long time to evaluate the operation results of the tested circuit because it takes at least (1+n)xm clock cycles, where m is the number of pseudo-random test patterns supplied to the tested circuit and n is the number of stages of the scan-path circuit.

The invention relates to a correction method and device, in particular to an automatic gamma and white balance correction method and a device for a display device. The automatic gamma and white balance correction device comprises a display device, a color analysis meter, a PC (Personal Computer) and a test pattern generator which are sequentially connected electrically; the test pattern generator is electrically connected with the display device through a driving IC (Integrated Circuit). According to the automatic gamma and white balance correction device, whether the quadratic sum of difference between luminance values under different gray levels and target luminance values satisfies an error range or not is judged, correction is finished after solidification of gamma register parameters in a gamma register of the driving IC, the gamma register parameters are modified if not, and recalibration is performed until the quadratic sum of the difference between the luminance values and the targeted luminance values satisfies the error range; a calibration result is automatically judged after calibration of gamma and white balance and the calibration result is not influenced by subjective judgment of tested person.

The present invention is generally directed to an improved automatic test pattern generator for generating test patterns that are used by an integrated circuit testing device. In accordance with one aspect of the invention, a method is provided for generating a set of test vectors for testing an integrated circuit, each test vector of the set of test vectors containing a plurality of bits defining test inputs for the integrated circuit. The method includes the steps of defining a list of faults for the integrated circuit, and generating at least one test vector that defines values for those inputs necessary to detect at least one target fault selected from the list of faults, the values comprising only a portion of the bits of the at least one test vector, wherein a remainder of the bits in the at least one test vector are unspecified bit positions. The method further includes the step of setting the values of a plurality of the unspecified bit positions using a non-random filling methodology.

A communication system includes first and second independently clocked devices, comprising, for each device, a transmitter and a receiver connected to each other in a crossed way in correspondence of an inter-chip communication channel. The communication system further comprises a synchronizer in turn including at least a first and a second synchronization block, having respective input terminals connected to the receivers and respective output terminals connected to the transmitters and comprising at least: a test pattern generator that generates a programmable test pattern signal; a pattern detector to check a matching between stored and received test pattern signals and thus lock corresponding clock phases of the synchronization blocks in case of positive result of this check; and a delay block able to change the clock phases until a synchronized condition of the synchronization blocks is verified, this synchronized condition corresponding to a matching between stored and received test pattern signals.

A semiconductor integrated circuit test method which reduces the required data volume for testing and efficiently detects faults in a circuit to be tested, the method comprising means 110 to generate identical pattern sequences repeatedly and means 120 to control flipped bits in pattern sequences, in order to generate neighborhood pattern sequences and use the neighborhood patterns to test the circuit under test 130. The neighborhood patterns include, in whole or in part, such pattern sequences as ones without flipped bits, ones with all or some flipped bits in one pattern and ones with all or some flipped bits in consecutive patterns or patterns at regular intervals, the interval being equivalent to a given number of patterns. Because a test pattern generator is provided independently of the circuit to be tested, the problem of a prolonged design period can be eliminated, a loss in the operating speed of the circuit under test is minimized and a high fault coverage can be achieved with less hardware overhead and a smaller volume of test data.

The invention discloses a built-in self-test structure and method for an on-chip network resource node storage device. The built-in self-test structure comprises a built-in self-test (BIST) controller arranged on a field programmable gate array (FPGA) chip, a resource network interface and a BIST interface which are embedded into corresponding routers, a test pattern generator and a test response analyzer, wherein the BIST controller is connected with external test equipment through an external interface. The built-in self-test method comprises the following steps that: the external test equipment sends an instruction start test program to the BIST controller; the BIST controller sends an enabling signal and a state selection signal to each test module according to a March C+ test algorithm program, performs read-write operation on each address of a static random access memory (SRAM) under each test state, and stops sending the signals if failures are found out. A test result is sent to the external test equipment. According to the built-in self-test structure and method, the test time is reduced by 50 percent; a routing network of a network operation center (NoC) is reused as a test data route; data transmission is reliable and safe; a chip area is low in expense; the failure coverage rate is high.

Techniques for generating a test set for hard to detect faults is disclosed. A set of hard to detect faults is identified. A test set for the hard to detect faults is generated by using an improved automatic test pattern generator. The improved automatic test pattern generator is adapted to consider hardware overhead and test sequence lengths, the hardware overheads being incurred when each new testcube is added to the test set. Parallel and serial type test per scan built-in self test circuits designed and adapted to use the disclosed improved automatic test pattern generator are also disclosed.

Disclosed is a method of testing memory, comprising providing one or more semiconductor wafers having one or more semiconductor chips thereon, each said chip comprising one or more memory cells, providing a programmable testing apparatus comprising at least one test pattern generators and a test bed adapted to receive said one or more wafers in communicative contact so as to address individual memory cells, chips, and wafers and transmit information thereto and receive information therefrom, receiving one or more test commands, constructing a test sequence of one or more commanded tests from said test commands, constructing at least one header comprising location information for each said wafer, chip and memory cell, testing said memory cells with a test pattern generated by said test pattern generator, collecting the results of said testing and passing them to a display device, passing said location information to said display device, constructing and displaying a graphical representation of said test results using said location information.