Abstract: A method and circuit for collecting memory failure information on-chip and unloading the information in real time while performing a test of memory embedded in a circuit comprises, for each column or row of a memory under test, testing each memory location of the column or row according to a memory test algorithm under control of a first clock, selectively generating a failure summary on-circuit while testing each column or row of the memory; and transferring the failure summary from the circuit under control of a second clock within the time required to test the next column or row, if any, of the memory under test.

Abstract: A self-repair circuit for a semiconductor memory provides input and output test selectors coupled to respective data bit group inputs and outputs, respectively and input and output repair selectors coupled between the input and output test selectors and functional inputs and functional outputs, respectively. This arrangement allows all data bit groups to be tested in one pass and all test and repair selector circuitry to be tested.

Abstract: A program product for use in generating test benches for verifying test structures embedded in a circuit, comprises a verification specification processor for parsing a verification specification containing test specifications for selected test structures and a test bench generator for each of one or more types of embedded test structures, each test bench generator being operable to process a test structure specification of a test structure of a corresponding test structure type and generate a test bench using data contained in said test specifications of said verification specification, data contained in said test structure specification and data contained in a test connection specification.

Abstract: A circuit and method are described in which a DC voltage or current is connected to a high frequency, AC-coupled signal path between a transmitter and a receiver, and the bit error rate of the data transmission is tested while applying an altered bias voltage to the received signal. The bias voltage can be connected via a resistor, inductor or transistors. The transmitted signal is attenuated resistively, and a load capacitance is applied whose value causes digital transition times to exceed one unit interval. An intended application is testing of an integrated circuit, serializer/deserializer (serdes) operating above 1 GHz.

Abstract: A method for accurately delivering a voltage to a circuit node of an integrated circuit having analog buses and transmission gates selectively connecting the circuit node to the buses, comprises sensing the voltage on the circuit node via a first of the buses under control of a first periodic signal; applying a first stimulus voltage to the circuit node via a second bus under control of a second periodic signal; and applying a second stimulus voltage to the circuit node under control of a third periodic signal which is inverted with respect to the second periodic signal so that the circuit node is driven alternately to the first stimulus voltage and to the second stimulus voltage.

Abstract: A method and program product for verifying a logic design for proper operation of tri-state buses in the design, comprises, for each bus in the circuit design, determining the smallest cut set, a min-cut, of the logic controlling the bus, performing an exhaustive analysis on a min-cut set of logic, and performing a full exhaustive analysis of the bus when the exhaustive analysis on the min-cut set of logic is inconclusive. In a preferred embodiment, prior to performing the min-cut set analysis, implication based conflict-free and float-free analyses are performed on the bus.

Abstract: A method of designing integrated circuits having an hierarchical structure for quiescent current testing, and the circuit which results therefrom is disclosed. The method comprises analyzing each of one or more selected hierarchical blocks independently of other selected blocks identify any circuit states of each block which could result in elevated quiescent current levels during quiescent current testing of the circuit, the analysis beginning with blocks at a lowest level of hierarchy and proceeding in sequence through each level of design hierarchy to a highest level of hierarchy containing a top-level block; and calculating a fault coverage for each selected block.

Abstract: A method of designing a circuit having at least one hierarchical block which requires block specific test patterns to facilitate quiescent current testing of the circuit, comprises, for each block, configuring the block and any embedded blocks located one level down in design hierarchy in quiescent current test mode in which input and output peripheral memory elements are configured in internal test mode and in external test mode, respectively; generating quiescent current test patterns which do not result in elevated quiescent current levels and which include a bit for all memory elements in the block and for any peripheral memory elements in any embedded blocks located one level down in design hierarchy; and, if the block contains embedded blocks, synchronizing the test pattern with a corresponding test pattern generated for embedded blocks so that test patterns loaded in scan chains in the block are consistent with test patterns loaded in scan chains in said embedded blocks.

Abstract: A memory test controller comprises a test instruction register array for storing a plurality of test instructions, each register having instruction fields for storing instruction data specifying operations to be performed on the memory array, a repeat module for repeating a group of one or more of the test instructions with modified data, the repeat module including storage means for storing instruction field modification data; and each register of the test instruction register array including an instruction field for enabling or disabling the repeat module.

Abstract: In a circuit with multiple Test Access Port (TAP) interfaces, the TAPs are arranged into groups, with secondary TAPs in one or more groups and a master TAP in another group, the master TAP having an instruction register with bits for storing a group selection code; a Test Data Output (TDO) circuit responsive to the group selection code connects the group TDO of one of the groups to the circuit TDO; and, for each secondary TAP group, a group Test Data Input (TDI) circuit responsive to a shift state signal for selectively connecting the group TDI to the circuit TDI or to the output of a padding register having its input connected to the circuit TDI, and its output connected to an input of the group TDI circuit; and a group TMS circuit responsive to a predetermined TAP selection code associated with the group for producing a group TMS signal for each TAP in the group.

Abstract: A method for at-speed scan testing of circuits having scannable memory elements which source multi-cycle paths having propagation delays that are longer than the period of a system clock used during normal operation comprises loading a test stimulus into the scannable memory elements; performing a capture operation, including configuring in capture mode throughout the capture operation, non-source memory elements and multi-cycle path source memory elements which have a predetermined maximum capture clock rate which is the same as or higher than the clock rate of the capture clock; and configuring in a hold mode during all but the last cycle of the capture operation and in capture mode for the last cycle, source memory elements which have a predetermined maximum capture clock rate which is lower than the clock rate of the capture clock; applying at least two clock cycles of the capture clock; and unloading test response data captured by said scannable memory elements.

Abstract: A test access circuit (TAC) for use in controlling test resources including child test access circuits (TACs) and/or test controllers, in an integrated circuit, comprises an enable input for enabling or disabling access to the test resources, a test port associated with each test resource, each test port including a test port enable output for connection to an enable input of an associated test resource; and an input for receiving a serial output of the associated test resource; and a selector for selecting a test resource for communication therewith.

Abstract: A method of masking corrupt bits in test response pattern scan chains in an integrated circuit, comprising loading and applying a set of test patterns in the scan chains so as to obtain corresponding test response patterns; and masking bits of the test response patterns located in scan chains identified by a chain mask and at a position identified by a position mask.

Abstract: A method of collecting failure information when testing a memory comprises performing a test of the memory according to a test algorithm, and, while performing the test, counting failure events which occur after a predetermined number of masked events; stopping the test upon occurrence of a stopping criterion which comprises one of occurrence of a first failure event, a change of a test operation; a change of a memory column address; a change of a memory row address; a change of a memory bank address; and a change of a test algorithm phase; and storing failure information.

Abstract: A sign-off method for use in verifying of embedded test structures in a circuit design extracts a description of all embedded test structures from a circuit description to create a test connection map file, and verifies the connections of the test structures to circuit pins or nets, creates verification configuration files for use, in performing a sign-off verification of the circuit, for a circuit containing logic test structures, verifies that each logic test structure complies with logic test design rules and creates logic test vectors and a reference signature, performs a formal verification and a static timing analysis of the circuit, generates a sign-off simulation test bench for each test structure using the verification configuration files and the test connection map file, executes the test benches to simulate all test structures in the circuit; and creates manufacturing test patterns.

Abstract: A method for testing an integrated circuit (IC) for open defects in a printed wire connected to an IC pin of the IC, the method includes measuring the capacitance of the IC pin; comparing the value of the measured capacitance to an expected IC pin capacitance value for the pin unconnected, and determining that an open defect exists proximate the pin when the measured capacitance is less than a predetermined value based on the expected IC pin capacitance value.

Abstract: A method for sequentially accessing circuit nodes in an IEEE 1149.

Abstract: An embedded test, chip design utility is an ease-of-use utility for assisting a circuit designer in quickly implementing a circuit embedded test design flow. Using the utility, a designer transforms a design netlist to include embedded test structures. The utility automatically builds a workspace containing a predetermined repository structure and design environment, generates control files for executing design automation tools that operate within the design flow, and encapsulates the data so as to be self-contained and easily transferable to other design teams.

Abstract: A method of scan testing an integrated circuit to provide real time identification of a block of test patterns having at least one failing test pattern comprises performing a number of test operations and storing a test response signature corresponding to each block of test patterns into a signature register; replacing the test response signature in the signature register with a test block expected signature; identifying the block as a failing test block when the test response signature is different from the test block expected signature; and repeating preceding steps until the test is complete.

Abstract: One aspect of the invention is generally defined as a method of designing an integrated circuit for distributing test clock signals to embedded cores having at least one core functional clock input, the method comprising, for each core, providing a clock gating circuit for selectively disabling a core functional clock signal applied to a core primary clock input; and providing a core clock selection circuit for each secondary core functional clock input for selecting one of a core functional clock signal output by the gating circuit and a core test clock signal and applying a selected signal to the each secondary core functional clock input.