Abstract: A low power scan flip-flop cell includes a multiplexer, a master latch, a scan slave latch and a data slave latch. The master latch is connected to the multiplexer, and used for generating a first latch signal. The scan slave latch is connected to the master latch, and generates a scan output (SO) signal. The data slave latch is connected to the master latch, and generates a Q output depending on a scan enable (SE) input signal and the first latch signal. The Q output is maintained at a predetermined level during scan mode, which eliminates unnecessary switching of combinational logic connected to the scan flip-flop cell and thus reduces power consumption.

Abstract: An optimized JTAG interface is used to access JTAG Tap Domains within an integrated circuit. The interface requires fewer pins than the conventional JTAG interface and is thus more applicable than conventional JTAG interfaces on an integrated circuit where the availability of pins is limited. The interface may be used for a variety of serial communication operations such as, but not limited to, serial communication related integrated circuit test, emulation, debug, and/or trace operations.

Abstract: A testing system includes a computer, a testing circuit board, and a motherboard. The testing circuit board includes a programmable logic device connected to the computer. The programmable logic device includes a predetermined signal. The programmable logic device is used to output an excitation signal to the motherboard. The motherboard is used to generate a back signal according to the excitation signal. The programmable logic device is used to analyze whether the back signal is consistent with the predetermined signal. The computer is used to display a testing result output by the programmable logic device. The disclosure further offers a testing method.

Abstract: A chip applied to a serial transmission system includes an input terminal, a core circuit, an output terminal, a first transmission line, a second transmission line and a spare transmission line, where the input terminal is used to receive an input signal from a source outside the chip, the output terminal is used to output an output signal, the first transmission lines is coupled between the input terminal and the core circuit, the second transmission line is coupled between the core circuit and the output terminal, and the spare transmission line is coupled between the input terminal and the output terminal. When the core circuit cannot process the input terminal normally, the input signal is directly transmitted to the output terminal via the spare transmission line, and the input signal serves as the output signal to be outputted from the output terminal.

Abstract: A processor-implemented method for determining scan compression ratio based on fault density is provided. The processor-implemented method may include calculating, by a processor, a fault density value for each of a plurality of partitions of an integrated circuit. The fault density is computed by the processor based on a ratio of a total number of faults per partition to a total number of flip-flops per partition. The processor-implemented method further includes the processor determining a compression ratio for each of the plurality of partitions based on the fault density value for each of the plurality of partitions and applying the compression ratio to each of the plurality of the partitions of the integrated circuit.

Abstract: An embodiment is directed to extended test coverage of complex multi-clock-domain integrated circuits without forgoing a structured and repeatable standard approach, thus avoiding custom solutions and freeing the designer to implement his RTL code, respecting only generally few mandatory rules identified by the DFT engineer. Such an embodiment is achieved by introducing in the test circuit an embodiment of an additional functional logic circuit block, named “inter-domain on chip clock controller” (icOCC), interfaced with every suitably adapted clock-gating circuit (OCC), of the different clock domains. The icOCC actuates synchronization among the different OCCs that source the test clock signals coming from an external ATE or ATPG tool and from internal at-speed test clock generators to the respective circuitries of the distinct clock domains. Scan structures like the OCCs, scan chain, etc., may be instantiated at gate pre-scan level, with low impact onto the functional RTL code written by the designer.

Abstract: Scan distributor, collector, and controller circuitry connect to the functional inputs and outputs of core circuitry on integrated circuits to provide testing through those functional inputs and outputs. Multiplexer and demultiplexer circuits select between the scan circuitry and the functional inputs and outputs. The core circuitry can also be provided with built-in scan distributor, collector, and controller circuitry to avoid having to add it external of the core circuitry. With appropriately placed built-in scan distributor and collector circuits, connecting together the functional inputs and outputs of the core circuitry also connects together the scan distributor and collector circuitry in each core. This can provide a hierarchy of scan circuitry and reduce the need for separate test interconnects and multiplexers.

Abstract: Testing of an electrical device is achieved by providing a test access mechanism within the device that can receive scan frames from an external tester. The received scan frames contain stimulus data to be applied to circuitry within the device to be tested, a command for enabling a test control operation, and a frame marker bit to indicate the end of the scan frame pattern. The inputting of scan frames can occur continuously and simultaneous with a commanded test control operation.

Abstract: A core circuit that can be connected in a hierarchical manner, and configured to test a multiple circuits is disclosed. The core circuit includes at least one real input for receiving scan-in data for controlling operation of the core circuit. The core circuit further includes an input register coupled to the at least one real input and configured to store data. The core circuit further includes at least one scan chain coupled a subset if registers of the register chain and configured to generate scan-out data representing the presence of faults in an circuit. Furthermore, the core circuit includes at least one control pseudo-output coupled to the input register and configured to route at least a subset of the data to another register chain in the core circuit or to another core circuit.

Abstract: This invention permits selectively bypasses serial scan chains. Constant or low toggle data is directed to the bypassed serial scan chain, thus reducing power consumption. The number and identity of serial scan chains bypassed during a particular test can be changed dynamically dependent upon the semiconductor process variations of a particular integrated circuit. This enables an optimal test to be preformed for integrated circuits having differing semiconductor process variations.

Abstract: A method of sending programming and debug commands, comprises loading control instructions on a processor from an attached tangible, non-transitory computer-readable medium, copying the contents of a program image file by the processor from the computer-readable medium across a bus to a programmable device on the same card as the processor, signaling the programmable device to send an instruction to a configurable logic device (CLD) on the same card as the processor via a debug channel.

Abstract: An architecture for testing a plurality of circuits on an integrated circuit is described. The architecture includes a TAP Linking Module located between test pins on the integrated circuit and 1149.1 Test Access Ports (TAP) of the plurality of circuits to be tested. The TAP Linking Module operates in response to 1149.1 scan operations from a tester connected to the test pins to selectively switch between 1149.1 TAPs to enable test access between the tester and plurality of circuits. The TAP Linking Module's 1149.1 TAP switching operation is based upon augmenting 1149.1 instruction patterns to affix an additional bit or bits of information which is used by the TAP Linking Module for performing the TAP switching operation.

Abstract: Certain embodiments provide a semiconductor integrated circuit comprising: a logic circuit including combination circuits and first flip-flops; plural selectors for respective first flip-flops configured to switch between first paths from the combination circuits and second paths from previous stage flip-flops of the first flip-flops; plural scan chains in the logic circuit, each of the scan chains configured to have the second path activated by the selectors; a pattern generator configured to generate patterns for test for the scan chains; a test control circuit configured to control the pattern generator and the plural selectors, the test control circuit performing self test; and plural setting terminals configured to set logic values individually in a combination of a part of second flip-flops which are representative of a logic pattern and of the first flip-flops in the logic circuit, the setting flip-flops being representative of a logic pattern.

Abstract: A scan circuit includes first scan flip-flops each including a first logic circuit to receive a plurality of control signals in addition to a scan input signal and a data input signal, and second scan flip-flops each including a second logic circuit to receive the plurality of control signals in addition to a scan input signal and a data input signal, wherein the first scan flip-flops and the second scan flip-flops are connected in series, and the plurality of control signals include only a one-bit reset signal and control signals whose purpose is other than an initialization purpose, and wherein the plurality of control signals are set to a predetermined combination of logic values to cause each of the first scan flip-flops to be initialized to “0” by the first logic circuit and each of the second scan flip-flops to be initialized to “1” by the second logic circuit.

Abstract: An address and command port interface selectively enables JTAG TAP domain operations and Trace domain operations within an IC. The port carries TMS and TDI input and TDO output on a single pin and receives a clock signal on a separate pin. The addressable two pin interface loads and updates instructions and data to the TAP domain within the IC. The instruction or data update operations in multiple ICs occur simultaneously. A process transmits data from an addressed target device to a controller using data frames, each data frame comprising a header bit and data bits. The logic level of the header bit is used to start, continue, and stop the data transmission to the controller. A data and clock signal interface between a controller and multiple target devices provides for each target device to be individually addressed and commanded to perform a JTAG or Trace operation.

Abstract: Techniques and mechanisms for evaluating I/O buffer circuits. In an embodiment, test rounds are performed for a device including the I/O buffer circuits, each of the test rounds comprising a respective loop-back test for each of the I/O buffer circuits. Each of the test rounds corresponds to a different respective delay between a transmit clock signal and a receive clock signal. In another embodiment, a first test round indicates a failure condition for at least one I/O buffer circuit and a second test round indicates the failure condition for each of the I/O buffer circuits. Evaluation of the I/O buffer circuits determines whether the device satisfies a test condition, where the determining is based on a difference between the delay corresponding to the first test round and the delay corresponding to the second test round.

Abstract: A reconfigurable device test scheme is provided for making a test of a reconfigurable device with configuration data which is loaded a smaller number of times. A reconfigurable device used herein holds a plurality of configuration data and is capable of instantaneously switching which configuration is implemented thereby. Specifically, one transfer configuration data and one or more test configuration data are previously loaded in a configuration memory of the reconfigurable device, and a test is made while sequentially switching the transfer configuration data and the test configuration data. In this way, the same configuration data need not be reloaded over and over, so that the test can be made with a smaller number of times of loading as compared with before.

Abstract: A method for performing on-chip spatial debugging of a user circuit programmed into a user-programmable integrated circuit includes halting an internal clock driving synchronous logic elements in the integrated circuit and reading the states of all synchronous logic elements programmed into the integrated circuit while the internal clock is halted. An interrupt to an embedded processor in the integrated circuit running a user application can also be generated. The output of at least one synchronous logic element can be forced to a desired state while the internal clock is halted. The clock can then be restarted or stepped.

Abstract: A scan test system and technique compresses CARE bits and X-control input data into PRPG seeds, thereby providing a first compression. The scan test system includes a plurality of compressor and decompressor structures (CODECs). Each block of the design includes at least one CODEC. An instruction decode unit (IDU) receives scan inputs and determines whether a seed extracted from the scan inputs is broadcast loaded in the CODECs, multicast loaded in a subset of the CODECs, or individual loaded in a single CODEC. This sharing of seeds, exploits the hierarchical nature of large designs with many PRPGs, provides a second compression. Results on large industrial designs demonstrate significant data and cycle compression increases while maintaining test coverage, diagnosability, and performance.

Abstract: The disclosure describes a process and apparatus for accessing devices on a substrate. The substrate may include only full pin JTAG devices (504), only reduced pin JTAG devices (506), or a mixture of both full pin and reduced pin JTAG devices. The access is accomplished using a single interface (502) between the substrate (408) and a JTAG controller (404). The access interface may be a wired interface or a wireless interface and may be used for JTAG based device testing, debugging, programming, or other type of JTAG based operation.

Abstract: Provided are methods and devices of organizing scan chains in an integrated circuit. One method comprises generating first preference information representing prioritized listing of a plurality of scanning elements for each of a plurality of scan chains based on a first criterion, generating second preference information representing prioritized listing of the plurality of scan chains for each of the plurality of scanning elements based on a second criterion and at a computing device, assigning each of the plurality of the scanning elements to one of the plurality of the scan chains based on the first preference information and the second preference information.

Abstract: A system for re-ordering a scan chain of an electronic circuit design using an electronic design automation (EDA) tool includes a processor and a memory in communication with the processor. The scan chain includes a plurality of scan cells. All connections of the scan chain are disconnected. An output port of a first scan cell is connected to input ports of other scan cells to form a first set of scan cell combinations. A first scan cell combination is selected from the first set of scan cell combinations based on weighted averages of ordering parameters of each of the first set of scan cell combinations. The process is repeated to re-order the scan chain.

Abstract: An integrated circuit carries an intellectual property core. The intellectual property core includes a test access port 39 with test data input leads 15, test data output leads 13, control leads 17 and an external register present, ERP lead 37. A scan register 25 encompasses the intellectual property core and ERP lead 37 carries a signal indicating the presence of the scan register.

Abstract: Test control point insertion and x-bounding for Logic Built-In Self-Test (LBIST) using observation circuitry. In some embodiments, LBIST circuitry may include a plurality of test control circuits coupled to a scan chain of a Circuit Under Test (CUT), and a plurality of observation circuits coupled to the test control circuits, each of the plurality of observation circuits including one or more latch devices configured to drive a respective one of the plurality of test control circuits. In other embodiments, a method of testing an integrated circuit may include issuing an instruction that a plurality of observation circuits and a plurality of input/output (I/O) control circuits within the integrated circuit enter a test mode, and providing, one or more test patterns to a selected one or more of a plurality of scan chains within the integrated circuit and to each of the plurality of observation circuits.

Abstract: Scan architectures are commonly used to test digital circuitry in integrated circuits. The present invention describes a method of adapting conventional scan architectures into a low power scan architecture. The low power scan architecture maintains the test time of conventional scan architectures, while requiring significantly less operational power than conventional scan architectures. The low power scan architecture is advantageous to IC/die manufacturers since it allows a larger number of circuits (such as DSP or CPU core circuits) embedded in an IC/die to be tested in parallel without consuming too much power within the IC/die. Since the low power scan architecture reduces test power consumption, it is possible to simultaneously test more die on a wafer than previously possible using conventional scan architectures. This allows wafer test times to be reduced which reduces the manufacturing cost of each die on the wafer.

Abstract: The present disclosure describes using the JTAG Tap's TMS and/or TCK terminals as general purpose serial Input/Output (I/O) Manchester coded communication terminals. The Tap's TMS and/or TCK terminal can be used as a serial I/O communication channel between; (1) an IC and an external controller, (2) between a first and second IC, or (3) between a first and second core circuit within an IC. The use of the TMS and/or TCK terminal as serial I/O channels, as described, does not effect the standardized operation of the JTAG Tap, since the TMS and/or TCK I/O operations occur while the Tap is placed in a non-active steady state.

Abstract: Testing of die on wafer is achieved by; (1) providing a tester with the capability of externally communicating JTAG test signals using simultaneously bidirectional transceiver circuitry, (2) providing die on wafer with the capability of externally communicating JTAG test signals using simultaneously bidirectional transceiver circuitry, and (3) providing a connectivity mechanism between the bidirectional transceiver circuitry's of the tester and a selected group or all of the die on wafer for communication of the JTAG signals.

Abstract: Topology discovery of a target system having a plurality of components coupled with a scan topology may be performed by driving a low logic value on the data input signal and a data output signal of the scan topology. An input data value and an output data value for each of the plurality of components is sampled and recorded. A low logic value is then scanned through the scan path and recorded at each component. The scan topology may be determined based on the recorded data values and the recorded scan values.

Abstract: An integrated circuit comprises a decoder having a plurality of select signal outputs, a multiplexer having a plurality of select signal inputs subject to a specified select signal constraint, and scan test circuitry. The scan test circuitry comprises at least one scan chain having a plurality of scan cells coupled between respective ones of the select signal outputs of the decoder and respective ones of the select signal inputs of the multiplexer. The scan test circuitry is configured to control at least a given one of the scan cells so as to prevent violation of the select signal constraint in conjunction with scan testing. The multiplexer may be, for example, a one-hot multiplexer for which the select signal constraint indicates that only one of the select signal inputs should receive a logic high select signal at a particular time.

Abstract: A system and method for sharing a communications link between multiple protocols is described. A system includes a communications interface configured to exchange information with other systems using at least one of a plurality of protocols; a protocol select register that stores a value that selects a protocol from among the plurality of protocols to become an active protocol; and a state machine accessible to the communications interface, the state machine used to control the exchange of information through the communications interface according to the active protocol. The active protocol is used by the communications interface to exchange information while the remaining protocols of the plurality of protocols remain inactive. The state machine sequences through a series of states that cause the communications interface to operate according to the active protocol, and that are designated as inert sequences under the remaining protocols.

Abstract: Aspects of the invention relate to ring-oscillator-based test architecture for characterizing interconnects in stacked designs. The disclosed ring-oscillator-based test architecture comprises a plurality of boundary scan cells coupled to a plurality of interconnects. Each of the plurality of boundary scan cells can be configured to operate as, based on control signals, a conventional boundary scan cell or any bit of an asynchronous counter. The control signals are supplied by control circuitry.

Abstract: An integrated circuit can have plural core circuits, each having a test access port that is defined in IEEE standard 1149.1. Access to and control of these ports is though a test linking module. The test access ports on an integrated circuit can be arranged in a hierarchy with one test linking module controlling access to plural secondary test linking modules and test access ports. Each secondary test linking module in turn can also control access to tertiary test linking modules and test access ports. The test linking modules can also be used for emulation.

Abstract: In a first embodiment a Test Access Port (TAP) of IEEE standard 1149.1 is allowed to commandeer control from a Wrapper Serial Port (WSP) of IEEE standard P1500 such that the P1500 architecture, normally controlled by the WSP, is rendered controllable by the TAP. In a second embodiment (1) the TAP and WSP based architectures are merged together such that the sharing of the previously described architectural elements are possible, and (2) the TAP and WSP test interfaces are merged into a single optimized test interface that is operable to perform all operations of each separate test interface. One approach provides for the TAP to maintain access and control of the TAP instruction register, but provides for a selected data register to be accessed and controlled by either the TAP+ATC (Auxiliary Test Control bus) or by the discrete CaptureDR, UpdateDR, TransferDR, ShiftDR, and ClockDR WSP data register control signals.

Abstract: A system for re-ordering a scan chain of an electronic circuit design using an electronic design automation (EDA) tool includes a processor and a memory in communication with the processor. The scan chain includes a plurality of scan cells. All connections of the scan chain are disconnected. An output port of a first scan cell is connected to input ports of other scan cells to form a first set of scan cell combinations. A first scan cell combination is selected from the first set of scan cell combinations based on weighted averages of ordering parameters of each of the first set of scan cell combinations. The process is repeated to re-order the scan chain.

Abstract: Provided are apparatus and methods for testing an integrated circuit. In an exemplary method for testing an integrated circuit, a test controller and a power manager are integrated into a main power domain of the integrated circuit. The test controller can be Joint Test Action Group-compatible. An isolation signal is generated using the power manager. The isolation signal can comprise at least one of a freeze signal configured to isolate an input-output port of the integrated circuit, and a clamp signal configured to isolate a functional module of the integrated circuit. The isolation signal can be stored in a boundary scan register controlled with the test controller. The main power domain is isolated from a power-collapsible domain of the integrated circuit with the isolation signal. Power of the power-collapsible domain is collapsed. When power is collapsed, the power-collapsible domain is tested using the test controller and the power manager.

Abstract: Semiconductor devices configured to test connectivity of micro bumps including one or more micro bumps and a boundary scan test block for testing connectivity of the micro bumps by scanning data input to the micro bumps and outputting the scanned data. The semiconductor device may include a first chip including solder balls and at least one or more switches electrically coupled with the respective solder balls, and a second chip stacked on top of the first chip and electrically coupled with the switches in direct access mode, including micro bumps that input/output signals transmitted from/to the solder balls.

Abstract: Scan distributor, collector, and controller circuitry connect to the functional inputs and outputs of core circuitry on integrated circuits to provide testing through those functional inputs and outputs. Multiplexer and demultiplexer circuits select between the scan circuitry and the functional inputs and outputs. The core circuitry can also be provided with built-in scan distributor, collector, and controller circuitry to avoid having to add it external of the core circuitry. With appropriately placed built-in scan distributor and collector circuits, connecting together the functional inputs and outputs of the core circuitry also connects together the scan distributor and collector circuitry in each core. This can provide a hierarchy of scan circuitry and reduce the need for separate test interconnects and multiplexers.

Abstract: An IC includes an IEEE 1149.1 standard test access port (TAP) interface and an additional Off-Chip TAP interface. The Off-Chip TAP interface connects to the TAP of another IC. The Off Chip TAP interface can be selected by a TAP Linking Module on the IC.

Abstract: IEEE 1149.1 Test Access Ports (TAPs) may be utilized at both IC and intellectual property core design levels. TAPs serve as serial communication ports for accessing a variety of embedded circuitry within ICs and cores including; IEEE 1149.1 boundary scan circuitry, built in test circuitry, internal scan circuitry, IEEE 1149.4 mixed signal test circuitry, IEEE P5001 in-circuit emulation circuitry, and IEEE P1532 in-system programming circuitry. Selectable access to TAPs within ICs is desirable since in many instances being able to access only the desired TAP(s) leads to improvements in the way testing, emulation, and programming may be performed within an IC. A TAP linking module is described that allows TAPs embedded within an IC to be selectively accessed using 1149.1 instruction scan operations.

Abstract: Techniques and mechanisms are provided for an improved built in self-test (BIST) mechanism for 3D assembly defect detection. According to an embodiment of the present disclosure, the described mechanisms and techniques can function to detect defects in interconnects which vertically connect different layers of a 3D device, as well as to detect defects on a 2D layer of a 3D integrated circuit. Additionally, according to an embodiment of the present disclosure, techniques and mechanisms are provided for determining not only the presence of a defect in a given set of interfaces of an integrated circuit, but the particular interface at which a defect may exist.

Abstract: An integrated circuit comprises scan test circuitry and additional circuitry subject to testing utilizing the scan test circuitry. The scan test circuitry comprises a scan chain having a plurality of scan cells. The integrated circuit further comprises a clock distribution network configured to provide clock signals to respective portions of the integrated circuit. The clock distribution network comprises at least one clock module comprising one or more clock dividers and associated clock divider logic, and the scan test circuitry is configured to permit testing of at least a portion of the clock divider logic. A given scan chain of the scan test circuitry may comprise first and second scan cells, with the first scan cell having a scan output coupled to a scan input of the second scan cell, and the second scan cell having a data input driven by an output of the clock divider logic.

Abstract: In an embodiment, a scannable storage element includes an input circuit for providing a first signal at first node based on a data input and a scan input, where the scan input is of pull-up logic in functional mode. The input circuit includes a first pull-up path comprising a switch receiving data input and a switch receiving scan enable input, and second pull-up path comprising a switch receiving scan input, first pull-down path comprising a switch receiving the scan enable input and a switch receiving the scan input, and second pull-down path comprising a switch receiving the data input. The storage element includes a shifting circuit configured to provide a second signal in response to the first signal at second node, and a scan output buffer coupled to the second node and configured to provide a scan output at a scan output terminal in response to the second signal.

Abstract: An apparatus is provided that comprises a test circuit; a first receiver unit arranged to receive test commands and to provide the test commands to the test circuit; a power supply unit arranged to supply power to the test circuit and to the first receiver unit; a second receiver unit arranged to receive power commands. The second receiver is arranged to control the operation of the power supply unit in response to the power commands received by the second receiver unit.

Abstract: An integrated circuit comprises scan test circuitry and additional circuitry subject to testing utilizing the scan test circuitry. The scan test circuitry comprises at least one scan chain having a plurality of scan cells. The scan test circuitry further comprises control circuitry configured to control selective application of at least a particular one of a plurality of reset signals to reset inputs of at least a subset of the scan cells of the scan chain. For example, the control circuitry may comprise a first reset multiplexer configured to select between a first functional mode reset signal and a first scan mode reset signal for application to reset inputs of respective scan cells of the scan chain, and an additional multiplexer configured to select between an additional functional mode reset signal and an additional scan mode reset signal for application to reset inputs of respective internal flip-flops of the additional circuitry.

Abstract: The apparatus and methods allow random hardware failure emulation of an integrated circuit (IC) by emulation of potential defects to enable behavior evaluation of the rest of the design in such situation. This emulation can non-intrusively address multiple points of failure. The emulation is performed in a pseudo-functional mode in order to evaluate the IC behavior in its standard functional mode. The system allows creation of a failure, and tracking both the detection of this failure and the required time for this detection. The system further allows generation of a failure in different points of the IC, on a single or multipoint failure approaches. Failure detection and correction mechanisms for a product life cycle are therefore provided. In an embodiment the system checks the conformity of the safety function of an IC, and makes sure the safety control logic behaves as expected in case of data corruption in any register.

Abstract: A test architecture for 3D ICs is provided in which Through-Silicon-Vias and die logic can be tested pre-bonding dies in the stack for the 3D ICs. Post-bond scan test architecture is reconfigured to be accessed during pre-bond testing through using stratigically placed MUXs and TSVs. By connecting post-bond architecture including scan flops and boundary registers to gated scan flops used in TSV testing, an internal chain of scan flops such as typically used in post-bond testing can be selectively connected to gated scan flops connected to one end of each TSV for pre-bond testing of the internal logic through the TSVs.

Abstract: A method of and an arrangement for determining electric connections at a printed circuit board between boundary-scan compliant circuit terminals of one or more boundary-scan compliant devices. An electronic processing unit retrieves properties of the or each boundary-scan compliant device and a list comprising boundary-scan cells operable as a driver and/or sensor. Based on this list, a boundary-scan cell connected to a circuit terminal is operated as a driver, and at least one other boundary-scan cell connected to another circuit terminal is operated as a sensor. Data from the boundary-scan register, comprising the driver and sensor data, is stored in a storage device. The steps of operating boundary-scan cells as driver and sensor are repeated for a plurality of cells. The data stored are analyzed for determining electric connections. A result of the analysis is presented.

Abstract: A method for performing scan based tests is presented. The method comprises routing scan data serially from a plurality of I/O ports to a plurality of partitions of an integrated circuit using a first clock signal operating at a first frequency, wherein each partition comprises a plurality of internal scan chains. The method also comprises deserializing the scan data to feed internal scan chains. Further, the method comprises generating a plurality of second clock signals operating at a second frequency using the first clock signal, wherein each partition receives a respective one of the plurality of second clock signals and wherein the plurality of second clock signals are staggered wherein each pulses at a different time. Finally, the method comprises shifting in the scan data into the internal scan chains at the rate of the second frequency.

Abstract: A scan flip flop includes a partial multiplexer coupled to a master latch. The partial multiplexer is configured to receive a scan enable (SCAN) where the partial multiplexer includes an OR gate coupled to a tri-stated AND gate. A tri-state inverter is coupled to an output of the master latch and a slave latch is configured to receive an output of the tri-state inverter. A delay element is coupled to the slave latch, where the delay element is configured to delay a first output of the slave latch in response to the scan enable to generate a dedicated scan output.

Abstract: Scan architectures are commonly used to test digital circuitry in integrated circuits. The present invention describes a method of adapting conventional scan architectures into a low power scan architecture. The low power scan architecture maintains the test time of conventional scan architectures, while requiring significantly less operational power than conventional scan architectures. The low power scan architecture is advantageous to IC/die manufacturers since it allows a larger number of circuits (such as DSP or CPU core circuits) embedded in an IC/die to be tested in parallel without consuming too much power within the IC/die. Since the low power scan architecture reduces test power consumption, it is possible to simultaneously test more die on a wafer than previously possible using conventional scan architectures. This allows wafer test times to be reduced which reduces the manufacturing cost of each die on the wafer.