Abstract: An integrated circuit 2 is provided with a serial scan chain. Disposed between at least some serial scan cells 32, 34 forming a serial scan chain there is provided a partial scan cells 36. These partial scan cells are arranged such that during a scan mode in which serial data is being shifted into and out of the serial scan cells, a fixed value is captured and stored into the partial scan cell 36. This avoids the presence of unknown data values within the signal paths between the functional logic 38, 40 which is to be tested.

Abstract: The disclosure describes a novel method and apparatus for providing a shadow access port within a device. The shadow access port is accessed to perform operations in the device by reusing the TDI, TMS, TCK and TDO signals that are used to operate a test access port within the device. The presence and operation of the shadow access port is transparent to the presence and operation of the test access port. According to the disclosure, the shadow access port operates on the falling edge of the TCK signal while the test access port conventionally operates on the rising edge of the TCK signal.

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 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: 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: An integrated circuit (IC) structure can include a first die and a second die. The second die can include a first base unit and a second base unit. Each of the first base unit and the second base unit is self-contained and no signals pass between the first base unit and the second base unit within the second die. The IC structure can include an interposer. The interposer includes a first plurality of inter-die wires coupling the first die to the first base unit, a second plurality of inter-die wires coupling the first die to the second base unit, and a third plurality of inter-die wires coupling the first base unit to the second base unit.

Abstract: Circuits and a method for testing an integrated circuit (IC) are disclosed. A disclosed circuit block includes a selector circuit that is coupled to receive an enable signal and two clock signals. One of the two clock signals is selected as an output of the selector circuit based on the enable signal received. A storage element is coupled to receive the enable signal and the output of the selector circuit as a clock input signal. A logic gate is coupled to receive the output of the storage element and the enable signal. Another selector circuit is coupled to receive an output from the logic gate and the enable signal. The selector circuit selects either the output from the logic gate or the enable signal as a scan enable signal for a scan chain on the IC.

Abstract: Scan flip-flop and associated method are provided. The scan flip-flop includes a data input terminal, a scan input terminal, a flip-flop circuit, a first transistor and a plurality of second transistors. A gate of the first transistor is coupled to the scan input terminal, gates of the second transistors are commonly coupled to an enabling signal, drains and sources of the first transistor and the second transistors are serially coupled to the flip-flop circuit, so as to increase a delay between the scan input terminal and the flip-flop circuit.

Abstract: A scan chain includes a plurality of scan chain blocks coupled together in series and reference circuitry inserted before one of the plurality of scan chain blocks. The reference circuitry, in a scan mode of operation, receives a scan input signal. In a test data capture mode of operation, the reference circuitry receives a known test signal value, and, in a scan out mode of operation, outputs the known test signal value to the one scan chain block of the plurality of scan chain blocks.

Abstract: The invention relates to an electronic circuit (10) having one or more latch scan chains (12), the electronic circuit (10) comprising (i) a built-in test structure (14); (ii) generation means (16) for simultaneously generating scan-in data for each of said scan chains (12); (iii) interception means (18) for simultaneously intercepting test lines (20) of said scan chains (12), said test lines (20) comprising scan-in lines (22) and/or control lines (24). Said interception means (18) are responsive to said generation means (16) in order to simultaneously feed the generated scan-in data into each of said scan chains (12) for initializing the electronic circuit (10). The invention further relates to a method for initializing an electronic circuit (10), as well as a data processing system (210) for initializing an electronic circuit (10).

Abstract: The disclosure describes a novel method and apparatus for improving the operation of a TAP architecture in a device through the use of Command signal inputs to the TAP architecture. In response to a Command signal input, the TAP architecture can perform streamlined and uninterrupted Update, Capture and Shift operation cycles to a target circuit in the device or streamlined and uninterrupted capture and shift operation cycles to a target circuit in the device. The Command signals can be input to the TAP architecture via the devices dedicated TMS or TDI inputs or via a separate CMD input to the device.

Abstract: A semiconductor device, a test structure of the semiconductor device, and a method of testing the semiconductor device are provided. The test structure including a first pad and a second pad being separated from each other, and a first test element and a second test element connected between the first pad and the second pad, a first value of a characteristic parameter of the first test element being different from a second value of the characteristic parameter of the second test element, may be provided.

Abstract: Aspects of the invention relate to techniques for determining scan chains that could be diagnosed with high resolution. A circuit design and the information of scan cells for the circuit design are analyzed to determine information of potential logic relationship between the scan cells. The information of potential logic relationship between the scan cells may comprise information of fan-in cones for the scan cells. Based at least in part on the information of potential logic relationship between the scan cells, scan chains may be formed. The formation of scan chains may be further based on layout information of the circuit design. The formation of scan chains may be further based on compactor information of the circuit design.

Abstract: Scan testing of plural target electrical circuits, such as circuits 1 through N, becomes accelerated by using the scan test response data output from one circuit, such as circuit 1, as the scan test stimulus data for another circuit, such as circuit 2. After reset, a scan path captures the output response data from the reset stimulus from all circuits. A tester then shifts the captured data only the length of the first circuit's scan path while loading the first circuit's scan path with new test stimulus data. The new response data from all the circuits then is captured in the scan path. This shift and capture cycle is repeated until the first circuit is tested. The first circuit is then disabled and any remaining stimulus data is applied to the second circuit. This process is repeated until all the circuits are tested. A data retaining boundary scan cell used in the scan testing connects the output of an additional multiplexer as the input to a boundary cell.

Abstract: An integrated circuit is configured to receive a test clock input and includes circuitry configured to generate test clocks from the test clock input, and test circuitry configured to use the test clocks in a test mode.

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: Scan-based reset utilizes already existing design-for-test scan chains to reset control and logic circuitry upon reset conditions, such as power-up reset. Such utilization eliminates the need for expensive, high fan-out reset trees and per scan cell reset control logic, thus reducing chip area and power consumption. Additional power savings is achieved by controlling clock frequency during reset conditions. Limiting scan cell chain length and providing multiple chains reduces reset latency.

Abstract: Methods and apparatuses for generating compressed test data for use by a tester, decompressing the test data during test, and routing the decompressed test data into a set of scan chains within a circuit under test are described.

Abstract: The disclosure describes a novel method and apparatus for providing expected data, mask data, and control signals to scan test architectures within a device using the falling edge of a test/scan clock. The signals are provided on device leads that are also used to provide signals to scan test architectures using the rising edge of the test/scan clock. According to the disclosure, device test leads serve to input different test signals on the rising and falling edge of the test/scan clock which reduces the number of interconnects between a tester and the device under test.

Abstract: A test controller applies test stimulus signals to the input pads of plural die on a wafer in parallel. The test controller also applies encoded test response signals to the output pads of the plural die in parallel. The encoded test response signals are decoded on the die and compared to core test response signals produced from applying the test stimulus signals to core circuits on the die. The comparison produces pass/fail signals that are loaded in to scan cells of an IEEE 1149.1 scan path. The pass/fail signals then may be scanned out of the die to determine the results of the test.

Abstract: A system comprises a plurality of components, scan chain selection logic coupled to the components, and override selection logic coupled to the scan chain selection logic. The scan chain selection logic selects various of the components to be members of a scan chain under the direction of a host computer. The override selection logic detects a change in the scan chain and, as a result, blocks the entire scan chain from progressing.

Abstract: This disclosure describes a reduced pin bus that can be used on integrated circuits or embedded cores within integrated circuits. The bus may be used for serial access to circuits where the availability of pins on ICs or terminals on cores is limited. The bus may be used for a variety of serial communication operations such as, but not limited to, serial communication related test, emulation, debug, and/or trace operations of an IC or core design. Other aspects of the disclosure include the use of reduced pin buses for emulation, debug, and trace operations and for functional operations. In a fifth aspect of the present disclosure, an interface select circuit, FIGS. 41-49, provides for selectively using either the 5 signal interface of FIG. 41 or the 3 signal interface of FIG. 8.

Abstract: An integrated circuit is described that includes a stored program processor for test and debug of user-definable logic plus external interface between the test/debug circuits and the component pins. The external interface may be via an existing test interface or a separate serial or parallel port. Test and debug circuits may contain scan strings that may be used to observe states in user-definable logic or be used to provide pseudo-random bit sequences to user-definable logic. Test and debug circuits may also contain an on-chip logic analyzer for capturing sequences of logic states in user-definable circuits. Test and debug circuits may be designed to observe states in user-definable circuits during the normal system operation of said user-definable circuits.

Abstract: A semiconductor integrated circuit has: N input terminals; N output terminals; a plurality of flip-flops including N flip-flops and R redundant flip-flops; a selector section configured to select N selected flip-flops from the plurality of flip-flops depending on reconfiguration information and to switch data flow such that data input to the N input terminals are respectively output to the N output terminals by the N selected flip-flops; and an error detection section. At a test mode, the N flip-flops form a scan chain and a scan data is input to the scan chain. The error detection section detects an error flip-flop included in the N flip-flops based on scan input/output data respectively input/output to/from the N flip-flops at the test mode and further generates the reconfiguration information such that the detected error flip-flop is excluded from the N selected flip-flops.

Abstract: Background scan cells are selected from scan cells in a circuit based on specified bit distribution information for a plurality of test cubes generated for testing the circuit. A main portion and a background portion are then determined for each test cube in the plurality of test cubes. The background portion corresponds to the background scan cells. Test cubes in the plurality of test cubes that have compatible main portions are merged into test cube groups. Each test cube group in the test cube groups comprises a main test cube and background test cubes. A main test cube, supplied by a tester or a decompressor, may be shifted into the scan chains. A background test cube may be shifted into background chains and be inserted into the main test cube in the scan chains based on control signals.

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: 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: The disclosure describes a novel method and apparatuses for allowing a controller to select and access different types of access ports in a device. The selecting and accessing of the access ports is achieved using only the dedicated TDI, TMS, TCK, and TDO signal terminals of the device. The selecting and accessing of device access ports can be achieved when a single device is connected to the controller, when multiple devices are placed in a daisy-chain arrangement and connected to the controller, or when multiple devices are placed in a addressable parallel arrangement and connected to the controller. Additional embodiments are also provided and described in the disclosure.

Abstract: Methods, systems, and apparatuses are presented that remove BIST intrusion logic from critical timing paths of a microcircuit design without significant impact on testing. In one embodiment, BIST data is multiplexed with scan test data and serially clocked in through scan test cells for BIST testing. In another embodiment, BIST data is injected into the feedback path of one or more data latches. In a third embodiment, BIST data is injected into the result data path of a multi-cycle ALU within an execution unit. In each embodiment, BIST circuitry is eliminated from critical timing paths.

Abstract: According to at least one exemplary embodiment, a synchronous active high reset scan flip flop is provided. The synchronous active high reset scan flip flop may include a data input, a serial input, a test enable input, a reset input, a clock input, a device output. It may also include an AND gate configured to receive the serial input and the test enable input and a multiplexer configured to receive the data input and a first output signal received from the AND gate. The multiplexer is operable in response to the reset input which is used to reset the flip flop in function mode, and permit scan test in test mode. The synchronous active high reset scan flip flop may also include a storage element configured to receive a second output signal received from the multiplexer and operable in response to a clock signal received from the clock input.

Abstract: The disclosure describes novel methods and apparatuses for accessing test compression architectures (TCA) in a device using either a parallel or serial access technique. The serial access technique may be controlled by a device tester or by a JTAG controller. Further the disclosure provides an approach to access the TCA of a device when the device exists in a daisy-chain arrangement with other devices, such as in a customer's system. Additional embodiments are also provided and described in the disclosure.

Abstract: A socket can include a plurality of pins. The socket may be tested to determine if there are any faults or defects. For example, it can be determined whether any of the plurality of pins is bent or missing.

Abstract: This disclosure describes a test architecture that supports a common approach to testing individual die and dies in a 3D stack arrangement. The test architecture uses an improved TAP design to facilitate the testing of parallel test circuits within the die.

Abstract: A method comprises a system comprising a host device coupled to a first remote device actively operating according to a state diagram that the host device and all remote devices follow during operation of the system. The method further comprises powering up a second remote device while the host device and first remote device are actively operating according to the state diagram. The second remote device determines whether to initialize to a standard protocol or to an advanced protocol. Upon determining to initialize to the advanced protocol, the second remote device then waits for a synchronization point sequence.

Abstract: A device test architecture and interface is provided to enable efficient testing embedded cores within devices. The test architecture interfaces to standard IEEE 1500 core test wrappers and provides high test data bandwidth to the wrappers from an external tester. The test architecture includes compare circuits that allow for comparison of test response data to be performed within the device. The test architecture further includes a memory for storing the results of the test response comparisons. The test architecture includes a programmable test controller to allow for various test control operations by simply inputting an instruction to the programmable test controller from the external tester. The test architecture includes a selector circuit for selecting a core for testing. Additional features and embodiments of the device test architectures are also disclosed.

Abstract: The disclosure describes a novel method and apparatus for improving interposers that connected stacked die assemblies to system substrates. The improvement includes the addition of IEEE 1149.1 circuitry within interposers to allow simplifying interconnect testing of digital and analog signal connections between the interposer and system substrate it is attached too. The improvement also includes the additional 1149.1 controlled circuitry that allows real time monitoring of voltage supply and ground buses in the interposer. The improvement also includes the additional of 1149.1 controlled circuitry that allows real time monitoring of functional digital and analog input and output signals in the interposer. The improvement also provides the ability to selectively serially link the 1149.1 circuitry in the interposer with 1149.1 circuitry in the die of the stack.

Abstract: The disclosure provides a novel method and apparatus for inputting addresses to devices to select the device TAP for access. Further, the disclosure provides a novel method and apparatus for inputting addresses for selecting device TAPs and for inputting commands for commanding circuitry within the device. The inputting of addresses or the inputting of addresses and commands is initiated by a control bit input on TDI that is recognized during the Run Test/Idle, Pause-DR or Pause-IR TAP states.

Abstract: Functional circuits and cores of circuits are tested on integrated circuits using scan paths. Using parallel scan distributor and collector circuits for these scan paths improves test access of circuits and cores embedded within ICs and reduces the IC's power consumption during scan testing. A controller for the distributor and collector circuits includes a test control register, a test control state machine and a multiplexer. These test circuits can be connected in a hierarchy or in parallel. A conventional test access port or TAP can be modified to work with the disclosed test circuits.

Abstract: A method for scan testing a three-dimensional chip, comprising: establishing a scan forest structure for the three-dimensional chip; generating a first test set and a plurality of test periods, and dividing the first test set into a plurality of test subsets; distributing test vectors in the plurality of test subsets into the plurality of test periods; obtaining a current hotspot of the three-dimensional chip; ranking the plurality of test subsets in accordance with an order of temperature rising values from small to large to obtain a test vector strategy; selecting the test subsets corresponding to the temperature rising values less than a temperature threshold from the plurality of test subsets according to the test vector strategy, so as to generate a second test set; and applying the second test set to the scan forest structure, and updating the current hotspot of the three-dimensional chip.

Abstract: A scan chain of an integrated circuit is disclosed, including a plurality of scannable storage elements and a control test point having a scan latch and an integrated clock gate (ICG) with clock, functional enable (FE) and scan enable (SE) inputs, and a gated clock output. The ICG may respond to an SE input active state, in a serial scan mode allowing the gated clock output to change. The ICG may also be operated in a scan capture mode, responding to an SE input inactive state, in which the gated clock output is inhibited from changing in response to a low FE input level. The ICG's gated clock output may be coupled to the scan latch clock input, which may hold its data output at a fixed level in response to ICG's gated clock output being inhibited from changing during the scan capture operation.

Abstract: In one embodiment, an integrated circuit chip has an input/output (I/O) interface and programmable fabric. The I/O interface restricts access to scan testing of the chip by requiring (1) a specific scan-testing instruction, (2) a specific manufacturing key, and (3) a specific fabric pattern value from a specific set of registers in the programmed fabric. In addition or alternatively, the I/O interface has circuitry that enables scan testing of most of the logic of the I/O interface itself, including the logic being driven by the JTAG TAP state register.

Abstract: A device test architecture and a reduced device test interface are provided to enable efficient testing of embedded cores and other circuits within devices. The reduced device test interface is achieved using a double data rate (DDR) signaling technique between the tester and the device. The DDR test interface allows the tester to interface to test circuits within the device, such as IEEE 1500 and/or IEEE 1149.1 test circuits, to provide high test data bandwidth to the test circuits using a minimum of test interface signals. The test architecture includes compare circuits that allow for comparison of test response data to be performed within the device. The test architecture further includes a memory for storing the results of the test response comparisons. The test architecture includes a programmable test controller to allow for various test control operations by simply inputting an instruction to the programmable test controller from the external tester.

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: A method of detecting uninitialized memory reads is shown where either all or a subset of a random access memory system is initialized to a know value. One or more watch points are implemented where after a memory read is detected the value read is compared to the value written during initialization. If the values match debug information is captured and appropriate corrective action is taken.

Abstract: Apparatus and method for testing an integrated circuit. An integrated circuit includes circuitry to be tested, scan chain logic, and a test adapter. The scan chain logic is configured to transfer test data to and test results from the circuitry. The test adapter is configured to extract the test data from a packet received from an automated test control system and to transfer the test data to the scan chain logic. The test adapter is also configured to receive the test results from the scan chain logic, and to packetize the test result for transmission to the automated test control system.

Abstract: An integrated circuit (IC) includes an on-chip logic that includes an input terminal, an output terminal, and a plurality of synchronizing circuits connected in a scan-chain; a test data in (TDI) line; a test data out (TDO) line connected to the output terminal; and a test access port (TAP) controller that transmits, to the input terminal, data output from one of a plurality of data sources, the data sources including the TDI line and the output terminal, in response to one or more selection signals.

Abstract: In a first embodiment a TAP 318 of IEEE standard 1149.1 is allowed to commandeer control from a WSP 202 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.

Abstract: Various embodiments of methods and integrated circuits capable of generating a test mode control signal for a scan test through a scan chain (such as in an integrated circuit) are provided. The integrated circuit includes a test pattern detection block, a counter circuit, and a control circuit. The test pattern detection block is configured to receive a detection pattern and to detect a first pattern corresponding to a shift phase and a second pattern corresponding to a capture phase of a test pattern based on the detection pattern and to generate a trigger signal based upon the detection of the patterns. The control circuit generates and controls the test mode control signal based on the count states. The counter circuit is configured to generate one or more count states corresponding to one of the shift phase, the capture phase and the clock signal based on the detected pattern.

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: A process and apparatus provide a JTAG TAP controller (302) to access a JTAG TAP domain (106) of a device using a reduced pin count, high speed DDR interface (202). The access is accomplished by combining the separate TDI and TMS signals from the TAP controller into a single signal and communicating the TDI and TMS signals of the single signal on the rising and falling edges of the TCK driving the DDR interface. The TAP domain may be coupled to the TAP controller in a point to point fashion or in an addressable bus fashion. The access to the TAP domain may be used for JTAG based device testing, debugging, programming, or other type of JTAG based operation.