A first clock signal and second clock signal are generated by first and second clock circuits, respectively. A multiplexer selects between the first clock signal and second clock signal to produce a scan clock signal. A non-scan flip flop clocks a data input through to a data output in response to the second clock signal. A scan chain includes a scan flip flop configured to capture the data output from the non-scan flip flop in response to the scan clock signal. The logic state of the captured data in the scan flip flop of the scan chain is indicative of whether the second clock circuit has a stuck-at fault condition (for example, with respect to any one or more included buffer circuits).

A method of debugging a printed circuit board with at least one boundary-scan compliant device is presented. The method uses an electronic processing unit and includes the steps of: retrieving boundary-scan properties of the at least one boundary-scan compliant device, the properties including a listing of boundary-scan compliant circuit terminals of the at least one boundary-scan compliant device; retrieving connectivity properties; selecting and displaying a circuit graph of at least a part of the devices mounted on the printed circuit board, the circuit graph including at least one of the devices mounted on the printed circuit board and a least one further device from the devices which has a circuit terminal interconnected to a circuit terminal of the device for visualizing at least the device, the further device and interconnects between the circuit terminals of the devices.

A method for repairing a processor. The processor comprises a plurality of processing units and an exchange comprising a plurality of exchange paths for transmitting data between the processing units. Each processing unit is connected to output data to a respective exchange path. An exchange path functional test of at least a portion of the exchange paths is carried out. Based on the exchange path functional test, it is identified that one or more of the exchange paths is defective, and the processing units connected to the one or more defective exchange paths is identified. The identified processing units are switched out of functional operation of the processor and switching in at least one repair processing unit connected to a non-defective exchange path for functional operation of the processor.

One aspect provides an FPGA chip mounted on a printed circuit board (PCB). The FPGA chip can include a joint test action group (JTAG) interface comprising a number of input/output pins and an enablement pin, and a control logic block coupled to the enablement pin of the JTAG interface. The control logic block can receive a control signal from an off-chip control unit and control a logical value of the enablement pin based on the received control signal, thereby facilitating the off-chip control unit to lock or unlock the JTAG interface. The FPGA chip can further include a detection logic block to detect an unauthorized access to the FPGA chip. An input to the detection logic is coupled to the enablement pin, and a conductive trace coupling the input of the detection logic block and the enablement pin is situated on an inner layer of the PCB.

A multi-die chip module (MCM) comprises a first die containing a first test controller and a second die containing a second test controller coupled to the first die via an interconnect. The first test controller is configured to place the first die in either a shift mode or a capture mode. The second controller is configured to place the second die in either the shift mode or the capture mode. After a scan shift operation, scan cells are initialized to predetermined values. During the capture operation one die remains in the shift mode and the other die enters the capture mode so that as test bits are shifted into registers associated with output pads on the die in the shift mode, the other die is in the capture mode and captures signals on input pads associated with that die, enabling scan based at-speed testing of the interconnect.

Various aspects of the disclose techniques relate to techniques of testing interconnects in stacked designs. A single-pulse signal, generated by a first circuit state element on a first die, is applied to a first end of an interconnect and captured at a second end of the interconnect using a clock port of a second circuit state element on a second die. A faulty interconnect may cause the single-pulse signal too distorted to reach the threshold voltage of the second circuit element.

Aspects include techniques for implementing a clock path technique for using on-chip circuitry to generate a correct encode pattern to test the on-chip circuitry for encoding and correction of a chip. A computer-implemented method may include initializing a scan of the chip including data and a set of check bits protecting the data; applying a global control bit to a latch on the chip; and applying an additional clock to the latch so the check bits are updated using the on-chip circuitry.

An integrated circuit includes a ring oscillator circuit and a plurality of logic paths. Each logic path comprises a path input connection, a path output connection and an input multiplexer, which has an output connection that is connected to the path input connection of the logic path. Each logic path, beginning with a first logic path, is assigned a respective subsequent logic path by virtue of the path output connection of the logic path being connected to a data input connection of the input multiplexer of the subsequent logic path. A last logic path of the logic paths is assigned the first logic path as subsequent logic path. For each logic path, the multiplexer is configured such that, when a control signal that indicates a test mode is fed thereto, it connects the data input connection of the input multiplexer to the path input connection of the logic path.

A test coverage rate improvement system for pins of tested circuit board and a method thereof are disclosed. In the system, partial pins of a circuit board connector in a tested circuit board are not electrically connected to the boundary scan chip, test pins of the test pin board are pressed with the partial pins by a fixture of a boundary scan interconnect testing workstation to electrically connect the test pins to the partial pins. A test access port controller receives a detection signal for detecting the partial pins, which are not electrically connected to the boundary scan chip, of the circuit board connector through the test pin board from the test adapter card, and determines whether conduction is formed based on the detection signal, thereby achieving the technical effect of improving a test coverage rate for the pins of the tested circuit board.

A Switching Mode Interposer (SMI) arrangement for boundary-scan testing of a Multi-Chip Module having a System-On-Chip, a Microprocessor Control Unit, and multiple chiplets-based devices including central processing units, graphical processing units, and/or memory devices disposed on a two-tiered interposer-substrate system. The SMI includes (a) a twin Test Access Port connected to a JTAG controller and configured to transmit test data in one direction (TAP-X) and an opposite direction (TAP-Y) along an Inter-Integrated Circuit (I2C) bus connected with the SOC, the MCU and the multiple devices, the test data being formatted according to IEEE 1149.1 or IEEE 1149.7 standard; and (b) a Mux/DeMux switch connected to the twin TAP and the I2C bus and responsive to the SOC or the MCU for selective switching of the test data along either the TAP-X or TAP-Y direction to a predetermined port associated with one of the multiple devices.