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 scan flip-flop circuit includes a selection circuit including first and second input terminals coupled to first and second I/O nodes, a flip-flop circuit coupled to the selection circuit, a first driver coupled between the flip-flop circuit and the first I/O node, and a second driver coupled between the flip-flop circuit and the second I/O node. The selection circuit and drivers receive a scan direction signal. In response to a first logic level of the scan direction signal, the selection circuit responds to a first signal received at the first input terminal, and the second driver outputs a second signal responsive to a flip-flop circuit output signal. In response to a second logic level of the scan direction signal, the selection circuit responds to a third signal received at the second input terminal, and the first driver outputs a fourth signal responsive to the flip-flop circuit output signal.

A dummy dual in-line memory module (DIMM) testing system based on boundary scan interconnect and a method thereof. A dummy dual in-line memory module functioning normally is used as a test fixture, a dummy dual in-line memory module under test is served as an unit under test (UUT), and the test fixture and the unit under test are inserted into a test device to electrically connect to each other, so that the test access port (TAP) device can perform boundary scan to control the test fixture to test the unit under test through signal pins, and check a test result based on a data signal collected from at least one boundary scan register. Therefore, the effect of improving testing convenience of the dummy DIMM can be achieved.

A detection system for a SlimSAS slot and a method thereof are disclosed. In the detection system, a detecting device generates and transmits a detection signal to a TAP controller; the TAP controller converts the received detection signal into a detection signal in JTAG format, and transmits the detection signal in JTAG format to a CPLD chip and a controllable power module chip of a detection card and/or a boundary scan chip of a circuit board; a detection can be performed on the SMBus pins, the differential signal receiving pins, the differential signal transmitting pins, the clock pins, the sideband pins and the ground pins of the SlimSAS connection interface through the boundary scan chip, the HCSL to LVDS module chip, the IIC chip and the CPLD chip. Therefore, the technical effect of improving slot stability and detection coverage of a SlimSAS slot detection can be achieved.

A pin conduction detection system for connector slot of circuit board, and a method thereof are disclosed. A connector slot detection circuit board is plugged on a connector slot of a to-be-detected circuit board, and the connector slot detection circuit boards including different types of connector slots are concatenated with each other. A TAP controller can set a JTAG chip of the connector slot detection circuit board to be in a boundary scan mode, and the JTAG chip can read at least one detection signal corresponding to at least one detection pin of the connector slot connector via one of a ADC, a microprocessor, and a switch, so that the TAP controller can perform an conduction detection on the pin of the connector slot corresponding to the detection signal. As a result, test efficiency and coverage rate of testing the connector slot of the circuit board can be improved.

A pin connection testing system for connector, and a method thereof are disclosed. In the pin connection testing system, a JTAG instruction is used to control a PLD, to drive the demultiplexer to transmit each to-be-tested signal, which is from the connector, to a first line or a second line; and, when the to-be-tested signal is transmitted to the first line, the to-be-tested signal is converted from analog to digital and encoded, and then transmitted to I/O pins of the PLD for reading; and, when the JTAG command is transmitted to the second line, the PLD reads the statuses of the I/O pins electrically connected to the second line; and then the PLD generates a test result according to the to-be-tested signals and the read I/O pins. Therefore, the technical effect of improving convenience in testing the connection status of the connector can be achieved.

A system for using different scan chains to test differential circuit and a method thereof are disclosed. In the system, two scan chains are set up for two electronic components on a target circuit board, and test data for the two scan chains are sequentially pushed to the two scan chains respectively according to a data flow direction between the two scan chains, and after the electronic components output result data, a test result can be determined according to the test data for the two scan chains and the result data. This testing manner can be performed on all electronic components, so as to achieve the technical effect of stably performing differential signal test on all electronic components of the target circuit board.

A method for testing inter-layer connections is presented. The method entails: providing a test semiconductor device, wherein the test semiconductor device comprises a two-port resistance network; measuring base input resistances on at least one of the first and the second ports of the test semiconductor device for different numbers of resistance links in a defect-free circumstance; obtaining a correspondence relationship between the number of resistance links and the base input resistances; measuring actual input resistances on at least one of the first and the second ports of the test semiconductor device; and determining a position of the resistance link corresponding to the actual input resistances based on the correspondence relationship, wherein the position of the resistance link determines the location of a defect. This method can promptly locate a defect in inter-layer components and can reduce test time and simplify test procedures.

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 reconfigurable scan network in a circuit is configured such that a first scan path is used if a programmable component has no stuck-at fault and a second scan path is used if the programmable component has a stuck-at fault. A test pattern having a length equal to a length of the second path is shifted into the reconfigurable scan network, and a part or a whole of the test pattern is then shifted out from the reconfigurable scan network. The part or the whole of the test pattern being shifted out is analyzed to determine whether the programmable component has the stuck-at fault.