A circuit includes a test data input (TDI) pin receiving a test data input signal, a test data out (TDO) pin outputting a test data output signal, and debugging test access port (TAP) having a test data input coupled to the TDI pin and a bypass register having an input coupled to the test data input of the debugging TAP. A multiplexer has inputs coupled to the TDI pin and the debugging TAP. A testing TAP has a test data input coupled to the output of the multiplexer, and a data register having an input coupled to the test data input of the testing TAP. The multiplexer switches so the test data input signal is selectively coupled to the input of the data register of the testing TAP so the output of the debugging TAP is selectively coupled to the input of the data register of the testing TAP.

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.

Various aspects of the disclosed technology relate to using capture-per-cycle test points to reduce test application time. A scan-based testing system includes a plurality of regular scan chains and one or more capture-per-cycle scan chains on which scan cells capture and compact test responses at predetermined observation points per shift clock cycle.

An implementation of a system disclosed herein includes a decompressor logic with the capability to vary a level of decompression of a scanning input signal based on value of compression program bits and a compressor logic to generate a scanning output signal, the compressor logic including a plurality of XOR logics, wherein the output of the plurality of XOR logics is selected based on the compression program bits.

In a compression scan, the number of test steps is reduced without reducing a defection efficiency. A semiconductor apparatus includes one or more scan chains each including one or more MMSFFs being serially connected and combinational circuits and can switch between a scan shift operation and a capture operation. The MMSFF includes an MUX that selects one of an external input test signal which is externally input and a shift test signal which is input via the MMSFF in a preceding stage in the same scan chain, and an FF that outputs one of the external input test signal and the shift test signal which has been selected by the MUX.

A circuit is for coupling test access port (TAP) signals to a Joint Test Action Group (JTAG) interface in an integrated circuit package. An nTRST pin receives a test reset signal, a TMS pin receives a test mode select signal, a testing test access port (TAP) has a test reset signal input and a test mode select signal input, and a debugging test access port (TAP) has a test reset signal input coupled to the nTRST pin and a test mode select signal input coupled to the TMS pin. An inverter has an input coupled to the nTRST pin and an output coupled to the test reset signal input of the testing TAP, and an AND gate has a first input coupled to the output of the inverter, a second input coupled to the TMS pin, and an output coupled to the test mode select input of the testing TAP.

A method of testing an IC chip having a plurality of programmable blocks and at least one memory. The method includes configuring a first programmable block of the plurality of programmable blocks with scan test logic for carrying out a scan test on other ones of the plurality of programmable blocks. The method further includes generating scan patterns and expected results for the scan test outside the IC chip. The generated scan patterns and expected results are loaded into the memory. The scan patterns from the memory are injected into the other programmable blocks. An output response of the other programmable blocks to the scan patterns is obtained. The output response is compared with the expected results by the scan test logic within the first programmable block. A scan test result based on the comparison between the output response and the expected results is provided.

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).

A distributed test circuit includes partitions arranged in series to form a scan path, each partition including a scan multiplexer, a test data register, and a segment insertion bit component. The scan multiplexer of each partition provides inputs to the corresponding test data register of the each partition. Broadcast control logic generates a select signal to the scan multiplexer of each partition to place the test circuit in a broadcast mode when the select signal is asserted, and to switch the test circuit to a daisy mode when select signal is de-asserted. The segment insertion bit is operable to include or bypass each partition from the scan path.

Embodiments include systems and methods for in-system, scan-based device testing using novel narrow-parallel (NarPar) implementations. Embodiments include a virtual automated test environment (VATE) system that can be disposed within the operating environment of an integrated circuit for which scan-based testing is desired (e.g., a chip under test, or CuT). For example, the VATE system is coupled with a service processor and with the CuT via a novel NarPar interface. A sequence controller can drive a narrow set of parallel scan pins on the CuT via the NarPar interface of the VATE system in accordance with an adapted test sequence having bit vector stimulants and expected responses. Responses of the CuT to the bit vector stimulants can be read out and compared to the expected results for scan-based testing of the chip.