Invention achieves reduced amount of terminals to control a test mode, test function and test results of a given standard for at least one wrapped core (40,100) (a core 100 surrounded by a wrapper boundary register (40) as wrapper chain). Test flexibility and speed of testing the core (100) are also improved. Suggested serial test interface comprises a state machine (210) and an instruction register (213) for wrapper-instructions, supplied through a single physical data input terminal (1a). The state machine (210) reads wrapper-instructions held by the instruction register (213) and generates on-chip wrapper control signals (30) of the given standard for the wrapper boundary register (40) of the core (100). At least one wrapper-instruction read from the Instruction Register (213) provides at least one wrapper control signal (30). The single input terminal (1a) also supplies an input test signal SDI for coupling to the wrapper boundary register (40) as on chip logical input test signal WSI. A single output terminal (1b) returns an output test signal SDO from an output WSO of the wrapper boundary register (40). Invention may apply to IEEE 1500 control signals.

Embodiments include a power isolation circuit. The power isolation circuit includes a logic block, a wrapper cell, an isolation cell, a test control unit, and/or a power control unit. The power control unit is coupled to the isolation cell and configured to receive a DFT internal core test mode control signal and a clamp control signal, and control the isolation cell dependent on the DFT internal core test mode control signal and the clamp control signal. Also disclosed is a multi-power domain multi-power isolation system, which includes a first power domain and a second power domain. The first power domain includes a logic block, wrapper cells, isolation cells, and a power control unit. The second power domain includes a logic block, wrapper cells, and level-shifter cells. The power control unit is coupled to the isolation cells. Additional power domains with similar characteristics can be included in the design.

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.

A semiconductor device includes a FIFO, a test data write circuit that sequentially writes a plurality of test data to the FIFO in synchronization with a first clock signal, and a test control circuit that, in parallel with writing of the plurality of test data to the FIFO by the test data write circuit, sequentially reads a plurality of test data stored in the FIFO in synchronization with a second clock signal that is not synchronous with the first clock signal and performs a scan test of a circuit to be tested.

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.

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.

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.

The present disclosure illustrates a testing circuit board with self-detection function and a self-detection method. A test for a to-be-tested circuit board is executed and a self-detection for a testing circuit board is performed by a JTAG chip. After the self-detection is passed, a first JTAG connection interface and a second JTAG connection interface are conducted by a controller, a multiplexer and a switch chip, to connect test circuit boards in series. Therefore, the efficiency of solving self-detection of JTAG chip with series connection conveniently and quickly may be achieved.

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.

An example apparatus includes a buffer configured to. when enabled: obtain an input voltage: and provide the input voltage to a first boundary cell: and a second boundary cell configured to. when the apparatus is used in analog mode and a boundary scan occurs disable the buffer.