The disclosure describes novel methods and apparatuses for controlling a device's TCA circuit when the device exists in a JTAG daisy-chain arrangement with other devices. The methods and apparatuses allow the TCA test pattern set used during device manufacturing to be reused when the device is placed in a JTAG daisy-chain arrangement with other devices, such as in a customers system using the device. Additional embodiments are also provided and described in the disclosure.

In one embodiment, a method includes: powering on an integrated circuit (IC) and causing the IC to enter into a reset mode, where in the reset mode, a switch coupled between an oscillator of the IC and a reset pin is open; releasing the reset pin to cause the IC to enter into a non-reset mode, where in the non-reset mode the switch is closed to cause the clock signal to be superimposed on a reset signal at the reset pin; and determining, via a monitoring circuit coupled to the IC, the IC as functional in response to identifying the clock signal superimposed on the reset signal at the reset pin.

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.

An electrical circuit for testing primary internal signals of an ASIC. Only test pin is provided via which a selection can be made of a digital or analog signal to be observed. The electrical circuit includes a Schmitt trigger between the test pin and an output terminal of the electrical circuit. A test mode id activated when a switching threshold of the Schmitt trigger is exceeded. At least one sub-circuit is provided for the observation of a digital signal, having a resistor, an NMOS transistor, and an AND gate, at whose first input the digital signal is present. The resistor is between the test pin and the drain terminal of the NMOS transistor. The source terminal is connected to ground, and the gate terminal is connected to the output of the AND gate. The second input of the AND gate being connected to the output terminal of the electrical circuit.

Testing of integrated circuits is achieved by a test architecture utilizing a scan frame input shift register, a scan frame output shift register, a test controller, and a test interface comprising a scan input, a scan clock, a test enable, and a scan output. Scan frames input to the scan frame input shift register contain a test stimulus data section and a test command section. Scan frames output from the scan frame output shift register contain a test response data section and, optionally, a section for outputting other data. The command section of the input scan frame controls the test architecture to execute a desired test operation.

A testing circuit includes a command pad, a first circuit, a second circuit, a first latch, and a second latch. The command pad receives an operation command. The first integrated circuit performs a corresponding test operation according to the operation command and an internal selection signal. The second integrated circuit performs the corresponding test operation according to the operation command and an internal selection signal. The first latch provides the operation command to the first integrated circuit according to the internal selection signal. The second latch provides the operation command to the second integrated circuit according to the internal selection signal.

Testability of memory on integrated circuits is improved by connecting storage elements like latches in memory to scan chains and configuring memory for scan dump. The use of latches and similar compact storage elements to form scannable memory can extend the testability of high-density memory circuits on complex integrated circuits operable at high clock speeds. A scannable memory architecture includes an input buffer with active low buffer latches, and an array of active high storage latches, operated in coordination to enable incorporation of the memory into scan chains for ATPG/TT and scan dump testing modes.

Testability of memory on integrated circuits is improved by connecting storage elements like latches in memory to scan chains and configuring memory for scan dump. The use of latches and similar compact storage elements to form scannable memory can extend the testability of high-density memory circuits on complex integrated circuits operable at high clock speeds. A scannable memory architecture includes an input buffer with active low buffer latches, and an array of active high storage latches, operated in coordination to enable incorporation of the memory into scan chains for ATPG/TT and scan dump testing modes.

A semiconductor integrated circuit inputs and outputs signals regarding a test using two terminals, having a bidirectional terminal for input and output of data and an input terminal for input of a clock signal. A signal is output via the bidirectional terminal in accordance with an output control signal output from an output control circuit. The output control circuit performs control in synchronization with the clock signal to prevent data input to the bidirectional terminal and an output permission signal based on the output control signal from overlapping each other.

Testability of memory on integrated circuits is improved by connecting storage elements like latches in memory to scan chains and configuring memory for scan dump. The use of latches and similar compact storage elements to form scannable memory can extend the testability of high-density memory circuits on complex integrated circuits operable at high clock speeds. A scannable memory architecture includes an input buffer with active low buffer latches, and an array of active high storage latches, operated in coordination to enable incorporation of the memory into scan chains for ATPG/TT and scan dump testing modes.