An address and command port interface selectively enables JTAG TAP domain operations and Trace domain operations within an IC. The port carries TMS and TDI input and TDO output on a single pin and receives a clock signal on a separate pin. The addressable two pin interface loads and updates instructions and data to the TAP domain within the IC. The instruction or data update operations in multiple ICs occur simultaneously. A process transmits data from an addressed target device to a controller using data frames, each data frame comprising a header bit and data bits. The logic level of the header bit is used to start, continue, and stop the data transmission to the controller. A data and clock signal interface between a controller and multiple target devices provides for each target device to be individually addressed and commanded to perform a JTAG or Trace operation.

A circuit screening system includes a target circuit under test, a power circuit, and a clock generating circuit. The target circuit under test receives a first testing signal in a first period, and a second testing signal in a second period, and the first testing signal is different from the second testing signal. The power circuit provides a supply voltage to the target circuit under test, wherein a voltage level of the supply voltage maintains at a first voltage level in the first period, is pulled up to a second voltage level and back to the first level after the first period, and maintains at the first voltage level in a second period after the first period. The clock generating circuit provides a clock signal to the target circuit under test, wherein the clock signal has different profiles in the first period and the second period.

A reference voltage buffer circuit includes an operational amplifier, a capacitor switching module, a first transistor and a second transistor. The operational amplifier includes two input terminals and an output terminal, where the two input terminals receive an input reference voltage and a feedback voltage, respectively. A gate electrode of the first transistor is coupled to the capacitor switching module, and a source electrode of the first transistor provides the feedback voltage. A gate electrode of the second transistor is coupled to the capacitor switching module, and a source electrode of the second transistor provides an output reference voltage. In addition, the operational amplifier generates a stable control voltage to the gate electrodes of the first transistor and the second transistors via the capacitor switching module while the output terminal of the operational amplifier is not directly connect to the gate electrodes of the first transistor and the second transistors.

A test circuit measures both the rising edge delay and the falling edge delay associated with a logic cell. The test circuit includes a flip-flop type ring oscillator with two groups of logic cells connected in series in the oscillation path. A first multiplexor switches the ring oscillator between a rising edge and a falling edge mode. A second multiplexer causes the second group of logic cells to be included or excluded from the oscillation path. By measuring the oscillation period in the various modes, the rising edge and falling edge delays can be individually calculated.

Disclosed embodiments relate to sensing states and changes of states of a signal and sensors for the same, including but not limited to, autonomous sensors. Such sensor may include an analog signal threshold detection circuit, a state detection circuit, and a measurement circuit. The analog signal threshold detection circuit may be configured to alternately assert and de-assert a threshold detected indication in response to an input signal and a state thereof. The state detection circuit may be configured to generate a signal state indication about a state of the input signal. The measurement circuit may be configured to generate a measurement in response to assertions of the threshold detected indication and the signal state indication, such as a count, a slew rate, or a frequency. In some embodiments, disclosed sensors may have programmable thresholds for sensing the signal states and changes therein.

A status of one or more components of a battery monitor circuit can be evaluated, such as to validate operation of the monitor circuit. In an example, a battery monitor circuit can be evaluated by providing a first test signal to a battery voltage measurement circuit that is coupled to a battery. A first analog-to-digital converter (ADC) circuit can be configured to receive a first voltage signal from the battery voltage measurement circuit in response to the first test signal. A processor circuit can be configured to validate the first ADC circuit by evaluating a correspondence between the first test signal and the received first voltage signal. One or more other ADC circuits in the battery monitor circuit can be validated by cross-checking measurement results with information from the first ADC circuit.

A chip testing method includes: a data receiving window corresponding to each chip to be tested is determined; a time adjustment parameter corresponding to each chip to be tested is determined according to the data receiving window corresponding to each chip to be tested and a data input window preset for a test machine is determined; an actual input time point corresponding to each chip to be tested is determined according to the time adjustment parameter corresponding to each chip to be tested; and data is inputted to each chip to be tested at the actual input time point corresponding to the each chip to be tested, to enable each chip to be tested to receive the data inputted by the test machine in the data receiving window corresponding to the each chip to be tested.

A device for monitoring a critical path of an integrated circuit includes a replica of the critical path formed by sequential elements mutually separated by delay circuits that are programmable though a corresponding main multiplexer. A control circuit controls delay selections made by each main multiplexer. A sequencing module operates to sequence each sequential element using a main clock signal by delivering, in response to a main clock signal, respectively to the sequential elements, secondary clock signals that are mutually time shifted in such a manner as to take into account the propagation time inherent to the main multiplexer.

A self-test built in a conditional access chip is provided. The conditional access chip decrypts video data by using a plurality of logic units. The self-test circuit includes: a storage circuit, storing test data and comparison data; and a control circuit, coupled to the logic units, controlling the logic units to receive a clock to perform a test, reading the test data from the storage circuit, inputting the test data to a scan chain formed by the logic units according to the clock, and comparing output data of the scan chain with the comparison data to obtain a test result.

A multi-bit flip-flop includes: a single scan input pin to receive a scan input signal, a plurality of data input pins to receive first and second data input signals, a first scan flip-flop to select one of the scan input signal and the first data input signal as a first selection signal in response to a scan enable signal and to latch the first selection signal to provide a first output signal, a second scan flip-flop to select one of an internal signal corresponding to the first output signal and the second data input signal as a second selection signal in response to the scan enable signal and to latch the second selection signal to provide a second output signal, and a plurality of output pins to output the first and second output signals, wherein scan paths of the first and second scan flip-flops are connected to each other.