Texas Instruments Corporation

John Joseph Seibold

Sudhanshu Khanna

Dirk Preikszat

Atul Ramakant Lele

Elie Torbey

Vinay B Jayaram

A clock oscillator control circuit is provided. The clock oscillator control circuit includes a signal processor configured to receive a composite clock request signal and output an altered composite clock request signal. The clock oscillator control circuit also includes logic circuitry configured to receive the altered composite clock request signal from the signal processor and a clock oscillator valid signal from a clock oscillator, and to output set and reset signals based on the altered composite clock request signal and the clock oscillator valid signal. The clock oscillator control circuit further includes a set-reset latch configured to receive the set and reset signals from the logic circuitry and to output an enable signal to the clock oscillator.

Clock oscillator control circuit

A clock oscillator control circuit is provided. The clock oscillator control circuit includes a signal processor configured to receive a composite clock request signal and output a altered composite clock request signal. The clock oscillator control circuit also includes logic circuitry configured to receive the altered composite clock request signal from the signal processor and a clock oscillator valid signal from a clock oscillator, and to output set and reset signals based on the altered composite clock request signal and the clock oscillator valid signal. The clock oscillator control circuit further includes a set-reset latch configured to receive the set and reset signals from the logic circuitry and to output an enable signal to the clock oscillator.

A test system in an integrated circuit includes at least one boundary scan cell. The boundary scan cell includes a first storage element and a second storage element connected in series with the first storage element. The boundary scan cell also includes test logic configured to provide a test completion signal indicative of completion of a respective test based on a comparison of an output of the first storage element relative to test value (TVALUE). The output of the first storage element is provided to the input of the second storage element unchanged during a first operating state and, depending on the test completion signal, an inverted version of the output of the first storage element can be provided to the input of the second storage element during a second operating state. A bi-directional element is connected to receive the output of the second storage element and to feed the output of the second storage element back to an input of the first storage element.

Built in self test for input/output characterization

An integrated circuit apparatus includes a switching circuit that provides respective signal paths to permit a mission signal, a test signal, and a boundary scan test signal to share an output terminal. The signal path associated with the mission signal imposes a smaller switching delay than do the signal paths associated with the test and boundary scan test signals.

Reducing mission signal output delay in IC having mission and test modes

A test system in an integrated circuit includes a boundary scan cell. The boundary scan cell includes a first storage element and a second storage element connected in series with the first storage element. The boundary scan cell also includes initialization logic connected between an output of the first storage element and an input of the second storage element. The initialization logic provides the output of the first storage element to the input of the second storage element unchanged during a first operating state, and provides an inverted version of the output of the first storage element to the input of the second storage element during a second operating state. A bi-directional element is connected to receive an output of the second storage element, the bi-directional element feeding the output of the second storage element to an input of the first storage element, such that capture of a state change at the output of the first storage element at the output of the first storage element is facilitated during the second operating state.

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John Joseph Seibold