Abstract: An interpolative divider includes a look ahead sigma delta modulator circuit to generate divide values according to a divide ratio. A plurality of M storage elements are coupled to the sigma delta modulator to store the divide values, M being at least 2. A selector circuit selects the respective divide values and supplies the divide values to a portion of an interpolative divider circuit, the portion including a divider and a phase interpolator. The interpolative divider generates an output clock signal having a first clock period that may be determined by the first and second divide values. The M storage elements are loaded by a clock signal that is slower than the output clock signal by at least half.

Abstract: In order to increase test coverage of integrated circuits with multiple clock domains, during a capture portion of a scan test, the functional clock signals, associated with a respective one of the clock domains are synchronized to ensure back and forth capture between the faster and slower clock domain. Each of the plurality of clock signals is generated such that an active edge of each faster clock signal occurs one clock period of the faster clock signal before an active edge of each slower clock signal.

Abstract: During scan testing a voltage regulator is programmed to supply a first voltage to logic under test during a shift portion of the scan test, a second voltage during a first portion of a capture portion of the scan test and at least a third voltage during a second portion of the capture portion of the scan test. The availability of a programmable voltage regulator during shift and capture portions of scan testing allows a less stressful voltage to be used during a shift portion of the scan test to reduce shift failures and allows various voltages to be used during capture portions of the scan testing as a surrogate for testing at different temperatures and to provide more flexibility in testing margins.

Abstract: A phase-locked loop uses an edge detect circuit to detect an edge of an input clock signal. The detected edge is used to digitally align an initial edge of the feedback signal with the input clock signal to the PLL so that the feedback signal is substantially aligned with the input clock signal. The edge alignment of the feedback signal may be performed at startup or in response to loss of lock/input clock switching. By aligning the feedback signal the input clock signal based on the edge detect, faster lock occurs.

Abstract: An interpolative divider includes a look ahead sigma delta modulator circuit to generate divide values according to a divide ratio. A plurality of M storage elements are coupled to the sigma delta modulator to store the divide values, M being at least 2. A selector circuit selects the respective divide values and supplies the divide values to a portion of an interpolative divider circuit, the portion including a divider and a phase interpolator. The interpolative divider generates an output clock signal having a first clock period that may be determined by the first and second divide values. The M storage elements are loaded by a clock signal that is slower than the output clock signal by at least half.

Abstract: A phase-locked loop uses an edge detect circuit to detect an edge of an input clock signal. The detected edge is used to digitally align an initial edge of the feedback signal with the input clock signal to the PLL so that the feedback signal is substantially aligned with the input clock signal. The edge alignment of the feedback signal may be performed at startup or in response to loss of lock/input clock switching. By aligning the feedback signal the input clock signal based on the edge detect, faster lock occurs.

Abstract: A receiver includes a first terminal for receiving an RF signal having a frequency of less than approximately 60 MHz, a second terminal, and a receive path having an input coupled to the first terminal and an output for providing a demodulated RF signal. The receiver further includes a detector coupled to the receive path for detecting a signal parameter in the RF signal and a controller coupled to the detector and to the second terminal. The controller provides the multiplex signal in a tuning state to the second terminal to selectively provide one of a first RF signal and a second RF signal to the first terminal and to determine at least one of a first parameter of the first RF signal and a second parameter of the second RF signal. The controller provides the multiplex signal in an operating state based on the first parameter and the second parameter.

Abstract: A fractional-N divider receives an input signal and supplies a divided signal divided in accordance with an integer divide control signal determined from a divide ratio. A phase interpolator is coupled to the fractional-N divider to adjust a phase of the divided signal according to a fractional portion of the divide ratio. The apparatus, responsive to a request for a frequency adjustment of the generated signal in a programmable number of steps, is configured to adjust the frequency of the generated signal from a beginning frequency to an ending frequency in the programmable number of steps by adjusting the supplied divide ratio at each step.

Abstract: A fractional-N divider receives an input signal and supplies a divided signal divided in accordance with an integer divide control signal determined from a divide ratio. A phase interpolator is coupled to the fractional-N divider to adjust a phase of the divided signal according to a fractional portion of the divide ratio. The apparatus, responsive to a request for a frequency adjustment of the generated signal in a programmable number of steps, is configured to adjust the frequency of the generated signal from a beginning frequency to an ending frequency in the programmable number of steps by adjusting the supplied divide ratio at each step.

Abstract: A high resolution programmable clock synthesizer that is portable across processes and, thus, process independent is disclosed herein. The clock synthesizer provides a dynamic solution, in that the frequency of the desired clock signal is programmable. Initially, a control unit monitors the input clock signal and the output clock signal to provide the appropriate control signals to a delay string buffer and a fine tuning unit based upon the desired frequency of the output clock signal. While the delay string buffer provides a coarse adjustment to the input clock signal, fine control is provided through the use of the fine tuning unit which further adjustments to the input clock signal. This clock synthesizer exceeds the accuracy of known delay line oscillators by using drive strengths of the in-loop elements to provide a better granularity for the clock synthesizer. Thereby, high resolution is achieved through the use of coarse adjustment and fine adjustment.

Abstract: Multimode, multiline data transfer systems and methods of operating the same. In one embodiment, one system includes: (1) a bus interface for a bus, the bus interface having a start line driver, a clock line driver and a data line driver and (2) control circuitry coupled to the bus interface and configured to cause the start line driver to establish a selected one of plural data communication protocols over the bus, the clock line driver configured to serve as a further data line driver when the selected one is based on pulse-width modulation.

Abstract: A high resolution programmable clock synthesizer that is portable across processes and, thus, process independent is disclosed herein. The clock synthesizer provides a dynamic solution, in that the frequency of the desired clock signal is programmable. Initially, a control unit monitors the input clock signal and the output clock signal to provide the appropriate control signals to a delay string buffer and a fine tuning unit based upon the desired frequency of the output clock signal. While the delay string buffer provides a coarse adjustment to the input clock signal, fine control is provided through the use of the fine tuning unit which further adjustments to the input clock signal. This clock synthesizer exceeds the accuracy of known delay line oscillators by using drive strengths of the in-loop elements to provide a better granularity for the clock synthesizer. Thereby, high resolution is achieved through the use of coarse adjustment, fine adjustment and addition of dither.

Abstract: Multimode, multiline data transfer systems and methods of operating the same. In one embodiment, one system includes: (1) a bus interface for a bus, the bus interface having a start line driver, a clock line driver and a data line driver and (2) control circuitry coupled to the bus interface and configured to cause the start line driver to establish a selected one of plural data communication protocols over the bus, the clock line driver configured to serve as a further data line driver when the selected one is based on pulse-width modulation.