Abstract: A method of testing a data transmission and reception system comprises sending a test signal from a transmitter (14) of the system to a receiver (12) of the system, and analyzing the received signal. A duty cycle relationship is varied between the test signal and the timing signal used by the receiver of the system, and the effect of the duty cycle variation is analyzed. Varying the duty cycle relationship provides duty cycle distortion (DCD), and this can be considered as a form of embedded jitter insertion. This type of jitter can be measured relatively easily.

Abstract: ESD protection circuitry is disclosed. In one embodiment, an integrated circuit includes first and second sensor circuits. The first sensor circuit has a first resistive-capacitive (RC) time constant, while the second sensor circuit has a second RC time constant. The RC time constant of the first sensor circuit is at least one order of magnitude greater than that of the second sensor circuit. A first clamp transistor is coupled to and configured to be activated by the first sensor circuit responsive to the latter detecting an ESD event. A second clamp transistor is coupled to and configured to be activated by the second sensor circuit responsive to the latter detecting the ESD event.

Abstract: A method and apparatus for power glitch detection in IC's is disclosed. In one embodiment, a method includes a detection circuit in an IC detecting a voltage transient wherein a value of a supply voltage has at least momentarily fallen below a reference voltage value. Responsive thereto, the detection circuit may cause a logic value to be stored in a register indicating that the detection circuit has detected the supply voltage falling below the reference voltage. The IC may include a number of detection circuits coupled to the register, each of which may provide a corresponding indication of detecting the supply voltage falling below the reference voltage. The detection circuits may be placed at different locations, and thus reading the register may yield information indicating the locations where, if any, such voltage transients occurred.

Abstract: Embodiments of an apparatus for implementing a display port interface are disclosed. The apparatus may include a source processor and a sink processor coupled through an interface. The interface may include a primary link, and an auxiliary link. The source processor may be operable to send a wake-up command to the sink processor via the auxiliary link, which may indicate a change in frequency on the primary link. The source processor to the sink processor via the primary link may send initialization parameters, which may include a clock data recovery lock parameter and an idle parameter.

Abstract: ESD protection circuitry is disclosed. In one embodiment, an integrated circuit includes first and second sensor circuits. The first sensor circuit has a first resistive-capacitive (RC) time constant, while the second sensor circuit has a second RC time constant. The RC time constant of the first sensor circuit is at least one order of magnitude greater than that of the second sensor circuit. A first clamp transistor is coupled to and configured to be activated by the first sensor circuit responsive to the latter detecting an ESD event. A second clamp transistor is coupled to and configured to be activated by the second sensor circuit responsive to the latter detecting the ESD event.

Abstract: Embodiments of an apparatus for implementing a display port interface are disclosed. The apparatus may include a source processor and a sink processor coupled through an interface. The source processor may be operable to select a frequency from a continuous range of frequencies, and transmit data to the sink processor at the selected frequency. A phase lock circuit may be included in the sink processor. The phase lock circuit may be configured to generate a signal at the selected frequency dependent upon the transmitted data. The generated signal may be in phase with the transmitted data.

Abstract: A method and apparatus for power glitch detection in IC's is disclosed. In one embodiment, a method includes a detection circuit in an IC detecting a voltage transient wherein a value of a supply voltage has at least momentarily fallen below a reference voltage value. Responsive thereto, the detection circuit may cause a logic value to be stored in a register indicating that the detection circuit has detected the supply voltage falling below the reference voltage. The IC may include a number of detection circuits coupled to the register, each of which may provide a corresponding indication of detecting the supply voltage falling below the reference voltage. The detection circuits may be placed at different locations, and thus reading the register may yield information indicating the locations where, if any, such voltage transients occurred.

Abstract: An electronic device may contain clock circuits, transmitters, and other circuits that serve as sources of noise signals. The noise signals may be characterized by a noise spectrum. The noise spectrum produced by a noise source can be adjusted by adjusting spread spectrum clock circuitry in a clock circuit, by adjusting data scrambling circuitry in a transmitter circuit, or by making other dynamic adjustments to the circuitry of the electronic device. During operation of the electronic device, sensitive circuitry in the device such as wireless receiver circuitry may be adversely affected by the presence of noise from a noise source in the device. Based on information such as which receiver bands and/or channels are being actively received and target sensitivity levels for the receiver circuitry, control circuitry within the electronic device can determine in real time how to minimize interference between the noise source and the wireless receiver circuitry.

Abstract: Methods and apparatus for adjusting the operation of a display device so as to be at least within prescribed form factor or other constraints. In one embodiment of the invention, various operational parameters for a display element are adjusted based on considerations specific to high density form factor constraints. For example, in one such device, a Low Power DisplayPort (LPDP) device having a LPDP source and sink adjust the data rate of the visual data to minimize power consumption while still properly supporting display panel resolutions. In some embodiments, the LPDP source and sink may adjust the transceiver voltages to minimize power consumption. In an alternate embodiment, an LPDP device adjusts data rates to minimize the effects of platform noise. In another aspect of the invention, various display elements of a device coordinate quiescent (“quiet”) mode operation during periods of inactivity.

Abstract: A system and method for efficiently performing timing characterization of high-speed clocks signals with low-speed input/output pins. An integrated circuit includes a clock generator that generates a high-speed clock signal. A clock characterizer circuit receives the high-speed clock signal. The clock characterizer generates a corresponding low-speed clock signal. The generated low-speed clock signal is output through a low-speed general-purpose input/output (GPIO) pin for measurement. The generated low-speed clock signal is sent to a sequential element for staging. The staging of the generated low-speed clock signal is done with sequential elements that use a reverse polarity of a clock signal than the polarity used by a previous stage. The high-speed clock signal is used for the staging. The output of each stage is sent to a low-speed GPIO pin for measurement.

Abstract: Embodiments of an apparatus for implementing a display port interface are disclosed. The apparatus may include a source processor and a sink processor coupled through an interface. The source processor may be operable to select a frequency from a continuous range of frequencies, and transmit data to the sink processor at the selected frequency. A phase lock circuit may be included in the sink processor. The phase lock circuit may be configured to generate a signal at the selected frequency dependent upon the transmitted data. The generated signal may be in phase with the transmitted data.

Abstract: Embodiments of an apparatus for implementing a display port interface are disclosed. The apparatus may include a source processor and a sink processor coupled through an interface. The interface may include a primary link, and an auxiliary link. The source processor may be operable to send a wake-up command to the sink processor via the auxiliary link, which may indicate a change in frequency on the primary link. The source processor to the sink processor via the primary link may send initialization parameters, which may include a clock data recovery lock parameter and an idle parameter.

Abstract: A system and method for efficiently performing timing characterization of high-speed clocks signals with low-speed input/output pins. An integrated circuit includes a clock generator that generates a high-speed clock signal. A clock characterizer circuit receives the high-speed clock signal. The clock characterizer generates a corresponding low-speed clock signal. The generated low-speed clock signal is output through a low-speed general-purpose input/output (GPIO) pin for measurement. The generated low-speed clock signal is sent to a sequential element for staging. The staging of the generated low-speed clock signal is done with sequential elements that use a reverse polarity of a clock signal than the polarity used by a previous stage. The high-speed clock signal is used for the staging. The output of each stage is sent to a low-speed GPIO pin for measurement.

Abstract: An electronic device may contain clock circuits, transmitters, and other circuits that serve as sources of noise signals. The noise signals may be characterized by a noise spectrum. The noise spectrum produced by a noise source can be adjusted by adjusting spread spectrum clock circuitry in a clock circuit, by adjusting data scrambling circuitry in a transmitter circuit, or by making other dynamic adjustments to the circuitry of the electronic device. During operation of the electronic device, sensitive circuitry in the device such as wireless receiver circuitry may be adversely affected by the presence of noise from a noise source in the device. Based on information such as which receiver bands and/or channels are being actively received and target sensitivity levels for the receiver circuitry, control circuitry within the electronic device can determine in real time how to minimize interference between the noise source and the wireless receiver circuitry.

Abstract: Methods and apparatus for adjusting the operation of a display device so as to be at least within prescribed form factor or other constraints. In one embodiment of the invention, various operational parameters for a display element are adjusted based on considerations specific to high density form factor constraints. For example, in one such device, a Low Power DisplayPort (LPDP) device having a LPDP source and sink adjust the data rate of the visual data to minimize power consumption while still properly supporting display panel resolutions. In some embodiments, the LPDP source and sink may adjust the transceiver voltages to minimize power consumption. In an alternate embodiment, an LPDP device adjusts data rates to minimize the effects of platform noise. In another aspect of the invention, various display elements of a device coordinate quiescent (“quiet”) mode operation during periods of inactivity.

Abstract: A method of testing a data transmission and reception system comprises sending a test signal from a transmitter (14) of the system to a receiver (12) of the system, and analyzing the received signal. A duty cycle relationship is varied between the test signal and the timing signal used by the receiver of the system, and the effect of the duty cycle variation is analyzed. Varying the duty cycle relationship provides duty cycle distortion (DCD), and this can be considered as a form of embedded jitter insertion. This type of jitter can be measured relatively easily.

Abstract: A communication interface for use in an integrated circuit comprises a clock root circuit (110) configured to receive the clock reference signal and to generate a clock tree signal. A first lane circuit (220b) is coupled to the clock root circuit and configured to receive the clock tree signal and a select signal for selecting a clock signal for a first interface circuit. A second lane circuit (220a) is coupled to the first lane circuit and configured to receive the clock tree signal and a select signal for selecting a clock signal for a second interface circuit. In one embodiment, each lane circuit includes a buffer (222) configured to receive the clock tree signal and a multiplexer (228) configured to selectively deliver the clock tree signal to the interface circuit. Advantages of the invention include a modular construction of a communication interface having low clock skew.

Abstract: A multi-bit, programmable, modular digital frequency divider divides an input frequency by an m-bit integer divisor to produce an output frequency. The integer divisor re-initializes m-number of flip-flop stages with the divisor input at the end of every output clock. Each divisor bit is gated to a D-input through a respective data multiplexer controlled by a clock output. A run/initialize mode controller receives the input frequency and produces the divided output frequency and controls the timing of the re-initialization.

Abstract: There is a clock recovery circuit to correct the timing relationship between a data signal and clock signal. The clock recovery circuit comprises a phase detector having an input for receiving a clock signal having a period, an input for receiving a data signal, and an input for receiving a window signal. The window signal has a period equal to the period of the clock signal and phase difference of ?90° with respect to the clock signal. The phase detector generates an up output and a down output while maintaining a phase relationship of the up output and the down output in response to the phase relationship between the clock signal and the data signal.

Abstract: There is a clock recovery circuit to correct the timing relationship between a data signal and clock signal. The clock recovery circuit comprises a phase detector having an input for receiving a clock signal having a period, an input for receiving a data signal, and an input for receiving a window signal. The window signal has a period equal to the period of the clock signal and phase difference of −90° with respect to the clock signal. The phase detector generates an up output and a down output while maintaining a phase relationship of the up output and the down output in response to the phase relationship between the clock signal and the data signal.