Abstract: In a data-precessing receiver, a sampling circuit generates a plurality of samples of an incoming signal and stores the plurality of samples one after another in a first storage buffer. A first subset of the plurality of samples are transferred from the first storage buffer to a decoder circuit in response to each assertion of a first control signal, and a second subset of the plurality of samples are transferred from the first storage buffer to a tap weight update circuit in response to each assertion of a second control signal, the second strobe signal being asserted asynchronously with respect to the first control signal. The tap weight update circuit generates a plurality of updated tap weights based, at least in part, on the second subset of the plurality of samples.

Abstract: Described are transmitters with RAM-DAC based pre-emphasis filters that can be updated adaptively without interfering with data transmission. The memory within the RAM-DAC is divided into active and inactive memory locations, in which active memory locations are those to be accessed in the near future, and consequently cannot be updated (written to) at a given time due without inducing a read/write conflict. One embodiment monitors incoming memory addresses to find an adequate time window for a write to take place without a read interference. Another embodiment includes two memory blocks with similar address space, one of which may be updated as the other is used to for data transmission. Some embodiments employ a RAM-DAC with reduced memory size and complexity.

Abstract: An integrated circuit device includes one or more calibration paths including one or more devices. A signal generator is coupled to at least one calibration path and configured to provide the calibration path with a calibration signal having known characteristics. A controller is coupled to the signal generator and the calibration path and configured to adjust the signal generator and at least one parameter associated with at least one device in the calibration path.

Abstract: A signaling system includes a pre-emphasizing transmitter and an equalizing receiver coupled to one another via a high-speed signal path. The receiver measures the quality of data conveyed from the transmitter. A controller uses this information and other information to adaptively establish appropriate transmit pre-emphasis and receive equalization settings, e.g. to select the lowest power setting for which the signaling system provides some minimum communication bandwidth without exceeding a desired bit-error rate.

Abstract: A signaling system having an equalizing transmitter and equalizing receiver. The equalizing transmitter transmits a signal to a receive circuit. A first sampling circuit within the equalizing receiver samples the signal to determine whether the signal exceeds a first threshold, and a second sampling circuit within the equalizing receiver samples the signal to determine whether the signal exceeds a second threshold. A drive strength of the equalizing transmitter and a drive strength of an equalizing signal driver within the equalizer are adjusted based, at least in part, on whether the first signal exceeds the first and second thresholds.

Abstract: An integrated circuit device includes one or more calibration paths including one or more devices. A signal generator is coupled to at least one calibration path and configured to provide the calibration path with a calibration signal having known characteristics. A controller is coupled to the signal generator and the calibration path and configured to adjust the signal generator and at least one parameter associated with at least one device in the calibration path.

Abstract: A signaling system having an equalizing transmitter and equalizing receiver. The equalizing transmitter transmits a signal to a receive circuit. A first sampling circuit within the equalizing receiver samples the signal to determine whether the signal exceeds a first threshold, and a second sampling circuit within the equalizing receiver samples the signal to determine whether the signal exceeds a second threshold. A drive strength of the equalizing transmitter and a drive strength of an equalizing signal driver within the equalizer are adjusted based, at least in part, on whether the first signal exceeds the first and second thresholds.

Abstract: A differential amplifier and method of using same are disclosed. In one particular exemplary embodiment, the present invention may be realized as a circuit comprising a differential amplifier for receiving a differential input signal and generating a differential output signal, a comparator for generating an adjustment signal based at least in part upon the differential output signal, and a current controller for controlling current steering and at least one offset current in the differential amplifier based at least in part upon the adjustment signal and a current steering control signal.

Abstract: An integrated circuit having a receiver that selectively inhibits incoming data from being used to update adaptively generated controls. Sampling circuitry generates a plurality of samples of an incoming signal. Control circuitry generates an inhibit signal in either a first state or a second state according to whether the plurality of samples meets a randomness criterion. Tap weight update circuitry receives the inhibit signal from the control circuitry and updates a plurality of equalizer tap weights based on the plurality of samples if the inhibit signal is in the first state. The tap weight update circuitry refrains from updating the plurality of equalizer tap weights based on the plurality of samples if the inhibit signal is in the second state.

Abstract: In a data-precessing receiver, a sampling circuit generates a plurality of samples of an incoming signal and stores the plurality of samples one after another in a first storage buffer. A first subset of the plurality of samples are transferred from the first storage buffer to a decoder circuit in response to each assertion of a first control signal, and a second subset of the plurality of samples are transferred from the first storage buffer to a tap weight update circuit in response to each assertion of a second control signal, the second strobe signal being asserted asynchronously with respect to the first control signal. The tap weight update circuit generates a plurality of updated tap weights based, at least in part, on the second subset of the plurality of samples.

Abstract: A signaling system having an equalizing transmitter and equalizing receiver. The equalizing transmitter transmits a signal to a receive circuit. A first sampling circuit within the equalizing receiver samples the signal to determine whether the signal exceeds a first threshold, and a second sampling circuit within the equalizing receiver samples the signal to determine whether the signal exceeds a second threshold. A drive strength of the equalizing transmitter and a drive strength of an equalizing signal driver within the equalizer are adjusted based, at least in part, on whether the first signal exceeds the first and second thresholds.

Abstract: A receive circuit having a sampling circuit and a threshold generating circuit. The sampling circuit generates a first sample value having either a first state or a second state according whether an incoming signal exceeds a first threshold level, the first threshold level corresponding to a first threshold value. The threshold generating circuit combines a first control value and a second control value to generate the first threshold value and provides the first threshold value to the sampling circuit.

Abstract: A signaling system having first and second sampling circuits and an output driver circuit. The first sampling circuit samples a first signal generated by the output driver circuit to determine whether the first signal exceeds a first threshold. The second sampling circuit samples the first signal to determine whether the first signal exceeds a second threshold. The drive strength of the output driver circuit is adjusted based, at least in part, on whether the first signal exceeds the first and second thresholds, and the second threshold is adjusted based, at least in part, on whether the first signal exceeds the second threshold.

Abstract: Described are communication systems that convey differential and common-mode signals over the same differential channel. Noise-tolerant communication schemes use low-amplitude common-mode signals that are easily rejected by differential receivers, thus allowing for very high differential data rates. Some embodiments employ the common-mode signals to transmit backchannel signals for adjusting the characteristics of the differential transmitter. Backchannel control signals are effectively conveyed even if the forward channel transmitter is so maladjusted that the received differential data is unrecognizable. Systems in accordance with the above-described embodiments obtain these advantages without additional pins or communications channels, and are compatible with both AC-coupled and DC-coupled communications channels. Data coding schemes and corresponding data recovery circuits eliminate the need for complex, high-speed CDR circuits.

Abstract: A receive circuit for receiving a signal transmitted via an electric signal conductor. A first sampling circuit generates a first sample value that indicates whether the signal exceeds a first threshold level, and a second sampling circuit generates a second sample value that indicates whether the signal exceeds a second threshold level. A first select circuit receives the first and second sample values from the first and second sampling circuits and selects, according to a previously generated sample value, either the first sample value or the second sample value to be output as a selected sample value.

Abstract: Described are methods and circuits for margin testing digital receivers. These methods and circuits prevent margins from collapsing in response to erroneously received data, and can thus be used in receivers that employ historical data to reduce intersymbol interference (ISI). Some embodiments detect receive errors for input data streams of unknown patterns, and can thus be used for in-system margin testing. Such systems can be adapted to dynamically alter system parameters during device operation to maintain adequate margins despite fluctuations in the system noise environment due to e.g. temperature and supply-voltage changes. Also described are methods of plotting and interpreting filtered and unfiltered error data generated by the disclosed methods and circuits. Some embodiments filter error data to facilitate pattern-specific margin testing.