Abstract: An active termination circuit for a differential receiver includes a first receiver element configured to receive a first component of a differential signal, a second receiver element configured to receive a second component of a differential signal, a common mode measurement element configured to receive the differential signal and generate a transmit common mode signal (Vcm) representing an average value of the differential signal, and a receiver (RX) common mode signal node. The termination circuit also comprises an active element configured to receive the transmit common mode signal (Vcm) and provide an output to the receiver common mode signal node, the output configured to drive the value of the signal at the receiver common mode signal node to the value of the transmit common mode signal (Vcm), and a capacitive element coupled to the receiver common mode signal node in parallel with the active element.

Abstract: An active termination circuit for a differential receiver includes a first receiver element configured to receive a first component of a differential signal, a second receiver element configured to receive a second component of a differential signal, a common mode measurement element configured to receive the differential signal and generate a transmit common mode signal (Vcm) representing an average value of the differential signal, and a receiver (RX) common mode signal node. The termination circuit also comprises an active element configured to receive the transmit common mode signal (Vcm) and provide an output to the receiver common mode signal node, the output configured to drive the value of the signal at the receiver common mode signal node to the value of the transmit common mode signal (Vcm), and a capacitive element coupled to the receiver common mode signal node in parallel with the active element.

Abstract: Techniques for multi-wire encoding with an embedded clock are disclosed. In one particular exemplary embodiment, the techniques may be realized as a transmitter component. The transmitter component may comprise at least one encoder module to generate a set of symbols, each symbol being represented by a combination of signal levels on a set of wires. The transmitter component may also comprise at least one signaling module to transmit one or more of the symbols over the set of wires according to a transmit clock. The transmitter component may additionally comprise control logic to restrict transmission of first and second subsets of the set of symbols to respective first and second portions of a clock cycle of the transmit clock, such that a signal differential among at least two of the set of wires exhibits a switching behavior that has a same frequency as the transmit clock.

Abstract: Techniques for multi-wire encoding with an embedded clock are disclosed. In one particular exemplary embodiment, the techniques may be realized as a transmitter component. The transmitter component may comprise at least one encoder module to generate a set of symbols, each symbol being represented by a combination of signal levels on a set of wires. The transmitter component may also comprise at least one signaling module to transmit one or more of the symbols over the set of wires according to a transmit clock. The transmitter component may additionally comprise control logic to restrict transmission of first and second subsets of the set of symbols to respective first and second portions of a clock cycle of the transmit clock, such that a signal differential among at least two of the set of wires exhibits a switching behavior that has a same frequency as the transmit clock.

Abstract: A timing circuit for generating a timing signal having a predetermined relationship with a reference signal. The timing circuit includes a locked loop for generating the recovered clock signal, comparing the phase of the reference signal to the phase of the timing signal, and adjusting the phase of the timing signal based on the comparison; and a PVT (Process-Voltage-Temperature) line operatively associated with the locked loop so that PVT drift in the PVT line counters PVT drift in the locked loop.

Abstract: A circuit and method for synchronized clocking of components such as registers. Registers are clocked by individual component clock signals having the same frequency but potentially different phases due to differing propagation delays. Separate component clock signals are received by registers are brought into phase by evaluating the phases of the component clock signals at the registers, and synchronizing the component clock signal of each register to that of the previous register in a sequence.

Abstract: A timing circuit for generating a timing signal having a predetermined relationship with a reference signal. The timing circuit includes a locked loop for generating the recovered clock signal, comparing the phase of the reference signal to the phase of the timing signal, and adjusting the phase of the timing signal based on the comparison; and a PVT (Process-Voltage-Temperature) line operatively associated with the locked loop so that PVT drift in the PVT line counters PVT drift in the locked loop.

Abstract: Self-timed interfaces and methods are provided for interfacing different timing domains. These self-timed interfaces receive a strobe signal from a component operating under a first clock domain. A first signal path of the self-timed interface couples the strobe signal to a receiver that samples data of data line under control of the strobe signal. A second signal path of the self-timed interface couples the strobe signal to an interface circuit through a hysteresis-based element. The interface circuit, under control of an output of the hysteresis-based element along with a clock signal that originates under a second clock domain, generates an interface enable signal for use in controlling data transfers between the different clock domains.

Abstract: A high-speed communication interface manages a parallel bus having N bus lines. N+1 communication lines are established. A maintenance operation is performed on one of the N+1 communication lines, while N of the N+1 communication lines is available for data from the N line bus. The communication line on which the maintenance operation is performed, is changed after the operation is complete, so that all of the N+1 communication lines are periodically maintained, without interfering with communications on N of the N+1 communication lines.

Abstract: Systems and methods for masking strobe signals in strobe-based systems are provided below. These strobe-masking systems receive a strobe signal from a component operating under one clock domain and in turn generate a masked version of the strobe signal. Components of a host system use the masked strobe signal to receive or transfer data from the clock domain of the strobe signal through a mesochronous clock domain crossing into a different clock domain.

Abstract: An apparatus and method provides prediction of BER for an interface between ICs, such as a processor and a memory device, without using special test equipment. A known data pattern or PRBS is transmitted to a receiver, which compares the received data values with expected data values to determine if a bit error has occurred in an embodiment of the present invention. A center of data eye and the edge of the data eye are sampled (over sampled) in order to determine if a bit error has occurred in an alternate embodiment of the present invention. A first counter is used to count the total number of bits sampled and the second counter is used to count the number of errors that occurred in the total number of bits sampled. In an embodiment of the present invention, the first and second counters are logarithmic counters that include overflow protection. The counter values are output to a processing device to perform the BER calculation in an embodiment of the present invention.

Abstract: An apparatus having a dual rail regulated reference loop. The reference loop includes a delay circuit powered by upper and lower supply voltages to generate a plurality of reference clock signals, and a voltage regulation circuit to adjust the upper and lower supply voltages according to a phase difference between a selected pair of the reference clock signals.

Abstract: A locked loop circuit having a clock hold function. The locked loop circuit includes a select circuit, phase mixing circuit, hold signal generator and latch circuit. The select circuit selects one of a plurality of phase values in response to a select signal, and the phase mixing circuit generates a first clock signal having a phase angle according to the selected phase value. The hold signal generator asserts a hold signal in response to a transition of the select signal, and the latch circuit latches the state of the first clock signal in response to assertion of the hold signal.

Abstract: An integrated circuit device having a select circuit, a summing circuit and a phase mixer. The select circuit selects one of a plurality of offset values as a selected offset. The summing circuit sums the selected offset with a phase count value, the phase count value indicating a phase difference between a reference clock signal and one of a first plurality of clock signals. The phase mixer combines the first plurality of clock signals in accordance with the sum of the selected offset and the phase count value to generate an output clock signal.

Abstract: A circuit and method for synchronized clocking of components such as registers. Registers are clocked by individual component clock signals having the same frequency but potentially different phases due to differing propagation delays. Separate component clock signals are received by registers are brought into phase by evaluating the phases of the component clock signals at the registers, and synchronizing the component clock signal of each register to that of the previous register in a sequence.

Abstract: A high-speed communication interface manages a parallel bus having N bus lines. N+1 communication lines are established. A maintenance operation is performed on one of the N+1 communication lines, while N of the N+1 communication lines is available for data from the N line bus. The communication line on which the maintenance operation is performed, is changed after the operation is complete, so that all of the N+1 communication lines are periodically maintained, without interfering with communications on N of the N+1 communication lines.

Abstract: A circuit and method for synchronized clocking of components such as registers. Registers are clocked by individual component clock signals having the same frequency but potentially different phases due to differing propagation delays. Separate component clock signals are received by registers are brought into phase by evaluating the phases of the component clock signals at the registers, and synchronizing the component clock signal of each register to that of the previous register in a sequence.

Abstract: An integrated circuit device having a select circuit, a summing circuit and a phase mixer. The select circuit selects one of a plurality of offset values as a selected offset. The summing circuit sums the selected offset with a phase count value, the phase count value indicating a phase difference between a reference clock signal and a first plurality of clock signals. The phase mixer combines the first plurality of clock signals in accordance with the sum of the selected offset and the phase count value to generate an output clock signal.

Abstract: A technique for voltage level shifting in input circuitry is disclosed. In one exemplary embodiment, the technique may be realized as a method for voltage level shifting input signals. This method may comprise receiving first and second input signals having first and second voltage levels, respectively, and then differentially amplifying the first and second input signals so as to generate first and second amplified voltage signals having first and second amplified voltage levels, respectively, wherein the first and second amplified voltage signals are substantially complementary. This method may then comprise reducing the first and second amplified voltage levels of the first and second amplified voltage signals so as to generate first and second level shifted amplified voltage signals having first and second level shifted amplified voltage levels, respectively.

Abstract: A circuit and method for level-shifting an input signal are disclosed that provide for level-shifting of a the input signal where an external voltage level is greater than an internal voltage of the signal. In the present invention, the input signal is compared to a reference signal to produce a differential current signal reflecting the logic level of the input signal. The differential current signal is reflected through a pair of current mirrors operating from the external voltage level to drive a pair of resistive loads. Each of the resistive loads is coupled in series with a current sink between the internal supply voltage and a ground voltage. As a result, the input signal may be received and level-shifted with gain even when the internal supply voltage is less than twice a transistor threshold voltage without introducing significant distortion to the received signal.