Abstract:
A three-stage differential ring oscillator circuit has a first differential stage, a second differential stage, and a third differential stage and generates six phases (two in each stage) used to form differential in-phase and quadrature-phase clock signals. A cross coupled inverter pair couples the first stage output signals. A second cross coupled inverter pair couples the second stage output signals. A third cross coupled inverter pair couples the third stage output signals. A first interpolator generates a first quadrature-phase clock signal using two phases (one from the positive portion of the second stage and one from the negative portion of the third stage) and a second interpolator generates a second quadrature-phase clock signal using two phases (one from the negative portion of the second stage and one from the positive portion of the third stage). Two phases from the first differential stage form the differential pair of in-phase clock signals.
Abstract:
Systems, apparatuses, and methods for implementing a deskewing method for a physical layer interface on a multi-chip module are disclosed. A circuit connected to a plurality of communication lanes trains each lane to synchronize a local clock of the lane with a corresponding global clock at a beginning of a timing window. Next, the circuit symbol rotates each lane by a single step responsive to determining that all of the plurality of lanes have an incorrect symbol alignment. Responsive to determining that some but not all of the plurality of lanes have a correct symbol alignment, the circuit symbol rotates lanes which have an incorrect symbol alignment by a single step. When the end of the timing window has been reached, the circuit symbol rotates lanes which have a correct symbol alignment and adjusts a phase of a corresponding global clock to compensate for missed symbol rotations.
Abstract:
Systems, apparatuses, and methods for implementing a negative resistance circuit for bandwidth extension are disclosed. Within a feedback path of a differential signal path, capacitors are placed on the inputs and outputs of a fully differential amplifier connecting to the differential signal path. In one embodiment, a circuit includes a fully differential amplifier and four capacitors. A first capacitor is coupled between a first signal path and a non-inverting input terminal of the amplifier and a second capacitor is coupled between the first signal path and a non-inverting output terminal of the amplifier. A third capacitor is coupled between a second signal path and an inverting input terminal of the amplifier and a fourth capacitor is coupled between the second signal path and an inverting output terminal of the amplifier. The first and second signal paths carry a differential signal.
Abstract:
In a system comprising a first device and a second device coupled via an interconnect, a method includes setting a rate of insertion of clock mismatch compensation symbols for a transmit port of the first device to one of a plurality of rates of insertion responsive to the second device having capability to compensate for a clock frequency mismatch. A device includes an interconnect interface comprising a transmit port and a receive port, and a configuration structure. The configuration structure comprises a capability field to store a value indicating whether the device has a capability to compensate for a clock frequency mismatch, and an enable field. The device further includes a packet control module to configure a rate of insertion of clock mismatch compensation symbols by the transmit port into a data stream responsive to a value stored at the enable field.
Abstract:
A method and apparatus is provided for outputting a reset signal during power-up until two conditions are satisfied. In one embodiment, the method and apparatus includes a voltage detector that provides a first output (“VO1”) when an output voltage of a regulator (“VREG”) exceeds a threshold voltage, thereby satisfying a first condition, a comparator receiving a first input voltage and a second input voltage, the comparator providing a second output (“VO2”) when the first input voltage exceeds the second input voltage, thereby satisfying a second condition, and a release circuit that outputs the reset signal unless the voltage detector provides VO1 while the comparator provides VO2.
Abstract:
Systems, apparatuses, and methods for implementing a combo scheme for direct current (DC) level shifting of signals are disclosed. A receiver circuit receives an input signal on a first interface. The first interface is coupled to a resistor in parallel with a capacitor which passes the input signal to a second interface. Also, the first interface is coupled to a first pair of current sources between ground and a voltage source, and the second interface is coupled to a second pair of current sources between ground and the voltage source. An op-amp drives the current sources based on a difference between a sensed common mode voltage and a reference voltage. Based on this circuit configuration, the receiver circuit is able to prevent baseline wander, perform a DC level shift of the input signal, and achieve linear equalization of the input signal.
Abstract:
Systems, apparatuses, and methods for implementing a periodic receiver clock data recovery scheme with dynamic data edge paths are disclosed. An IQ link calibration scheme performs a non-destructive data and edge path switch to determine an IQ offset without disturbing the data. A data path and an edge path pass through multiple stages of deserializers to widen the data path, with the deserializers clocked by clock divided versions of the original data and edge clocks. To initiate a calibration routine, the edge clock is aligned with the data clock, and then data and edge paths are swapped at a common point in a slower clock domain. The data path is then calibrated while the edge path carries the data signal. After the data path is calibrated, the edge and data paths are swapped back to the original configuration.
Abstract:
Systems, apparatuses, and methods for implementing a deskewing method for a physical layer interface on a multi-chip module are disclosed. A circuit connected to a plurality of communication lanes trains each lane to synchronize a local clock of the lane with a corresponding global clock at a beginning of a timing window. Next, the circuit symbol rotates each lane by a single step responsive to determining that all of the plurality of lanes have an incorrect symbol alignment. Responsive to determining that some but not all of the plurality of lanes have a correct symbol alignment, the circuit symbol rotates lanes which have an incorrect symbol alignment by a single step. When the end of the timing window has been reached, the circuit symbol rotates lanes which have a correct symbol alignment and adjusts a phase of a corresponding global clock to compensate for missed symbol rotations.
Abstract:
Systems, apparatuses, and methods for utilizing training sequences on a replica lane are described. A transmitter is coupled to a receiver via a communication channel with a plurality of lanes. One of the lanes is a replica lane used for tracking the drift in the optimal sampling point due to temperature variations, power supply variations, or other factors. While data is sent on the data lanes, test patterns are sent on the replica lane to determine if the optimal sampling point for the replica lane has drifted since a previous test. If the optimal sampling point has drifted for the replica lane, adjustments are made to the sampling point of the replica lane and to the sampling points of the data lanes.
Abstract:
Systems, apparatuses, and methods for utilizing training sequences on a replica lane are described. A transmitter is coupled to a receiver via a communication channel with a plurality of lanes. One of the lanes is a replica lane used for tracking the drift in the optimal sampling point due to temperature variations, power supply variations, or other factors. While data is sent on the data lanes, test patterns are sent on the replica lane to determine if the optimal sampling point for the replica lane has drifted since a previous test. If the optimal sampling point has drifted for the replica lane, adjustments are made to the sampling point of the replica lane and to the sampling points of the data lanes.