Intel Corporation

Richard S Jensen

David Stewart Dunning

Chamath Abhayagunawardhana

Kenneth Drottar

Ken Drottar

Sanjay Dabral

Robert C Glenn

Jie Ni

Santanu Chaudhuri

Joseph E Pelissier

Michael M DeSmith

Davied S Dunning

According to some embodiments an apparatus comprising a vote generator, a vote governor, and a local clock controller is provided. The vote generator generates votes based on a local clock signal and transitions in a stream of received data. The vote governor receives the generated votes and discards at least some of the votes. The local clock controller adjusts the local clock signal based on a generated vote that has not been discarded.

Local receive clock signal adjustment

Conventional receiver architectures are based on either frequency/phase tracking or oversampling. Both receiver types typically employ sensitive analog circuits, which create noise, consume power and utilize valuable space in their implementation. The invention adopts a novel approach to phase/frequency tracking that utilizes the edges or zero crossings of the input data waveform to effectively track the remote transmitter clock phase/frequency. This methodology minimizes the use of analog circuitry, thereby reducing the noise domain and the substrate space required for implementation of a tracking device.

Method and apparatus for receiving data based on tracking zero crossings

When signaling over cables or other media having significant return impedance, it is generally more efficient to use two conductors to carry two simultaneous bi-directional signals differentially, rather than utilizing unidirectional communications. Bi-directional communications increases the aggregate bandwidth of a pair of conductors. A conversion circuit converts unidirectional signaling between an edge-based receiver and a transmitter to simultaneous differential bi-directional signaling. A receiver for receiving data includes an edge processor operative to make decisions using edges of a received data stream and a communication circuit coupled to the edge processor. The communication circuit is operative to convert communications with the edge processor from a first format, such as unidirectional signaling, to a second format, such as differential bi-directional signaling.

Differential simultaneous bi-directional receiver

A phase interpolator interpolates between a plurality of clock phases using a plurality of switching legs coupled to a common output. Each switching leg includes a pair of differential switching transistors each having a gate and two additional terminals, one of which is coupled to said common output. The gates are coupled to respective ones of the plurality of clock phases and their complements. Tails couple the other terminals of said switching transistors to ground. Each tail made up of a plurality of transistors. A load coupling the common output to a voltage.

Phase interpolator to interpolate between a plurality of clock phases

A method of recovering data from a modulated data signal includes tracking a transmitted clock with a plurality of locally-generated clock phases, estimating an average phase of previously detected edges, registering a pulse edge in the received stream of data at a transition phase corresponding to one of the plurality of locally-generated clock phases, determining whether a first symbol was received multiple times consecutively prior to the registered pulse edge, and using the determination of whether the first symbol was received multiple times consecutively in a receiver decision process.

Method and apparatus for receiving data

Briefly, in accordance with one embodiment of the invention, a method of synchronizing two ends of a bi-directional network communication path includes the following. A sequence of predetermined characters are repeatedly transmitted from an end of a bi-directional network communication path if reception is lost at that end. Synchronization or resynchronization occurs from both ends if the sequence of predetermined characters is received at the other end.

Method and apparatus for synchronizing a network link

A switch circuit having low charge dumping characteristics includes multiple parallel connected switching transistors and one or more associated cancellation transistors. The switching transistors perform basic switching functions within the switch circuit in response to a digital signal. During transitions of the digital signal, the switching transistors dump charge on an output node thereof due to parasitic capacitances within the devices. The cancellation transistor(s) dumps charge of an opposite polarity on the output node to cancel the charge dumped by the switching transistors. Two switching transistors are used for each cancellation transistor so that equal sized devices can be used throughout the switch circuit.

Low charge-dump transistor switch

A tracking data receiver which can compensate for deterministic jitter is disclosed. The device utilizes a history of past data received to determine which of multiple samples taken within a bit period to utilize. Due to deterministic jitter that can occur in data signal communication, the delay of waveform development varies with the ratio of 0's to 1's transmitted prior to the bit period being observed. The present invention exploits the predictable nature of the deterministic jitter to decide which sample to choose.

Method and apparatus for a tracking data receiver compensating for deterministic jitter

Link-based flow control requires each link transmitter to retain packets until such time as they are acknowledged by the link receiver. Depending on the type of acknowledge, the transmitter will then either retry or de-allocate the packets. To improve throughput, the present invention includes an optimistic transmitter, which transmits packets without knowing the state of the receiver buffer. By so doing, the present invention improves the latency caused by delays in transit time between nodes. Furthermore, single acknowledgments are used to indicate successful receipt of multiple packets. Single negative acknowledgments are used to indicate successful receipt of all data between a last acknowledged data packet and a packet associated with the negative acknowledgment, which was received with errors.

Method and apparatus for controlling the flow of data between servers using optimistic transmitter

An error detection technique uses a cumulative error detecting code (such as a cumulative CRC checksum or the like). At the source node (transmitter side) an error detecting code of a previous cell is stored. The next cell to be transmitted is received and the error detecting code of the previous cell is appended to the next cell. A next error detecting code is calculated as a function of at least a portion of the next cell to be transmitted and the previous error detecting code appended thereto. The previous error detecting code appended to the next cell is replaced with the next error detecting code, and the next cell including the next error detecting code appended thereto is transmitted. In this manner, the cumulative error detecting code is calculated over the current cell and a previous error detecting code. Thus, the cumulative error detecting code can be used to detect bit errors in each individual cell as well as to detect one or more missing or dropped cells.

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Aloha, OR, United States of America

Richard S Jensen