Emc Corporation

Home Director, Inc.

Jeffrey T McLamb

Jeffrey A Hatley

Larson J Isely

Larry M Hicks

Gary Deen

William J Grasty

Todd J Honnigford

Stephen Lye

Tracking several open data connections is difficult with a large number of connections. Checking for timeouts in software uses valuable processor resources. Employing a co-processor dedicated to checking timeouts uses valuable logic resources and consumes extra space. In one embodiment, a finite state machine implemented in hardware increases the speed connections can be checked for timeouts. The finite state machine stores a last accessed time stamp for each connection in a memory, and loops through the memory to compare each last accessed time stamp with a current time stamp of the system minus a global timeout value. In this manner, the finite state machine can efficiently find and react to timed out connections.

Hardware method for detecting timeout conditions in a large number of data connections

A running disparity computation predictor is configured to analyze a frame of data, a control value, and an input tracking value and generate a predicted output tracking value. A frame selector is configured to generate an encoded frame of data based on this predicted output tracking value. A frame insertion module is configured to insert the encoded frame of data into a data stream wherein the predicted output tracking value matches an output tracking value generated by the data stream. This combination of elements can bypass an encoder built into a Hard IP block or proprietary hardware when the running disparity value is required to select control words.

Running disparity computation predictor

A clock domain crossing technique that uses a circular buffer toggled by clocks from the two domains with output metastability protection. The resulting output is a pair of enable signals that may be used to pass data between the two clock domains. In one embodiment, a set of storage devices is connected in a circular buffer arrangement. A first subset of the storage devices is clocked by a signal from a first clock domain and a second subset of the flip flops is clocked by a signal taken from a second clock domain. Respective output circuits generate enable signals to be used for transferring data between domains. In some implementations, a pulse is stored and registered by at least two of the storage devices in the first domain before being passed to the devices in the second domain. In other embodiments, the output circuits may include a pair of D flip flops, each clocked by a respective one of the first or second domain signals. In specific arrangements, an output flip flop takes its data input from a logical AND of signals output from a flip flop within its associated domain, to ensure that the enable signal is asserted for only a single output clock cycle, and/or a second flip flop uses a logical AND of its input and inverted output states to avoid metastable conditions.

Simple circular asynchronous clock domain crossing technique for digital data

Telephone line distribution apparatus are provided that permit easy user-selection of primary and secondary telephone lines without requiring physical rewiring of RJ plugs or receptacles. A telephone line distribution apparatus includes a first RJ connector, one or more second RJ connectors, and a switching device that allows a subscriber to designate which of a plurality of incoming telephone lines is the subscriber's primary line and secondary line. A switching device has various user-selectable configurations. When in a first configuration, a first incoming telephone line becomes the subscriber primary telephone line at one or more of the second RJ connectors. When the switching device is in a second configuration, a second incoming telephone line becomes the subscriber primary telephone line at one or more of the second RJ connectors. Additional incoming telephone lines can be designated as primary or secondary telephone lines in a similar manner. Telephone line distribution apparatus may also include DSL signal splitting capabilities.

Growing community of inventors

Raleigh, NC, United States of America

Jeffrey T McLamb