International Business Machines Corporation

Gary Alan Peterson

Frank David Ferraiolo

Robert J Reese

Daniel Mark Dreps

Patrick James Meaney

Christopher W Steffen

Luiz Carlos Alves

Christopher N Oelsner

Kevin Charles Gower

Martin Eckert

Hubert Harrer

Andrew A Turner

Frank William Angelotti

Kenneth Lee Christian

Rohan A Jones

Michael D Campbell

Neil A Malek

Dermot Weldon

A technique relates to dynamic time-domain reflectometry (TDR). A machine spares a bad lane in a bus. The bad lane is taken offline. TDR is dynamically executed on the bad lane while the bus is still in operation. A defect is isolated using results of the TDR.

Dynamic time-domain reflectometry analysis for field replaceable unit isolation in a running system

A computer system includes a processor, and the processor includes at least one interface for communicating with an electronic component. Each of the at least one interface has a set of interface settings. The computer system further includes a memory containing machine executable instructions. Execution of the instructions causes the processor to: monitor communications traffic on the at least one interface; store, eye distribution data acquired during the monitoring of the communications traffic in a database; compare the eye distribution data to a set of predetermined criteria; and generate a set of updated interface settings if the eye distribution does not satisfy the set of predetermined criteria.

Updating interface settings for an interface

A mechanism for de-skewing and aligning data bits sent between two chips on an elastic interface. On the receiving end of an elastic interface, the eye of each data bit within a clock/data group is delayed by less than a bit time to align the eyes with the nearest clock edge of a received clock signal. In addition to aligning the eyes of the individual data bits with the nearest clock edge, IAP patterns are used to determine the amount of further delay needed to line up the individual data beats from each data bit. If the data beats for the data bits are not aligned, all but the slowest data beat are delayed to align the data beats for all bits. The additional delay is achieved using sample latches that result in a delayed signal with less jitter. As a result of having less jitter, the received, de-skewed, and aligned clock/data group can be forwarded to the operative portion of the receiving chip at an increased frequency.

Elastic interface de-skew mechanism

Methods and apparatus are disclosed for aligning received data bits in elastic interface systems. Depending upon which one of several alignment modes is selected, data bits can be loaded into FIFO latches on rising clock edges if the data was sent on rising clock edges, on falling clock edges if the data was sent on falling clock edges, or on the nearest clock edge if minimum latency is desired. Alternatively, data bits can be delayed by one or more bit times before loading into FIFO latches to reduce the elastic interface system's sensitivity to drift. The present invention permits a user to trade off factors related to for latency, drift, and skew by choosing among different alignment modes in an elastic interface system.

Alignment mode selection mechanism for elastic interface

A method and apparatus for de-skewing and aligning digital data received over an elastic interface bus is disclosed. Upon receiving the data, it is sent through a programmable delay line. While in the programmable delay line, the data is sampled at three points within the data's eye pattern. The three sampling points are dynamically adjusted to maximize coverage of the data's eye pattern. During the adjustment of the sampling points to optimally cover the data's eye pattern, delayed data is sampled from an alternate sampler to prevent sampling from the functional sampler while the delay in the primary sampler is adjusted. Sampling from the alternate sampler while changing the sampling points of the functional sampler serves to reduce glitches that may occur by sampling the functional sampler while its sampling parameters are changed. The method and apparatus allow for alternate eye tracking and wrap around eye tracking.

Dynamic recalibration mechanism for elastic interface

A phase detector for use in conjunction with a delay locked loop is provided. Programmable delay elements insert an adjustable delay in a received data stream. The programmable delays stress the setup and hold times of the incoming data. Phase detector sampling logic detects the phase difference between a nominal center of the data window, and the limits on the setup (early) edge of the data value window, and the hold time limit (late time) edge of the data valid window (&ldquo;guardbands&rdquo;). A data signal arriving earlier than an early guardband or later than a late guardband may not be correctly sampled, and a guardband failure may be said to have occurred. A state machine detects such guardband errors and provides corrective feedback signals.

Phase detector

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Rochester, MN, United States of America

Gary Alan Peterson