Nvidia Corporation

Michael Hopgood

Vishal Mehta

Hitendra Dutt

David Wyatt

Wei-Je Robert Huang

Robert Huang

Mark Taylor

Dennis K Ma

Huabo Chen

Yu Chang

Hungse Cha

Samuel Vincent

Hakki Ozguc

Feroze Karim

Srikanth Devarapalli

A method comprises selecting a starting point on a map of equalization coefficients and measuring an eye height of a signal transmitted using the set of equalization coefficients associated with the starting point and an eye height associated with each adjacent point on the map relative to the starting point. The eye height associated with an adjacent point is based on a signal transmitted using the set of equalization coefficients associated with the adjacent point. The method also comprises walking on the map in a first direction from the starting point to the adjacent point associated with the greatest eye height, wherein the eye height associated with the adjacent point is greater than or equal to the eye height associated with the starting point.

Equalization coefficient search algorithm

In a system according to one embodiment of the present disclosure, the system comprises a first device, a second device, a communications link, and a memory. The memory stores instructions that when executed by the system perform a method of communications link training. This method comprises requesting a speed change to a second speed for the first device communicating with the second device at a first speed via the communications link. A saved set of parameters are accessed for at least one of the first device and the second device. A first training cycle is performed for the first device and the second device at the second speed using the saved set of parameters for the at least one of the first device and second device. The reuse of parameters from a previous successful equalization training cycle reduces the time required to perform equalization training.

System and method for detecting reuse of an existing known high-speed serial interconnect link

Systems and methods for stabilizing clock data recovery (CDR) by filtering the abrupt phase shift associated with data pattern transition in the input signal. The CDR circuit includes a data pattern detector coupled to a data pattern filter. The data pattern detector is capable of detecting the data patterns of the input signal. Accordingly, the data pattern filter can selectively generate a filter indication indicating to freeze or suppress the CDR phase caused by data pattern transition. The filter indication can be incorporated to a phase error signal, a gain function, and/or the control voltage driving the VCO.

Clock data recovery circuit

In an apparatus according to one embodiment of the present disclosure, a communications link comprises a first device and a second device communicating with each other via the communications link at a plurality of different speeds. However, prior to communicating via the communications link for the first time at a second speed, the first device and second device complete a first training cycle at the second speed. Further, during this first training cycle for the second speed, the first training cycle for the second speed will pause before the first training cycle at the second speed completes, and the first device and second device communicate at a first speed for a period of time before returning to the paused first training cycle at the second speed. When the paused first training cycle for the second speed continues, the first training cycle for the second speed will continue where it had paused.

Method and apparatus for interleaving bursts of high-speed serial interconnect link training with bus data transactions

A method comprises performing a first pass test over a plurality of sets of equalization coefficients to filter the plurality of sets of equalization coefficients to produce one or more filtered sets of equalization coefficients. Each filtered set of equalization coefficients meets a first predetermined threshold. The method also comprises performing a second pass test over the one or more filtered sets of equalization coefficients to determine a final set of equalization coefficients that meets a second predetermined threshold. The second pass test produces more accurate results than the first pass test.

Multipass approach for performing channel equalization training

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San Jose, CA, United States of America

Michael Hopgood