Rambus Inc.

Pradeep Batra

Steven Cameron Woo

Lawrence Lai

Brian S Leibowitz

Rick A Rutkowski

Frederick Abbott Ware

Richard E Perego

Trung Am Diep

Chi-Ming Yeung

Wayne Frederick Ellis

Liji Gopalakrishnan

Lei Luo

Vlad Fruchter

Shahram Nikoukary

Jonghyun Cho

Anand Jai

Jared L Zerbe

Stefanos Sidiropoulos

Paul G Davis

James A Gasbarro

John Bradly Dillon

Karnamadakala Krishnamohan

A memory controller integrated circuit includes a clock signal generator circuit configured to generate a plurality of strobe signals. The memory controller integrated circuit further includes a memory interface circuit coupled to the clock signal generator circuit, the memory interface circuit configured to transmit the plurality of strobe signals to a memory module, wherein each of the plurality of strobe signals is offset with respect to an adjacent strobe signal, and transmit a plurality of data signals to the memory module, wherein a first subset of the plurality of data signals comprises a first nibble and is phase aligned with a first strobe signal of the plurality of strobe signals, and wherein a second subset of the plurality of data signals comprises a second nibble and is phase aligned with a second strobe signal of the plurality of strobe signals.

Signal skew in source-synchronous system

A memory space of a module connected to a memory controller via a memory interface may be used as a command buffer. Commands received by the module via the command buffer are executed by the module. The memory controller may write to the command buffer out-of-order. The memory controller may delay or eliminate writes to the command buffer. Tags associated with commands are used to specify the order commands are executed. A status buffer in the memory space of the module is used to communicate whether commands have been received or executed. Information received via the status buffer can be used as a basis for a determination to re-send commands to the command buffer.

Communication via a memory interface

A memory system includes a CPU that communicates commands and addresses to a main-memory module. The module includes a buffer circuit that relays commands and data between the CPU and the main memory. The memory module additionally includes an embedded processor that shares access to main memory in support of peripheral functionality, such as graphics processing, for improved overall system performance. The buffer circuit facilitates the communication of instructions and data between CPU and the peripheral processor in a manner that minimizes or eliminates the need to modify CPU, and consequently reduces practical barriers to the adoption of main-memory modules with integrated processing power.

Methods and systems for mapping a peripheral function onto a legacy memory interface

A memory controller encrypts contents of a page frame based at least in part on a frame key associated with the page frame. The memory controller generates a first encrypted version of the frame key based at least in part on a first process key associated with a first process, wherein the first encrypted version of the frame key is stored in a first memory table associated with the first process. The memory controller generates a second encrypted version of the frame key based at least in part on a second process key associated with a second process, wherein the second encrypted version of the frame key is stored in a second memory table associated with the second process, the first process and the second process sharing access to the page frame using the first encrypted version of the frame key and the second encrypted version of the frame key, respectively.

Process authenticated memory page encryption

A first integrated circuit (IC) has an adjustable delay circuit and a first interface circuit. A first clock signal is provided to the adjustable delay circuit to produce a delayed clock signal provided to the first interface circuit. A second IC has a supply voltage sense circuit and a second interface circuit that transfers data with the first IC. The supply voltage sense circuit provides a noise signal to the first IC that is indicative of noise in a supply voltage of the second IC. The adjustable delay circuit adjusts a delay of the delayed clock signal based on the noise signal. In other embodiments, edge-colored clock signals reduce the effects of high frequency jitter in the transmission of data between integrated circuits (ICs) by making the high frequency jitter common between the ICs. In other embodiments, a supply voltage is used to generate clocks signals on multiple ICs.

Techniques for adjusting clock signals to compensate for noise

Described are systems and method for protecting data and instructions shared over a memory bus and stored in memory. Independent and separately timed stream ciphers for write and read channels allow timing variations between write and read transactions. Data and instructions can be separately encrypted prior to channel encryption to further secure the information. pad generators and related cryptographic circuits are shared for read and write data, and to secure addresses. The cryptographic circuits can support variable data widths, and in some embodiments memory devices incorporate security circuitry that can implement a shared-key algorithm using repurposed memory circuitry.

Methods and circuits for securing proprietary memory transactions

Disclosed herein is a method and system for calibrating line drive currents in systems that generate data signals by varying line drive currents and that interpret the data signals by comparing them to one or more reference voltages. The calibration includes varying the line drive current at a transmitting component. At different line drive currents, a receiver reference voltage is varied while the transmitting component transmits data to a receiving component. At each line drive current, the system records the highest and lowest receiver reference voltages at which data errors do not occur. The system then examines the recorded high and low receiver reference voltages to determine a desirable line drive current.

Bus line current calibration

A memory system includes physical memory devices or ranks of memory devices that can be set to reduced power modes. In one embodiment, a hardware memory controller receives memory instructions in terms of a logical address space. In response to the relative usages of different addresses within the logical address space, the memory controller maps the logical address space to physical memory in a way that reduces the number of memory devices that are being used. Other memory devices are then set to reduced power modes. In another embodiment, an operating system maintains a free page list indicating portions of physical memory that are not currently allocated. The operating system periodically sorts this list by group, where each group corresponds to a set or rank of memory devices. The groups are sorted in order from those receiving the heaviest usage to those receiving the lightest usage. When allocating memory, the memory is allocated from the sorted page list so that memory is preferentially allocated from those memory devices that are already receiving the highest usage.

Growing community of inventors

Santa Clara, CA, United States of America

Pradeep Batra