Rambus Inc.

Arun Vaidyanath

Ian P Shaeffer

Sanku Mukherjee

Craig Edward Hampel

Yohan Usthavia Frans

Akash Bansal

Kishore Ven Kasamsetty

Simon Li

Todd W Bystrom

Ming Chu Li

Thomas J Giovannini

Abhijit Mukun Abhyankar

David A Secker

Ravindranath T Kollipara

Donald R Mullen

Adrian F Torres

An expandable memory system that enables a fixed signaling bandwidth to be configurably re-allocated among dedicated memory channels. Memory channels having progressively reduced widths are dedicated to respective memory sockets, thus enabling point-to-point signaling with respect to each memory socket without signal-compromising traversal of unloaded sockets or costly replication of a full-width memory channel for each socket.

Buffer IC with asymmetric memory module interfaces

Asymmetric-channel memory system

An integrated-circuit buffer component includes a control-side data interface configurably coupled to first and second memory-side data interfaces via internal conductors, the first data interface having twice as many input/output (I/O) transceivers as the second data interface. In a first memory system configuration in which only the first data interface is coupled to a memory module, steering circuitry couples all the internal data conductors exclusively to the I/O transceivers of the first data interface. In a second memory system configuration in which the first and second data interfaces are coupled to respective memory modules, the steering circuitry couples a first half of the internal data conductors exclusively to the I/O transceivers of the second data interface while a second half of the internal data conductors remains exclusively coupled to half the I/O transceivers of the first data interface.

Buffer component for asymmetric-channel memory system

A memory-control integrated circuit includes internal data conductors, steering circuitry and distinct first and second data interfaces, the first data interface having twice as many input/output (I/O) transceivers as the second data interface. In a first memory system configuration in which only the first data interface is coupled to a memory module, the steering circuitry couples all the internal data conductors exclusively to the I/O transceivers of the first data interface. In a second memory system configuration in which the first and second data interfaces are coupled to respective memory modules, the steering circuitry couples a first half of the internal data conductors exclusively to the I/O transceivers of the second data interface while a second half of the internal data conductors remains exclusively coupled to half the I/O transceivers of the first data interface.

Expandable asymmetric-channel memory system

A memory system includes a memory module which further includes a set of memory devices. The set of memory devices includes a first subset of memory devices and a second subset of memory devices. An address bus is disposed on the memory module, wherein the address bus includes a first segment coupled to the first subset and a second segment coupled to the second subset. An address signal traverses the set of memory devices in sequence. The memory system also includes a memory controller which is coupled to the memory module. The memory controller includes a first circuit to output a first control signal that controls the first subset, such that the first control signal and the address signal arrive at a memory device in the first subset at substantially the same time. The memory controller additionally includes a second circuit to output a second control signal that controls the second subset, such that the second control signal and the address signal arrive at a memory device in the second subset at substantially the same time.

Method and system for synchronizing address and control signals in threaded memory modules

The disclosed embodiments related to a clocked memory system which performs a calibration operation at a full-rate frequency to determine a full-rate calibration state that specifies a delay between a clock signal and a corresponding data signal in the clocked memory system. Next, the clocked memory system uses the full-rate calibration state to calculate a sub-rate calibration state, which is associated with a sub-rate frequency (e.g., &#xbd;, &#xbc; or &#x215b; of the full-rate frequency). The system then uses this sub-rate calibration state when the clocked memory system is operating at the sub-rate frequency. This calculation of the sub-rate state calibration states eliminates the need to perform an additional time-consuming calibration operation for each sub-rate.

Supporting calibration for sub-rate operation in clocked memory systems

A computing system having a memory riser sub-system. The computing system includes a motherboard with a memory module connector and a riser card inserted into the first memory module connector. A first mezzanine card is connected to the riser card. The first mezzanine card includes a first mezzanine memory module connector for a first memory module and a second mezzanine memory module connector for a second memory module. A memory channel electrically connects the memory controller to the first mezzanine memory module connector and the second mezzanine module connector via the motherboard, the first riser card and the first mezzanine card. The memory channel may be divided into a first data sub-channel connected to the first mezzanine memory module connector and a second data sub-channel connected to the second mezzanine memory module connector.

Memory capacity expansion using a memory riser

The disclosed embodiments related to a clocked memory system which performs a calibration operation at a full-rate frequency to determine a full-rate calibration state that specifies a delay between a clock signal and a corresponding data signal in the clocked memory system. Next, the clocked memory system uses the full-rate calibration state to calculate a sub-rate calibration state, which is associated with a sub-rate frequency (e.g., 1/2, 1/4 or 1/8 of the full-rate frequency). The system then uses this sub-rate calibration state when the clocked memory system is operating at the sub-rate frequency. This calculation of the sub-rate state calibration states eliminates the need to perform an additional time-consuming calibration operation for each sub-rate.

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San Jose, CA, United States of America

Arun Vaidyanath