International Business Machines Corporation

Stephen P Glancy

Warren Edward Maule

John Stanley Bialas, Jr

Gary A Van Huben

David D Cadigan

Kyu-hyoun Kim

Kevin M Mcilvain

Jeremy R Neaton

Diyanesh B Chinnakkonda Vidyapoornachary

Edgar Rolando Cordero

Anuwat Saetow

Saravanan Sethuraman

Hillery C Hunter

Charles Arthur Kilmer

Jacob D Sloat

Frank LaPietra

Richard D Wheeler

Vipin Patel

William Vincent Huott

Gary A Tressler

Adam J McPadden

Kyu-Hyoun Kim

Ryan Patrick King

Yelena M Tsyrkina

Siva Pr Boosa

Kevin McIlvain

A memory system for storing data is disclosed, the memory system including a plurality of memory devices configured to store data, each memory device having a plurality of bits, the memory devices configured and associated to work together as a rank to respond to a request; a memory control circuit associated with the plurality of memory devices and configured to output command and control signals to the plurality of memory devices; a detector for detecting a bit error in an operation; and a controller for remapping the bit error to a spare bit lane in response to the detector detecting the bit error.

Efficient and selective sparing of bits in memory systems

A method and/or system for checking the bus/interface between a host and a memory system during memory access operations includes a memory system having one or more of the data memory devices and a spare memory device; providing a bus/interface between a host and the memory system; selecting information on a per memory device basis to associate with a spare memory device; disassociating the selected information from the one or more data memory devices and associating the selected information with the spare memory device; adding Cyclical Redundancy Check (CRC) code to the one or more data memory devices from which the selected information was disassociated; transferring the CRC code and information over the bus and interface between the host and the memory system; and checking the bus interface with the CRC code added to the one or more data memory devices.

Method and apparatus to reduce bandwidth overhead of CRC protection on a memory channel

A computer-implemented method for calibrating DRAM is provided. A non-limiting example of the computer-implemented method includes reading, by a processor, system configuration information and disabling, by the processor, one or more steps in a list of calibration steps to be performed based on the system configuration information to leave a list of remaining calibration steps. Based on a determination that two or more remaining calibration steps are co-dependent, the method configures, by the processor, a single calibration step that encapsulates the co-dependent algorithm and places, by the processor, the single calibration step in a list of steps to be called. The method then provides, by the processor, the list of steps to be called.

Hardware abstraction in software or firmware for hardware calibration

An aspect includes generating, within a first memory device of a memory system, a plurality of event-based information associated with activity in the memory system. The event-based information is stored in a reserved portion of the first memory device. The event-based information is provided to a memory controller of the memory system corresponding with an access of a memory row across a plurality of memory devices of the memory system associated with the event-based information.

Internally-generated data storage in spare memory locations

A computer-implemented method for command-address-control calibration of a memory device includes starting, via a processor, a controller clock for the memory device, releasing, via the processor, a reset on the memory device, running, via the processor, a calibration pattern for calibrating the memory device by placing the memory device in calibration mode, where the calibration pattern is initiated prior to an initialization of the memory device, calibrating, via the processor, the memory device with a calibration setting based on the calibration pattern, and initializing the memory device based on the calibration setting.

Memory device command-address-control calibration

A double data rate (DDR) memory controller writes a test pattern to a location in a DDR memory for a coarse calibration test, delayed by a first number of cycles set in a tunable write delay setting. The DDR memory controller simulates a single data rate (SDR) mode for the coarse calibration test by only comparing every other read beat of the test pattern read from the DDR memory, delayed by a second number of cycles set in tunable read delay setting, wherein every other read beat is latched for a full cycle. The DDR memory controller, responsive to every other read beat of the test pattern matching an expected result, sets the first number of cycles and the second number of cycles as coarse calibration settings for a DRAM.

Simulating a single data rate (SDR) mode on a dual data rate (DDR) memory controller for calibrating DDR memory coarse alignment

Embodiments herein describe a memory system that includes a DRAM module with a plurality of individual DRAM chips. In one embodiment, the DRAM chips are per DRAM addressable (PDA) so that each DRAM chip can use a respective reference voltage (VREF) value to decode received data signals (e.g., DQ or CA signals). During runtime, the VREF value can drift away from its optimal value set when the memory system is initialized. To address possible drift in VREF value, the present embodiments perform VREF calibration dynamically. To do so, the memory system monitors a predefined criteria to determine when to perform VREF calibration. To calibrate VREF value, the memory system may write transmit data and then read out the test data to determine the width of a signal eye using different VREF values. The memory system selects the VREF value that results in the widest signal eye.

Reference voltage calibration in memory during runtime

In an example, a method includes monitoring a memory bus for one or more commands sent by a memory controller to a memory device and determining whether the one or more commands have a value indicating an operation mode of the memory device. Information associated with the one or more commands may be assessed based on the operation mode, and the information may be stored to one or more registers of the memory controller. The operation mode may be a per dynamic random access memory (DRAM) addressability (PDA) mode, a per buffer addressability (PBA) mode, or a per rank mode. Accessing the information may include a first set of configuration values in response to the value indicating the PDA mode or the PBA mode, and a second set of configuration values in response to the value indicating the per rank mode.

Per-DRAM and per-buffer addressability shadow registers and write-back functionality

An aspect includes providing communication links from a memory controller to contents of a plurality of bit locations in a plurality of memory devices. A failing bit location in the plurality of bit locations is detected by the memory controller. A replacement bit location for the failing bit location is selected and a replacement communication link to the replacement bit location is provided by the memory controller. A request to access contents of the failing bit location received after the selecting and providing the replacement communication link is performed by accessing contents of the replacement bit location via the replacement communication link.

Bitwise sparing in a memory system

A system and method for efficient data eye training reduces the time and resources spent calibrating one or more memory devices. A temporal calibration mechanism reduces the time and resources for calibration by reducing the number tests needed to sufficiently determine the boundaries of the data eye of the memory device. For one or more values of the voltage reference, the temporal calibration mechanism performs a minimal number of tests to find the edges of the data eye for the hold and setup times.

Efficient calibration of a data eye for memory devices

In an example, a system includes a memory controller that includes a plurality of memory components. The system also includes a memory controller configured to receive a plurality of memory settings to be applied to the plurality of memory components. The memory controller is configured to, based on the received memory settings, transmit a first command to the plurality of memory components, the first command causing each memory component of the plurality of memory components to be configured to a first memory setting. The memory controller is configured to, based on the received memory settings, transmit a second command to a subset of the plurality of memory components after transmitting the first command, the second command causing each memory component of the subset to be configured to a second memory setting.

Efficient configuration of memory components

A calibration controller tests an electronic circuit to identify an initial read check with a read delay, an initial write check with a write delay, and an initial command, address, control (CAC) check with a CAC delay indicated as passing. Responsive to the initial read check, the initial write check, and the initial CAC check indicated as passing, for each setting of the read delay, the write delay, and the CAC delay, the calibration controller iteratively performs concurrently, a write test with the write delay, a read test with the read delay, and a CAC test with the CAC delay on the electronic circuit over the range of conditions while simultaneously adjusting the write delay, the read delay, and the CAC delay for each iteration until one or more of a read edge, a write edge, and a CAC edge are detected.

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Poughkeepsie, NY, United States of America

Stephen P Glancy