Memory with alternative command interfaces
AssigneeRambus Inc.
InventorsLiji Gopalakrishnan, Ian Shaeffer, Yi Lu
Life of this patent
Estimating the term…
Abstract
A memory device or module selects between alternative command ports. Memory systems with memory modules incorporating such memory devices support point-to-point connectivity and efficient interconnect usage for different numbers of modules. The memory devices and modules can be of programmable data widths. Devices on the same module can be configured select different command ports to facilitate memory threading. Modules can likewise be configured to select different command ports for the same purpose.
Claims19
A memory controller to control memory devices disposed on a memory module, the memory devices each having a selectable first command port and a selectable second command port, the memory controller comprising:
- circuitry to configure a first subset of the memory devices to receive first commands via first command ports at each respective memory device in the first subset of the memory devices, and to configure a second subset of the memory devices to receive second commands via second command ports at each respective memory device in the second subset of the memory devices;
- a first command interface to connect to the first command port of each memory device of the first subset of the memory devices;
- and
- a second command interface to connect to the second command port of each memory device of the second subset of the memory devices.
A method of communicating memory commands and data to memory devices disposed on a memory module, the memory devices each having a first command port adapted to receive the memory commands, a second command port adapted to receive the memory commands, a multiplexer to select only one of the first and second command ports, and mode memory to control the multiplexer to select the one of the first and second command ports, the method comprising:
- issuing a mode command to each of the memory devices to load the mode memories and control the multiplexers, the mode command causing each of the multiplexers to select the one of the first and second command ports;
- issuing first commands to the first command port of each of the memory devices of a first subset of the memory devices disposed on the memory module;
- and
- issuing second commands to the second command port of each of the memory devices of a second subset of the memory devices.
A memory controller to issue memory commands and communicate data to memory devices disposed on a memory module, the memory devices each having a first command port adapted to receive the memory commands from the memory controller, a second command port adapted to receive the memory commands from the memory controller, a multiplexer to select only one of the first and second command ports, and mode memory to control the multiplexer to select the one of the first and second command ports, the memory controller comprising:
- a first command interface to connect to the first command port of each of the memory devices of a first subset of the memory devices disposed on the memory module;
- and
- a second command interface to connect to the second command port of each of the memory devices of a second subset of the memory devices;
- the memory controller issuing a mode command to each of the memory devices to load the respective mode memories and control the multiplexers.
Dependencies are inferred from the claim text.