US Patent 9275699 Memory with alternative command interfaces

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.