Embodiments of a memory controller are described. This memory controller includes signal connectors, which are electrically coupled to a communication path that includes multiple links, and an interface circuit, which is electrically coupled to the signal connectors. In a first operating mode, the interface circuit communicates with a first memory device via the communication path using spatial multiplexing, in which there are dedicated command/address links and dedicated data links in the communication path. Moreover, in a second operating mode, the interface circuit communicates with a second memory device via the communication path using time multiplexing, in which at least some of the links in the communication path time interleave command/address information and data.