memory devices are adapted for direct interface or virtual integration with a processor or other logic device through a local bus and isolated from a system bus . such memory devices are capable of lower power requirements and reduced size due in part to the elimination of certain redundant circuitry . direct interfacing through the local bus facilitates the elimination or reduction of input / output buffer circuitry by eliminating the need to step up to and step down from typical system bus voltage levels . communication between the memory device and a separate logic device occurs across the local bus at voltage levels compatible with internal logic levels of the memory device .