Memory command delay balancing in a daisy-chained memory topology

Abstract

A daisy-chained memory topology wherein, in addition to the prediction of the timing of receipt of a response from a memory module (DIMM), the memory controller can effectively predict when a command sent by it will be executed by the addressee DIMM. By programming DIMM-specific command delay in the DIMM's command delay unit, the command delay balancing methodology according to the present disclosure 'normalizes' or 'synchronizes' the execution of the command signal across all DIMMs in the memory channel. By predicting command execution timing, the memory controller can efficiently control power profile of all the DRAM devices (or memory modules) on a daisy-chained memory channel. A separate DIMM-specific response delay unit in the DIMM is programmable to provide DIMM-specific delay compensation in the response path, further allowing the memory controller to accurately ascertain the timing of receipt of a response.