Directed auto-refresh synchronization

Abstract

In a directed auto-refresh (DARF) mode, refresh commands are issued by a controller, and refresh row and bank addresses are maintained internally to a memory module. A bank address counter internal to the memory is initialized to a first predetermined value upon entering DARF mode. The memory refreshes the currently addressed bank in response to a DARF command, and increments the bank address counter in a predetermined sequence. The controller tracks the bank address, and may issue one or more memory access commands while a DARF operation is being performed, if the memory access and the refresh are directed to different banks. Upon exiting a self-refresh mode, the bank address counter assumes a second predetermined value. The second predetermined value may be fixed, or may be n+1, where n is the value of the bank address counter when self-refresh mode is initiated.

Dependencies are inferred from the claim text.