METHOD AND APPARATUS FOR FORCING IDLE CYCLES TO ENABLE REFRESH OPERATIONS IN A SEMICONDUCTOR MEMORY

摘要

Method and apparatus for operating a memory system having a plurality of memory blocks. The method includes: periodically asserting a timing signal; asserting a refresh pending signal in each memory block when the asserted timing signal is received; within each memory block, performing a refresh operation if the refresh pending signal in the memory block is asserted and an idle cycle exists in the memory block; within each memory block, asserting a refresh acknowledge signal if a refresh operation is performed in the memory block; within each memory block, de-asserting the refresh pending signal in the memory block if the refresh acknowledge signal is asserted in the memory block; asserting a refresh forcing signal if the refresh pending signal in any of the memory blocks is asserted when the timing signal is asserted; and forcing an idle cycle in all memory blocks if the refresh forcing signal is asserted.