SOFTWARE REFRESHED MEMORY DEVICE AND METHOD

A software refreshed memory device comprises a plurality of memory cells that must be periodically refreshed to avoid losing data. Preferably, the memory cells can avoid losing data even though the time interval between successive memory refresh operations is relatively long, as compared to the time interval between successive memory refresh operations in a conventional volatile memory device, such as a DRAM. A processor can perform periodic memory refresh operations by executing a set of memory refresh instructions implemented in software, rather than in hardware. Accordingly, the memory device can advantageously be simplified, because the need for memory refresh circuitry and for a unique refresh control signal are advantageously eliminated. Moreover, the processor executing the memory refresh instructions can typically perform more sophisticated algorithms, as compared to memory refresh circuitry implemented in hardware, for determining when to perform a memory refresh operation. For example, the processor can determine whether each individual memory cell needs to be refreshed, thereby advantageously avoiding performing unnecessary refresh operations on memory cells that do not need to be refreshed.