Wear compensation in a non-volatile memory flash - without the necessity of free blocks

摘要

PROBLEM TO BE SOLVED: To solve such a problem that in a nonvolatile memory such as a flash memory, when the number of times of rewriting for some block becomes more, a spare block to be substituted must be prepared, and consequently, a chip area is increased largely.;SOLUTION: This device comprises a nonvolatile memory device 1 composed of a number of times of rewriting monitoring circuit 2a having memories storing the number of times of rewriting for each block of a memory part and a read-out register and of a block address setting changing circuit 2b for converting a specified block address to inside block specification conforming to corresponding information read out from a memory for changing block address setting; a memory device 7 for refuging block data to be changed; and a controller 11 for controlling so that when the number of times of rewriting of a block to be rewritten reaches to the prescribed value, a block of the minimum number of times of rewriting is made destination of change, this data is erased after refuging, the number of times of rewriting is increased, corresponding information of the memory for changing setting is updated, and the original write-in data is written in the origin of change and the destination of change.;COPYRIGHT: (C)2005,JPO&NCIPI