Field of the Invention
The present invention relates to a data maintenance method, and in particular to a data maintenance method related to data reading. 
Description of the Related Art
Flash memory is considered a non-volatile data-storage device that uses electrical methods to erase and program itself.  NAND Flash, for example, is often used in memory cards, USB flash devices, solid state devices, eMMCs, and other memory devices. 
Flash memory such as NAND Flash uses a multiple-block structure to store data, wherein the flash memory uses floating gate transistors.  The floating gates of the floating gate transistor may catch electronic charges for storing data.  However, the floating gates may lose their electronic charges due to various operations and the various environmental parameters of the flash memory, which can lead to the problem of data retention.