Memory controller for identifying the last valid page/segment in a physical block of a flash memory

摘要

Data is written in data areas (202) and information for correcting an error of the data and status information indicating that the data has been written are written in redundant areas (203) sequentially from the first page of a physical block (201). In the step of creating information to be written in the physical block (201), the redundant areas (203) of the pages are subjected to a binary search to temporarily identify a last valid page. Further, the contents of every area (the data areas and the redundant areas) of the temporarily identified last valid page and a page adjacent to the temporarily identified last valid page are checked to finally identify the last valid page and make a judgment as to whether or not an error page resulting from power-down exists.