Patent ID: 6639843
Filing Date: 2003-10-28
Classification: G11C

Abstract:
A semiconductor memory device having a nonvolatile memory portion of a block-unit erase type for sending and receiving data to and from a host section, the semiconductor memory device comprising:an arithmetic processing unit which entirely controls arithmetic processes of the semiconductor memory device and calculates logical block numbers from logical sector addresses given by the host section; the nonvolatile memory portion including a plurality of nonvolatile memories for dispersively storing data; and a conversion table storage portion which holds an address conversion table for converting the calculated logical block numbers into physical addresses serving as erase block numbers of the nonvolatile memories, wherein the arithmetic processing unit obtains the logical block numbers and offsets in logical blocks by calculating quotients and residuals, respectively, through dividing the logical sector addresses by a predetermined number of sectors possibly held in one erase block, wherein the address conversion table holds the erase block numbers of the nonvolatile memories corresponding to the calculated logical block numbers, wherein each of the nonvolatile memories is divided into a plurality of erase blocks, and data erase is performed in units of the erase blocks, and wherein pieces of address conversion table information are dispersively stored in each of the erase blocks, and the arithmetic processing unit reads out the logical block numbers from the erase blocks to thereby create the address conversion table on a RAM region of the conversion table storage portion.