A non-volatile semiconductor memory device and/or a data processing system include a non-volatile memory array having a plurality of memory blocks and a write-protection control circuit that controls access to blocks of memory based on a start block address and an end block address. The write-protection control circuit may store start and end block addresses of an unlock region of the non-volatile memory array, and selectively activate a write enable signal according to the relationship between a write address and the start and end block addresses.