Memory system

摘要

A memory system (10) is disclosed, which comprises a flash-EEPROM nonvolatile memory (11) having a plurality of memory cells that have floating gates and in which data items are electrically erasable and writable, a cache memory (13) that temporarily stores data of the flash-EEPROM nonvolatile memory (11), a control circuit (12, 14) that controls the flash-EEPROM nonvolatile memory (11) and the cache memory (13), and an interface circuit (16) that communicates with a host, in which the control circuit functions to read data from a desired target area to-be-determined of the flash-EEPROM nonvolatile memory and detect an erased area to determine a written area/unwritten area by using as a determination condition whether or not a count number of data “0” of the read data has reached a preset criterion count number.

主权项

1. A memory system comprising:
a nonvolatile memory comprising a plurality of storage areas each including memory portions that each store one of a first data item and a second data item; a cache memory that temporarily stores data read from the nonvolatile memory; a control circuit that controls the nonvolatile memory and the cache memory, the control circuit comprising a counter that is configured to count the number of the first data items; and an interface circuit that communicates with a host, wherein the control circuit is configured to execute: a first determination in which it is determined whether data is written in each of the storage areas, counting a number of first data items stored in the memory portions in each of the storage areas; and a second determination in which the storage areas are sequentially read to determine a boundary between a first storage area in which data is written and a second storage area in which data is not written.