| abstract |
[PROBLEMS] To provide a multi-value storage type nonvolatile storage device capable of minimizing an increase in circuit scale and realizing highly accurate writing, reading and erasing operations in a short time. SOLUTION: The threshold value of a memory cell is set to three or more levels, and the level of a word line is changed to two or more levels to read out a memory cell, so that two bits or more of data can be stored in one memory cell. In a nonvolatile storage device configured to store, a binary data register (REG1, REG2), a data conversion logic circuit (11) for executing a predetermined operation on a plurality of bits of the input data and converting it to multi-valued data according to a combination thereof, An inverse conversion logic circuit (14) for converting the value data into the original binary data is provided. |