| 摘要 |
PROBLEM TO BE SOLVED: To realize a non-volatile semiconductor memory in which layout is easy to perform, a layout area can be reduced and discrimination for finish of writing can be performed for each step. SOLUTION: This device is a non-volatile semiconductor memory in which multi-values data of ternary or more is written in a memory cell with a page unit, in a NAND flash of multi-values (four values), writing/reading control circuits 12a, 12b has the same configuration as conventional circuit configuration of binary (0 and 1), instead of it, a page buffer 15 is provided. Conversion of (n) bits to 2<n> is performed by priority decoders 16a, 16b in writing, writing is performed one value by one value, in reading, inversely, reading is performed one value by one value by changing word line voltage, the read out result is stored in the page buffer 15 through adding circuits (conversion for 2<n> to (n) bits) 17a, 17b. |
