Method for reading multiple-value memory cells

A method for reading a plurality of bits stored in a selected multiple-value memory cell of a nonvolatile semiconductor memory device, the method comprising the following steps in this order:

• obtaining a first bit of the plurality of bits from the selected multiple-value memory cell by applying a first voltage to the control gate of the selected multiple-value memory cell;
• obtaining a first data from the selected multiple-value memory cell by applying a second voltage to the control gate of the selected multiple-value memory cell;
• obtaining a second data from the selected multiple-value memory cell by applying a third voltage to the control gate of the selected multiple-value memory cell;
• and
• obtaining a second bit of the plurality of bits stored in the selected multiple-value memory cell by performing a predetermined calculation on the first data and the second data.

A method for reading a plurality of bits stored in a selected multiple-value memory cell of a nonvolatile semiconductor memory device, the method comprising:

• obtaining a first data by applying a first voltage to a control gate of the selected multiple-value memory cell;
• obtaining a second data by applying a second voltage to the control gate of the selected multiple-value memory cell, the second voltage being higher than the first voltage;
• obtaining a first bit of the plurality of bits stored in the selected multiple-value memory cell by performing a predetermined calculation on the first data and the second data;
• and
• obtaining a second bit of the plurality of bits by applying a third voltage to the control gate of the selected multiple-value memory cell, the third voltage being lower than the second voltage and higher than the first voltage.