Patent ID: 8391067

Claim:
A nonvolatile memory, comprising: a memory cell array including a plurality of memory cells, each of the memory cells capable of storing electric charges nonvolatilly; a first sense amplifier for comparing a voltage produced by one of the selected memory cells to be read out with a first threshold value for distinguishing between a write state and an erase state of the selected memory cell; a second sense amplifier for comparing the voltage produced by one of the selected memory cell with a second threshold value having a greater voltage than the first threshold voltage; and a write unit for rewriting data of the selected memory cell when the first and the second sense amplifiers produce different sense outputs from each other, wherein the nonvolatile memory includes a position for storing instructions, the nonvolatile memory reduces a first time interval to a second time interval if a plurality of access times exceed a threshold for determining a number of accesses to the memory cell, the first interval being a time for the voltage to be produced by one of the selected memory cell, with the second threshold value having the greater voltage than the first threshold voltage, and the second interval is the next time interval after the first interval being a time for the voltage to be produced by one of the selected memory cell with the second threshold value having the greater voltage than the first threshold voltage.