NONVOLATILE MEMORY CONTROL METHOD AND SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To return a threshold to a state before fluctuation without undesirably increasing writing frequencies in a nonvolatile memory. SOLUTION: A system includes: a nonvolatile memory (14); a random number generator (12); and a controller (11) capable of accessing the nonvolatile memory, and determines an area for refreshment with the controller based on random numbers generated by the random number generator whenever the nonvolatile memory is accessed. Then, the controller is made to execute refreshment control for performing rewrite to the area for refreshment. By such refreshment control, the threshold is returned to the state before fluctuation without undesirably increasing writing frequencies. COPYRIGHT: (C)2010,JPO&INPIT