DATA REWRITING METHOD FOR NONVOLATILE MEMORY-MOUNTED MICROCONTROLLER

PROBLEM TO BE SOLVED: To prohibit a rewriting request when the number of rewriting times of a flash memory-mounted microcontroller exceeds an upper limit number of the rewriting times. SOLUTION: The microcontroller mounted with a central processing unit and a nonvolatile memory is provided with a rewriting number record area 102a inside the nonvolatile memory 102. When the nonvolatile memory 102 accepts the rewriting request, the number of the rewriting times recorded in the rewriting number record area 102a is read, and is compared to the upper limit number of the rewriting times. When it is less than the upper limit number of the rewriting times, a value obtained by adding one to the number of the rewriting times is recorded in the rewriting number record area 102a. When it is not less than the upper limit number of the rewriting times, the rewriting request is prohibited. COPYRIGHT: (C)2005,JPO&NCIPI