Patent ID: 8291188

Claim:
A microcontroller comprising a plurality of CPUs and a memory map register and carrying out control of an external device based on an instruction processing from the CPUs in accordance with data written to the memory map register, wherein the memory map register has a register storing information about the number of writes of write data, instruction processing about specific processing set in advance in the instruction processing from the CPUs is executed twice for the memory map register, the two writes of the write data to the memory map register executed by the same instruction processing, each from different ones of the CPUs, and a write data comparison circuit mutually collating the write data written twice to the memory map register is provided, in each of the two write writes of the write data to the memory map register based on the same instruction processings from the different ones of the CPUs, write processing is executed only when a collation result in the write data comparison circuit is a match.