Checksum writing method and checksum checking apparatus

摘要

A more convenient checksum writing method and checksum checking apparatus. The method includes: calculating a first checksum by reading values from the memory and summing the read values; calculating a first mode checksum by subtracting values written in a predetermined area of the memory from the first checksum; initializing a second checksum to be zero if the first mode checksum does not meet a predetermined condition; calculating a second mode checksum by inverting the second checksum and adding the inverted second checksum to the first mode checksum; and writing the inverted second checksum value in the predetermined area of the memory, if the second mode checksum is equal to the second checksum.