If the sum value of the object file does not match the sum value at the time of writing, the following factors may be the cause:
① The method of calculating the sum value of the object file and the method of calculating the sum value of the writer are different.
The programmer's sum value calculation uses a simple addition method that ignores overflow. If the object file's sum value calculation uses complement calculation, it will not match the programmer's sum value, so please check the object file's sum value calculation method.
② The data size of the object file is smaller than the size of the flash memory.
The programmer calculates the sum value for the range that was actually programmed to the flash memory. Normally, the sum value is calculated assuming that there is FF data in the parts of the object file where there is no data. (If buffer clearing is performed before file loading)
③ Buffer clearing is not performed before file loading.
If buffer clearing is not performed, some of the previously loaded content may remain in the buffer memory, which may cause the sum value to not match.