Since the value of the processor mode control register (PMC) cannot be changed in the RL78-S1 core, this setting is not required. As the PMC value becomes 0 at a reset in the RL78-S2 core or RL78-S3 core, this setting should be made only when the MAA bit value of PMC is to be changed.
For details on the mirror area, PMC, and MAA, see the user's manual of the device.