13-1 ROM and RAM Access (Required)
Description
Access to ROM and RAM must be restricted to areas that are originally mapped (physical addresses 0x10000000, to ROM capacity and 0x08000000 to RAM capacity).
ReasonIf an area other than those mentioned above is read, the value received is not constant. Sometimes the image of the ROM will be received, but this is not always the case with mass-produced boards.
Reference