
CHAPTER 3 CPU FUNCTION
User’s Manual U15905EJ2V1UD
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(3) Internal peripheral I/O area
4 KB of addresses 3FFF000H to 3FFFFFFH are allocated as the internal peripheral I/O area.
Figure 3-9. Internal Peripheral I/O Area
Internal peripheral I/O area
(4 KB)
3FFFFFFH
3FFF000H
Peripheral I/O registers that have functions to specify the operation mode for and monitor the status of the
internal peripheral I/O are mapped to the internal peripheral I/O area. Program cannot be fetched from this
area.
Cautions 1. When a register is accessed in word units, a word area is accessed twice in halfword
units in the order of lower area and higher area, with the lower 2 bits of the address
ignored.
2. If a register that can be accessed in byte units is accessed in halfword units, the higher 8
bits are undefined when the register is read, and data is written to the lower 8 bits.
3. Addresses not defined as registers are reserved for future expansion. The operation is
undefined and not guaranteed when these addresses are accessed.
(4) External memory area
15 MB (0100000H to 0FFFFFFH) are allocated as the external memory area. For details, refer to CHAPTER 5
BUS CONTROL FUNCTION.