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CHAPTER 3 CPU
3.1 Memory Space
The MB89202/F202RA series has 64-KB memory space that consists of the I/O area,
RAM area, ROM area, and external area. Part of the memory space is applied for specific
use such as general-purpose registers or a vector table.
■ Configuration of Memory Space
● I/O area (address: 0000
H
to 007F
H
)
The control registers and data registers for built-in peripheral functions are assigned.
The I/O area is assigned as part of the memory space, thus access to the I/O area can be obtained in the
same manner as access to memory. Also, direct addressing provides high-speed access.
● RAM area
Static RAM is equipped as the internal data area.
The size of internal RAM depends on the model.
Direct addressing allows high-speed access to an area from 80
H
to FF
H
. (Some models restrict the usable
range of the area.)
100
H
to 1FF
H
can be used as the general-purpose register area.
If a reset occurs while data is being written into RAM, the data being written cannot be guaranteed.
● ROM area
ROM is equipped as the internal program area.
The size of internal ROM depends on the model.
FFC0
H
to FFFF
H
are usable as a vector table or another feature.