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CHAPTER 3 CPU
3.8 Memory Access Mode
The MB89202/F202RA series supports only single-chip mode for access to memory.
■ Single-chip Mode
In single-chip mode, only internal RAM and ROM are used. The CPU can access only the internal I/O area,
RAM area, and ROM area.
■
Mode Data
Set 00
H
into the mode data in internal ROM to select single-chip mode.
Figure 3.8-1 Configuration of Mode Data
■
Operations for Selecting Memory Access Mode
Only single-chip mode is selectable.
Table 3.8-1 provides the settings for the mode pins and mode data.
Figure 3.8-2 shows the operations for selecting memory access.
00
H
bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
FFFD
H
Address
Value
Operation
Selects single-chip mode.
Other than 00
H
Reserved. Do not specify this value.
Table 3.8-1 Settings for Mode Data
Memory access mode Mode data
Single-chip mode 00
H
Other modes Prohibited