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NEC uPD78053Y User Manual

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CHAPTER 22   EXTERNAL DEVICE EXPANSION FUNCTION
7
0
Symbol
MM
6
0
5
PW1
4
PW0
3
0
2
MM2
1
MM1
0
MM0
Address
FFF8H
10H
When
Reset
R/W
R/W
MM2
MM1
MM0
Single-chip/
Memory Expansion
Mode Selection
P40-P47, P50-P57, P64-P67 Pin state 
P40-P47
P50-P53
P54, P55
P56, P57
P64-P67
0
0
0
0
0
1
0
1
1
1
0
0
1
0
1
1
1
1
Single-chip mode
256-byte
mode
4K-byte
mode
16K-byte
mode
Full 
address
mode
Note
Memory
expansion
mode
Port
mode
Input
Output
Port mode
Port mode
Port mode
Port mode
AD0-AD7
A8-A11
A12, A13
A14, A15
P64=RD
P65=WR
P66=WAIT
P67=ASTB
Other than above
Setting prohibited
PW1
PW0
0
0
0
1
1
0
1
1
Wait Control
No wait
Wait (one wait state insertion)
Setting prohibited
Wait control by external wait pin
22.2   External Device Expansion Function Control Register
The external device expansion function is controlled by the memory expansion mode register (MM) and memory
size switching register (IMS).
(1) Memory expansion mode register (MM)
MM sets the wait count and external expansion area, and also sets the input/output of port 4.
MM is set with an 1-bit memory or 8-bit memory manipulation instruction.
RESET input sets this register to 10H.
Figure 22-2.  Memory Expansion Mode Register Format
Note
The full address mode allows external expansion to the entire 64-Kbyte address space except for
the internal ROM, RAM, and SFR areas and the reserved areas.
Remark
P60 to P63 enter the port mode without regard to the mode (single-chip mode or memory expansion
mode).