
CHAPTER 20 EXTERNAL DEVICE EXPANSION FUNCTION
419
User
’
s Manual U14260EJ3V1UD
Note
When the CPU accesses the external memory expansion area, the lower bits of the address to be accessed
are output to the specified pins (except in the full-address mode).
Figure 20-3. Pins Specified for Address (with
μ
PD780076 and 780076Y)
External Expansion Mode
Address Accessed
by CPU
Pins Specified for Address
A15 A14 A13 A12 A11 A10 A9
A8 AD7 AD6 AD5 AD4 AD3 AD2 AD1 AD0
256-byte expansion mode
C000H
(1)
(1)
(0)
(0)
(0)
(0)
(0)
(0)
0
0
0
0
0
0
0
0
C001H
(1)
(1)
(0)
(0)
(0)
(0)
(0)
(0)
0
0
0
0
0
0
0
1
C055H
(1)
(1)
(0)
(0)
(0)
(0)
(0)
(0)
0
1
0
1
0
1
0
1
C0FEH
(1)
(1)
(0)
(0)
(0)
(0)
(0)
(0)
1
1
1
1
1
1
1
0
C0FFH
(1)
(1)
(0)
(0)
(0)
(0)
(0)
(0)
1
1
1
1
1
1
1
1
4 KB expansion mode
C000H
(1)
(1)
(0)
(0)
0
0
0
0
0
0
0
0
0
0
0
0
C001H
(1)
(1)
(0)
(0)
0
0
0
0
0
0
0
0
0
0
0
1
C100H
(1)
(1)
(0)
(0)
0
0
0
1
0
0
0
0
0
0
0
0
CFFFH
(1)
(1)
(0)
(0)
1
1
1
1
1
1
1
1
1
1
1
1
16 KB expansion mode
C000H
(1)
(1)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D000H
(1)
(1)
0
1
0
0
0
0
0
0
0
0
0
0
0
0
E000H
(1)
(1)
1
0
0
0
0
0
0
0
0
0
0
0
0
0
F000H
(1)
(1)
1
1
0
0
0
0
0
0
0
0
0
0
0
0
F3FFH
(1)
(1)
1
1
0
0
1
1
1
1
1
1
1
1
1
1
Full-address mode
C000H
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
C001H
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
1
F3FFH
1
1
1
1
0
0
1
1
1
1
1
1
1
1
1
1
Remark
The value in ( ) is not actually output. This pin can be used as a port pin.
(2) Memory expansion wait setting register (MM)
MM sets the number of waits.
MM is set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets MM to 10H.
Figure 20-4. Format of Memory Expansion Wait Setting Register (MM)
Address: FFF8H After reset: 10H R/W
Symbol
7
6
5
4
3
2
1
0
MM
0
0
PW1
PW0
0
0
0
0
PW1
PW0
Wait control
0
0
No wait
0
1
Wait (one wait state inserted)
1
0
Setting prohibited
1
1
Wait control by external wait pin
Cautions 1.
To control wait by the external wait pin, be sure to set the WAIT/P66 pin to input
mode (set bit 6 (PM66) of port mode register 6 (PM6) to 1).
When wait is not controlled by the external wait pin, the WAIT/P66 pin can be
used as an I/O port pin.
2.