UPD78F0988AGC-8BS Renesas Electronics America, UPD78F0988AGC-8BS Datasheet - Page 286

• Manufacturer Part Number: UPD78F0988AGC-8BS
• Manufacturer: Renesas Electronics America

Specifications of UPD78F0988AGC-8BS

• Lead Free Status / Rohs Status: Supplier Unconfirmed

15.2 Registers Controlling External Device Expansion Function
284
The external device expansion function is controlled by the following three registers.
• Memory expansion mode register (MEM)
• Memory expansion wait setting register (MM)
• Memory size switching register (IMS)
(1) Memory expansion mode register (MEM)
MEM is a register that sets an external expansion area.
MEM is set by an 8-bit memory manipulation instruction.
RESET input clears this register to 00H.
Caution Always set bits 3 to 7 to 0.
Remark
Symbol
MEM
MEM2
Other than above
: don’t care
7
0
0
0
MEM1
Figure 15-2. Format of Memory Expansion Mode Register
6
0
0
1
CHAPTER 15 EXTERNAL DEVICE EXPANSION FUNCTION
MEM0
5
0
0
expansion mode selection
Single-chip mode
256-byte memory
expansion mode
Setting prohibited
4
0
Single-chip/memory
User’s Manual U13029EJ7V1UD
3
0
MEM2 MEM1 MEM0
2
1
Port mode
AD0 to AD7
P40 to P47, P64 to P67 pin status
P40 to P47
0
Address
FF47H
P64 = RD
P65 = WR
P66 = WAIT
P67 = ASTB
P64 to P67
After reset
00H
R/W
W