![NEC V850/SC1 Скачать руководство пользователя страница 106](http://html.mh-extra.com/html/nec/v850-sc1/v850-sc1_user-manual_248178106.webp)
CHAPTER 3 CPU FUNCTIONS
User’s Manual U15109EJ3V0UD
104
(1) Memory expansion mode register (MM)
This register sets the mode of each pin of ports 4, 5, 6, and 9 in the V850/SC1, V850/SC2, and V850/SC3. In the
external expansion mode, an external device can be connected to an external memory area of up to 4 MB.
However, the external device cannot be connected to the internal RAM area, on-chip peripheral I/O area, and
internal ROM area in the single-chip mode (and even if the external device is connected physically, it cannot be
accessed).
The MM register can be read/written in 8- or 1-bit units. However, bits 4 to 7 are fixed to 0.
After reset: 00H
R/W
Address: FFFFF04CH
Symbol
7
6
5
4
<3>
<2>
<1>
<0>
MM
0
0
0
0
MM3
MM2
MM1
MM0
MM3
P95 and P96 operating modes
0
Port mode
1
External expansion mode (HLDAK: P95, HLDRQ: P96)
MM2
MM1
MM0
Address space
Port 4
Port 5
Port 6
Port 9
0
0
0
−
Port mode
0
1
1
64 KB
expansion mode
1
0
0
256 KB
expansion mode
1
0
1
1 MB
expansion mode
1
1
×
4 MB
expansion mode
AD0 to AD7
AD8 to AD15
A16,
A17
A18,
A19
A20,
A21
LBEN,
UBEN,
R/W, DSTB,
ASTB,
WRL
Note
,
WRH
Note
,
RD
Note
Other than above
RFU (reserved)
Note
Only for the V850/SC1 and V850/SC2
Caution Before switching to the external expansion mode, be sure to set P93 and P94 of port 9 (P9)
to 1.
Remark
For details of the operation of each port pin, refer to
2.3 Description of Pin Functions
.