15
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
3822 Group
MITSUBISHI MICROCOMPUTERS
MEMORY
Special Function Register (SFR) Area
The Special Function Register area in the zero page contains con-
trol registers such as I/O ports and timers.
RAM
RAM is used for data storage and for stack area of subroutine
calls and interrupts.
ROM
The first 128 bytes and the last 2 bytes of ROM are reserved for
device testing and the rest is user area for storing programs.
Interrupt Vector Area
The interrupt vector area contains reset and interrupt vectors.
Zero Page
The 256 bytes from addresses 0000
16
to 00FF
16
are called the
zero page area. The internal RAM and the special function regis-
ter (SFR) are allocated to this area.
The zero page addressing mode can be used to specify memory
and register addresses in the zero page area. Access to this area
with only 2 bytes is possible in the zero page addressing mode.
Special Page
The 256 bytes from addresses FF00
16
to FFFF
16
are called the
special page area. The special page addressing mode can be
used to specify memory addresses in the special page area.
Access to this area with only 2 bytes is possible in the special
page addressing mode.
Fig. 12 Memory map diagram
1
9
2
2
5
6
3
8
4
5
1
2
6
4
0
7
6
8
8
9
6
1
0
2
4
0
F
F
1
6
0
1
3
F
1
6
0
1
B
F
1
6
0
2
3
F
1
6
0
2
B
F
1
6
0
3
3
F
1
6
0
3
B
F
1
6
0
4
3
F
1
6
R
A
M
a
r
e
a
R
A
(
b
M
y
e
s
i
z
)
e
t
s
A
X
d
X
d
r
e
X
1
s
s
6
X
4
0
9
6
8
1
9
2
1
2
2
8
8
1
6
3
8
4
2
0
4
8
0
2
4
5
7
6
2
8
6
7
2
3
2
7
6
8
3
6
8
6
4
4
0
9
6
0
4
5
0
5
6
4
9
1
5
2
F000
16
E000
16
D000
16
C000
16
B000
16
A000
16
9000
16
8000
16
7000
16
6000
16
5000
16
4000
16
F080
16
E080
16
D080
16
C080
16
B080
16
A080
16
9080
16
8080
16
7080
16
6080
16
5080
16
4080
16
R
O
M
a
r
e
a
ROM size
(bytes)
A
Y
d
Y
d
Y
r
e
Y
1
s
s
6
A
Z
d
Z
d
Z
r
e
Z
1
s
s
6
0100
16
0
0
0
1
6
0
0
4
5
0
1
0
1
6
6
0
8
4
0
1
6
F
0
0
1
6
FFDC
16
FFFE
16
F
F
F
1
6
X
X
X
1
6
Y
Y
Y
1
6
ZZZZ
16
RAM
ROM
Reserved area
SFR area
Not used
I
n
t
e
r
r
u
p
t
v
e
c
t
o
r
a
r
e
a
Reserved ROM area
(128 bytes)
Zero page
Special page
Reserved ROM area
L
C
D
d
i
s
p
l
a
y
R
A
M
a
r
e
a