MITSUBISHI MICROCOMPUTERS
38B5 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
8
PRELIMINARY
Notice: This s not a final specification.
Some parametric imits are subject to change.
Memory
Special function register (SFR) area
The special function register (SFR) area in the zero page contains
control 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 other areas are user areas for storing pro-
grams.
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 registers (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 spe-
cial 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. 6 Memory Map Diagram
0100
16
0000
16
0040
16
0440
16
FF00
16
FFDC
16
FFFE
16
FFFF
16
192
256
384
512
640
768
896
1024
1536
2048
XXXX
16
00FF
16
013F
16
01BF
16
023F
16
02BF
16
033F
16
03BF
16
043F
16
063F
16
083F
16
4096
8192
12288
16384
20480
24576
28672
32768
36864
40960
45056
49152
53248
57344
61440
F000
16
E000
16
D000
16
C000
16
B000
16
A000
16
9000
16
8000
16
7000
16
6000
16
5000
16
4000
16
3000
16
2000
16
1000
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
3080
16
2080
16
1080
16
YYYY
16
ZZZZ
16
RAM
ROM
0EF0
16
0EFF
16
0F00
16
0FFF
16
Reserved area
SFR area 1
Not used (Note)
Interrupt vector area
ROM area
Reserved ROM area
(common ROM area,128 byte)
Zero page
Special page
RAM area
RAM size
(byte)
Address
XXXX
16
ROM size
(byte)
Address
YYYY
16
Reserved ROM area
Address
ZZZZ
16
SFR area 2
RAM area for Serial I/O automatic
transfer
Note
: When 1024 bytes or more are used as RAM area, this area can be used.