3820_03 Datasheet, PDF (29/349 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS
3820 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
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 000016 to 00FF16 are called the
zero page area. The internal RAM and the special function regis-
ters (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 FF0016 to FFFF16 are called the
special page area. The special page addressing mode can be
used to specify memory addresses in the special page area. Ac-
cess to this area with only 2 bytes is possible in the special page
addressing mode.
RAM area
RAM size
(bytes)
192
256
384
512
640
768
896
1024
Address
XXXX16
00FF16
013F16
01BF16
023F16
02BF16
033F16
03BF16
043F16
ROM area
ROM size
(bytes)
4096
8192
12288
16384
20480
24576
28672
32768
Address
YYYY16
F00016
E00016
D00016
C00016
B00016
A00016
900016
800016
Address
ZZZZ16
F08016
E08016
D08016
C08016
B08016
A08016
908016
808016
Fig. 9 Memory map diagram
RAM
000016
SFR area
004016 _{LCD display RAM area}
005416
010016
Zero page
XXXX16
Reserved area
044016
Not used
YYYY16
Reserved ROM area
(128 bytes)
ZZZZ16
ROM
FF0016
FFDC16
Interrupt vector area
FFFE16 _{Reserved ROM area}
FFFF16
Special page
1-12
3820 GROUP USER’S MANUAL