MITSUBISHI MICROCOMPUTERS
4280 Group
SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER for INFRARED REMOTE CONTROL TRANSMITTERS
PROGRAM MEMORY (ROM)
8
7
6
5 4 3 2 1 0
The program memory is a mask ROM. 1 word of ROM is
composed of 9 bits. ROM is separated every 128 words by the
unit of page (addresses 0 to 127).
000016
007F16
008016
Page 0
Page 1
Page 2
Page 3
00FF16
010016
017F16
018016
Table 1 ROM size and pages
Subroutine special page
Product
ROM size (✕ 9 bits)
Pages
M34280M1
M34280E1
1024 words
8 (0 to 7)
Page 2 (addresses 010016 to 017F16) is the special page for
subroutine calls. Subroutines written in this page can be called
from any page with the 1-word instruction (BM). Subroutines
extending from page 2 to another page can also be called with
the BM instruction when it starts on page 2.
03FF16
Page 7
Fig. 10 ROM map of M34280M1
ROM pattern of all addresses can be used as data areas with
the TABP p instruction.
DATA MEMORY (RAM)
1 word of RAM is composed of 4 bits, but 1-bit manipulation
(with the SB j, RB j, and SZB j instructions) is enabled for the
entire memory area. A RAM address is specified by a data
pointer. The data pointer consists of registers X and Y. Set a
value to the data pointer certainly when executing an instruction
to access RAM.
RAM 32 words × 4 bits (128 bits)
Register X
0
2 3
1
0
1
2
3
Table 2 shows the RAM size. Figure 12 shows the RAM map.
4
5
6
7
Table 2 RAM size
Product
RAM size
M34280M1
M34280E1
32 words ✕ 4 bits (128 bits)
32 words
Fig. 11 RAM map
MITSUBISHI
ELECTRIC
9
MITSUBISHI [ Mitsubishi Group ]
