4552 Datasheet, PDF (20/145 Pages) Renesas Technology Corp – SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

4552 Group
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 Z, X, and Y. Set a value to the
data pointer certainly when executing an instruction to access
RAM (also, set a value after system returns from power down
mode).
RAM includes the area for LCD.
When writing “1” to a bit corresponding to displayed segment, the
segment is turned on.
Table 2 shows the RAM size. Figure 12 shows the RAM map.
Table 2 RAM size
Part number
M34552M4/M4H
M34552M8/M8H
M34552G8/G8H
RAM size
288 words ✕ 4 bits (1152 bits)
• Note
Register Z of data pointer is undefined after system is released
from reset.
Also, registers Z, X and Y are undefined in the power down mode.
After system is returned from the power down mode, set these reg-
isters.
RAM 288 words ✕ 4 bits (1152 bits)
Register Z
0
1
Register X 0 ₁ 2 3 ^... 12 13 14 15 0 1 2 3
0
1
2
3
4
5
6
7
8
0 8 ^{16 24}
9
1 ^{9 17 25}
10
2 _{10 18 26}
11
3 11 19 ₂₇
12
4 12 _{20 28}
13
5 21
14
6 14 22
15
7 15 23
Note: The numbers in the shaded area indicate the corresponding segment output pin numbers.
Fig. 12 RAM map
Rev.3.02 Dec 22, 2006 page 20 of 142
REJ03B0023-0302