upd6p9 Renesas Electronics Corporation., upd6p9 Datasheet - Page 13

• Manufacturer Part Number: upd6p9
• Description: 4-bit Single-chip Microcontroller For Infrared Remote Control Transmission
• Manufacturer: Renesas Electronics Corporation.

3.5 Data Memory (RAM): 128 × 4 Bits
The data memory is sometimes processed in 8-bit units. R0 of page 0 can be used as the ROM data pointer.
(undefined when turning on the power).
The data memory, which is a static RAM consisting of 32 × 4 bits × 4 pages, is used to retain processed data.
RF of page 0 is also used as the ASR.
After reset, R0 of page 0 is cleared to 00H and R1 to RF of page 0 and pages 1 to 3 retain the previous data
Notes 1. Pages 0 to 3 can be switched using bits 0 and 1 of control register 0.
2. R0 of page 0 alternately functions as the ROM data pointer (refer to 3.6 Data Pointer (DP)).
3. RF of page 0 alternately functions as the PC address stack (refer to 3.3 Address Stack Register
(ASR (RF)).
Figure 3-4. Data Memory Configuration
R
1n
(higher 4 bits) R
Data Sheet U15144EJ1V1DS
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
Pages 0 to 3
10
11
12
13
14
15
16
17
18
19
1A
1B
1C
1D
1E
1F
RC
RD
R0
R1
R2
R3
R4
R5
R6
R7
R8
R9
RA
RB
RE
RF
0n
Note 1
(lower 4 bits)
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
R
0A
0B
0C
0D
0E
0F
00
01
02
03
04
05
06
07
08
09
→Note 2
→Note 3
µ PD6P9
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