HT46R01B/02B/01N/02N
HT48R01B/02B/01N/02N
Data Memory
The Data Memory is a volatile area of 8-bit wide RAM
internal memory and is the location where temporary in-
formation is stored.
Special Purpose Data Memory
This area of Data Memory is where registers, necessary
for the correct operation of the microcontroller, are
stored. Most of the registers are both readable and
writeable but some are protected and are readable only,
the details of which are located under the relevant Spe-
cial Function Register section. Note that for locations
that are unused, any read instruction to these addresses
will return the value ²00H².
Structure
Divided into two sections, the first of these is an area of
RAM where special function registers are located. These
registers have fixed locations and are necessary for cor-
rect operation of the device. Many of these registers can
be read from and written to directly under program con-
trol, however, some remain protected from user manipu-
lation. The second area of Data Memory is reserved for
general purpose use. All locations within this area are
read and write accessible under program control.
H
T
4
6
R
0
H
1
T
B
4
4
6
6
R
0
H
2
B
T
T
4
4
8
8
R
0
H
1
T
T
B
4
4
8
8
H
T
4
6
R
0
H
1
T
N
R
0
H
2
N
R
0
H
1
N
I
I
A
A
R
R
0
1
I
I
A
A
R
R
0
1
I
A
R
0
I
I
A
A
R
R
0
0
0
0
0
0
0
0
0
0
0
1
2
3
4
5
6
7
8
9
H
H
H
H
H
H
H
H
H
H
H
H
M
M
P
P
0
1
M
M
P
P
0
1
M
P
0
M
M
P
P
0
1
I
A
R
1
M
P
1
The two sections of Data Memory, the Special Purpose
and General Purpose Data Memory are located at con-
secutive locations. All are implemented in RAM and are 8
bits wide but the length of each memory section is dic-
tated by the type of microcontroller chosen. The start ad-
dress of the Data Memory for all devices is the address
²00H².
A
C
C
A
C
C
A
C
C
A
C
C
P
C
L
P
C
L
P
C
L
P
C
L
T
B
L
P
T
B
L
P
T
B
L
P
T
B
L
T
B
L
H
T
B
L
H
T
B
L
H
T
B
L
W
D
T
S
W
D
T
S
W
D
T
S
W
D
T
S
T
A
T
U
S
S
T
A
T
U
S
S
T
A
T
U
S
S
T
A
T
0
0
A
B
I
N
T
C
0
I
N
T
C
0
I
N
T
C
0
I
N
T
C
T
T
M
M
R
R
0
1
T
T
M
M
R
R
0
1
T
T
M
M
R
R
0
1
T
T
M
M
R
R
0
0
C
D
H
T
T
M
M
R
R
0
1
C
C
T
T
M
M
R
R
0
1
C
C
T
T
M
M
R
R
0
1
C
C
T
T
M
M
R
R
0
1
H
0
E
H
H
H
H
H
H
H
H
H
H
H
H
H
H
0
F
All microcontroller programs require an area of
read/write memory where temporary data can be stored
and retrieved for use later. It is this area of RAM memory
that is known as General Purpose Data Memory. This
area of Data Memory is fully accessible by the user pro-
gram for both read and write operations. By using the
²SET [m].i² and ²CLR [m].i² instructions individual bits
can be set or reset under program control giving the
user a large range of flexibility for bit manipulation in the
Data Memory.
P
A
P
A
P
A
P
A
1
1
1
1
1
1
1
1
1
1
0
1
2
3
4
5
6
7
8
9
P
A
C
P
A
C
P
A
C
P
A
C
P
A
P
U
P
A
P
U
P
A
P
U
P
A
P
P
A
W
K
P
A
W
K
P
A
W
K
P
A
W
P
B
P
B
P
B
P
B
P
B
C
P
B
C
P
B
C
P
B
C
P
B
P
U
P
B
P
U
P
B
P
U
P
B
P
C
T
R
L
0
C
T
R
L
0
C
T
R
L
0
C
T
R
L
1
1
A
B
C
T
R
L
1
C
T
R
L
1
C
T
R
L
1
C
T
R
L
1
1
C
D
H
H
I
N
T
C
1
I
N
T
C
1
I
N
T
C
1
I
N
T
C
1
E
H
H
H
P
W
M
0
P
W
0
M
1
F
0
0
0
1
H
H
I
A
R
0
A
D
R
L
A
D
R
L
2
0
A
D
R
C
H
A
D
R
C
H
2
1
H
H
H
H
H
S
P
R
p
u
e
r
c
i
a
l
M
P
0
A
D
R
A
D
R
2
2
2
2
2
3
4
5
p
o
s
e
A
C
S
R
A
C
S
R
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g
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s
t
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r
s
3
F
H
H
4
0
9
6
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9
F
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Special Purpose Data Memory
Data Memory Structure
Note: Most of the Data Memory bits can be directly
manipulated using the ²SET [m].i² and ²CLR
[m].i² with the exception of a few dedicated bits.
The Data Memory can also be accessed
through the memory pointer registers.
Rev.1.10
15
February 12, 2010
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
