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Rev. 1.20
44
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Rev. 1.20
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HT69F30A/HT69F40A/HT69F50A
TinyPower
TM
I/O Flash 8-Bit MCU with LCD & EEPROM
HT69F30A/HT69F40A/HT69F50A
TinyPower
TM
I/O Flash 8-Bit MCU with LCD & EEPROM
Bank Pointer – BP
Depending upon which device is used, the Data Memory is divided into several banks. Selecting
the required Data Memory area is achieved using the Bank Pointer. Bits 0~1 of the Bank Pointer are
used to select Data Memory Banks 0~3.
The Data Memory is initialised to Bank 0 after a reset, except for a WDT time-out reset in the Power
Down Mode, in which case, the Data Memory bank remains unaffected. It should be noted that the
Special Function Data Memory is not affected by the bank selection, which means that the Special
Function Registers can be accessed from within any bank. Directly addressing the Data Memory
will always result in Bank 0 being accessed irrespective of the value of the Bank Pointer. Accessing
data from banks other than Bank 0 must be implemented using Indirect addressing.
As both the Program Memory and Data Memory share the same Bank Pointer Register, care must be
taken during programming.
Device
Bit
7
6
5
4
3
2
1
0
HT69F30A
—
—
—
—
—
—
—
DMBP0
HT69F40A
—
—
—
—
—
—
DMBP1
DMBP0
HT69F�0A
—
—
—
—
—
—
DMBP1
DMBP0
BP Register List
BP Register
•
HT69F30A
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
—
DMBP0
R/W
—
—
—
—
—
—
—
R/W
P�R
—
—
—
—
—
—
—
0
Bit 7~1
Unimplemented, read as "0"
Bit 0
DMBP0:
Data memory bank point
0: Bank 0
1: Bank 1
•
HT69F40A
Bit
7
6
5
4
3
2
1
0
Name
—
—
—
—
—
—
DMBP1
DMBP0
R/W
—
—
—
—
—
—
R/W
R/W
P�R
—
—
—
—
—
—
0
0
Bit 7~2
Unimplemented, read as "0"
Bit 1~0
DMBP1, DMBP0:
Data memory bank point
00: Bank 0
01: Bank 1
10: Bank 2
11: Undefined