HT47C20 Holtek Semiconductor Inc, HT47C20 Datasheet - Page 12

• Manufacturer Part Number: HT47C20
• Description: 8-Bit Microcontroller
• Manufacturer: Holtek Semiconductor Inc

HT47C20
converter control register (ADCR; 25H). The re-
maining space before the 40H are reserved for fu-
ture expanded usage and reading these location
will return the result 00H. The general purpose
data memory, addressed from 40H to 7FH, is
used for data and control information under in-
struction command.
All data memory areas can handle arithme-
tic, logic, increment, decrement and rotate
operations. Except for some dedicated bits,
each bit in the data memory can be set and re-
set by the SET [m].i and CLR [m].i instruc-
tion, respectively. They are also indirectly
accessible through memory pointer registers
(MP0;01H, MP1;03H).
Indirect addressing register
Location 00H and 02H are indirect addressing
registers that are not physically implemented.
Any read/write operation of [00H] and [02H] ac-
cess data memory pointed to by MP0 (01H) and
MP1 (03H) respectively. Reading location 00H
or 02H indirectly will return the result 00H.
Writing indirectly results in no operation.
The function of data movement between two in-
direct addressing registers are not supported.
The memory pointer registers, MP0 and MP1,
are both 8-bit registers which can be used to ac-
cess the data memory by combining correspond-
ing indirect addressing registers.
Only MP0 can be applied to data memory, while
MP1 can be applied to data memory and LCD
display memory.
Accumulator
The accumulator is closely related to ALU op-
erations. It is also mapped to location 05H of
the data memory and is capable of carrying out
immediate data operations. The data move-
ment between two data memory locations
must pass through the accumulator.
RAM mapping (bank 0)
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January 18, 2000