Holtek HT48R05A-1, Handbook, Page: 63 / 125

DAA [m] Decimal-Adjust ACC for addition with result in Data Memory
Description Convert the contents of the Accumulator value to a BCD ( Binary Coded Decimal) value re-
sulting from the previous addition of two BCD variables. If the low nibble is greater than 9 or
if AC flag is set, then a value of 6 will be added to the low nibble. Otherwise the low nibble
remains unchanged. If the high nibble is greater than 9 or if the C flag is set, then a value of
6 will be added to the high nibble. Essentially, the decimal conversion is performed by add-
ing 00H, 06H, 60H or 66H depending on the Accumulator and flag conditions. Only the C
flag may be affected by this instruction which indicates that if the original BCD sum is
greater than 100, it allows multiple precision decimal addition.
Operation
[m]
¬
ACC + 00H or
[m]
¬
ACC + 06H or
[m]
¬
ACC + 60H or
[m]
¬
ACC + 66H
Affected flag(s) C
DEC [m] Decrement Data Memory
Description Data in the specified Data Memory is decremented by 1.
Operation
[m]
¬
[m]
-
1
Affected flag(s) Z
DECA [m] Decrement Data Memory with result in ACC
Description Data in the specified Data Memory is decremented by 1. The result is stored in the Accu-
mulator. The contents of the Data Memory remain unchanged.
Operation
ACC
¬
[m]
-
1
Affected flag(s) Z
HALT Enter Power Down Mode
Description This instruction stops the program execution and turns off the system clock. The contents
of the Data Memory and registers are retained. The WDT and prescaler are cleared. The
Power Down flag PDF is set and the WDT time-out flag TO is cleared.
Operation
TO
¬
0
PDF
¬
1
Affected flag(s) TO, PDF
INC [m] Increment Data Memory
Description Data in the specified Data Memory is incremented by 1.
Operation
[m]
¬
[m]
+
1
Affected flag(s) Z
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Cost-Effective I/O Type MCU