HT48R03 Holtek Semiconductor, HT48R03 Datasheet - Page 9

• Manufacturer Part Number: HT48R03
• Description: (HT48R01 - HT48R03) 10-Pin MSOP I/O Type 8-Bit OTP MCU
• Manufacturer: Holtek Semiconductor

Status Register - STATUS
This 8-bit register (0AH) contains the zero flag (Z), carry
flag (C), auxiliary carry flag (AC), overflow flag (OV),
power down flag (PDF), and watchdog time-out flag
(TO). It also records the status information and controls
the operation sequence.
With the exception of the TO and PDF flags, bits in the
status register can be altered by instructions like most
other registers. Any data written into the status register
Rev. 1.00
Bit No.
6~7
0
1
2
3
4
5
Label
C
AC
Z
OV
PDF
TO
C is set if the operation results in a carry during an addition operation or if a borrow does not
take place during a subtraction operation; otherwise C is cleared. C is also affected by a rotate
through carry instruction.
AC is set if the operation results in a carry out of the low nibbles in addition or no borrow from
the high nibble into the low nibble in subtraction; otherwise AC is cleared.
Z is set if the result of an arithmetic or logic operation is zero; otherwise Z is cleared.
OV is set if the operation results in a carry into the highest-order bit but not a carry out of the
highest-order bit, or vice versa; otherwise OV is cleared.
PDF is cleared by system power-up or executing the CLR WDT instruction.
PDF is set by executing the HALT instruction.
TO is cleared by system power-up or executing the CLR WDT or HALT instruction.
TO is set by a WDT time-out.
Unused bit, read as 0
Status (0AH) Register
RAM Mapping
9
will not change the TO or PDF flag. In addition opera-
tions related to the status register may give different re-
sults from those intended. The TO flag can be affected
only by system power-up, a WDT time-out or executing
the CLR WDT or HALT instruction. The PDF flag
can be affected only by executing the HALT or CLR
WDT instruction or a system power-up.
The Z, OV, AC and C flags generally reflect the status of
the latest operations.
Function
HT48R01/HT48R02/HT48R03
December 20, 2006