PIC12F1840 MICROCHIP [Microchip Technology], PIC12F1840 Datasheet - Page 18

• Manufacturer Part Number: PIC12F1840
• Description: 8-Pin Flash Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

PIC12F/LF1840
3.2.1.1
The STATUS register, shown in
• the arithmetic status of the ALU
• the Reset status
The STATUS register can be the destination for any
instruction, like any other register. If the STATUS
register is the destination for an instruction that affects
the Z, DC or C bits, then the write to these three bits is
disabled. These bits are set or cleared according to the
device logic. Furthermore, the TO and PD bits are not
writable. Therefore, the result of an instruction with the
STATUS register as destination may be different than
intended.
REGISTER 3-1:
DS41441A-page 18
bit 7
Legend:
R = Readable bit
u = Bit is unchanged
‘1’ = Bit is set
bit 7-5
bit 4
bit 3
bit 2
bit 1
bit 0
Note 1:
U-0
—
For Borrow, the polarity is reversed. A subtraction is executed by adding the two’s complement of the
second operand.
STATUS Register
Unimplemented: Read as ‘0’
TO: Time-out bit
1 = After power-up, CLRWDT instruction or SLEEP instruction
0 = A WDT time-out occurred
PD: Power-down bit
1 = After power-up or by the CLRWDT instruction
0 = By execution of the SLEEP instruction
Z: Zero bit
1 = The result of an arithmetic or logic operation is zero
0 = The result of an arithmetic or logic operation is not zero
DC: Digit Carry/Digit Borrow bit
1 = A carry-out from the 4th low-order bit of the result occurred
0 = No carry-out from the 4th low-order bit of the result
C: Carry/Borrow bit
1 = A carry-out from the Most Significant bit of the result occurred
0 = No carry-out from the Most Significant bit of the result occurred
U-0
—
STATUS: STATUS REGISTER
W = Writable bit
x = Bit is unknown
‘0’ = Bit is cleared
Register
(1)
U-0
—
3-1, contains:
(1)
R-1/q
TO
Preliminary
U = Unimplemented bit, read as ‘0’
-n/n = Value at POR and BOR/Value at all other Resets
q = Value depends on condition
R-1/q
For example, CLRF STATUS will clear the upper three
bits and set the Z bit. This leaves the STATUS register
as ‘000u u1uu’ (where u = unchanged).
It is recommended, therefore, that only BCF, BSF,
SWAPF and MOVWF instructions are used to alter the
STATUS register, because these instructions do not
affect any Status bits. For other instructions not
affecting any Status bits (Refer to
“Instruction Set
PD
Note 1: The C and DC bits operate as Borrow
and Digit Borrow out bits, respectively, in
subtraction.
R/W-0/u
Z
Summary”).
 2011 Microchip Technology Inc.
R/W-0/u
DC
(1)
Section 29.0
R/W-0/u
C
(1)
bit 0