PIC16F505 Microchip Technology, PIC16F505 Datasheet - Page 22

• Manufacturer Part Number: PIC16F505
• Description: (PIC1xF50x) 8-Bit Flash Microcontrollers
• Manufacturer: Microchip Technology

PIC12F508/509/16F505
4.4
This register contains the arithmetic status of the ALU,
the Reset status and the page preselect bit.
The Status register can be the destination for any
instruction, as with 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 4-1:
DS41236A-page 20
Status Register
bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
STATUS REGISTER (ADDRESS: 03h) (PIC12F508/509)
GPWUF: GPIO Reset bit
1 = Reset due to wake-up from Sleep on pin change
0 = After power-up or other Reset
Reserved: Do not use
PA0: Program Page Preselect bits
1 = Page 1 (200h-3FFh)
0 = Page 0 (000h-1FFh)
Each page is 512 bytes.
Using the PA0 bit as a general purpose read/write bit in devices which do not use it for program page
preselect is not recommended, since this may affect upward compatibility with future products.
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/borrow bit (for ADDWF and SUBWF instructions)
ADDWF:
1 = A carry from the 4th low-order bit of the result occurred
0 = A carry from the 4th low-order bit of the result did not occur
SUBWF:
1 = A borrow from the 4th low-order bit of the result did not occur
0 = A borrow from the 4th low-order bit of the result occurred
C: Carry/borrow bit (for ADDWF, SUBWF and RRF, RLF instructions)
ADDWF:
1 = A carry occurred
0 = A carry did not occur
bit 7
Legend:
R = Readable bit
-n = Value at POR
GPWUF
Note 1: This bit is used on the PIC12F509. For code compatibility do not use this bit on the
R/W-0
PIC12F508.
R/W-0
—
R/W-0
PA0
Preliminary
SUBWF:
1 = A borrow did not occur
0 = A borrow occurred
W = Writable bit
‘1’ = Bit is set
(1)
R-1
TO
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).
Therefore, it is recommended that only BCF, BSF and
MOVWF instructions be used to alter the Status register.
These instructions do not affect the Z, DC or C bits from
the Status register. For other instructions which do
affect Status bits, see Section 8.0 “Instruction Set
Summary”.
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
R-1
PD
RRF or RLF:
Load bit with LSb or MSb, respectively
R/W-x
 2004 Microchip Technology Inc.
Z
x = Bit is unknown
R/W-x
DC
R/W-x
C
bit 0