Datasheet

© 2007 Microchip Technology Inc. DS41206B-page 11
PIC16F716
2.2.2.1 STATUS Register
The STATUS register, shown in Register 2-1, contains
the arithmetic status of the ALU, the Reset status and
the bank select bits for data memory.
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.
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 the Z, C or DC bits from the STATUS register. For
other instructions, not affecting any Status bits, see the
“Instruction Set Summary.”
Note 1: The PIC16F716 does not use bits IRP
and RP1 of the STATUS register. Main-
tain these bits clear to ensure upward
compatibility with future products.
2: The C and DC bits operate as a borrow
and digit borrow bit, respectively, in
subtraction.
REGISTER 2-1: STATUS: STATUS REGISTER
Reserved Reserved R/W-0 R-1 R-1 R/W-x R/W-x R/W-x
IRP RP1 RP0 TO PD ZDCC
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7 IRP: This bit is reserved and should be maintained as ‘0’
bit 6 RP1: This bit is reserved and should be maintained as ‘0’
bit 5 RP0: Register Bank Select bit (used for direct addressing)
1 = Bank 1 (80h-FFh)
0 = Bank 0 (00h-7Fh)
bit 4 TO
: Time-out bit
1 = After power-up, CLRWDT instruction or SLEEP instruction
0 = A WDT time-out occurred
bit 3 PD
: Power-down bit
1 = After power-up or by the CLRWDT instruction
0 = By execution of the SLEEP instruction
bit 2 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
bit 1 DC: Digit Carry/Borrow
bit (ADDWF, ADDLW,SUBLW,SUBWF instructions), For Borrow, the polarity is
reversed.
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
bit 0 C: Carry/Borrow
bit
(1)
(ADDWF, ADDLW, SUBLW, SUBWF instructions)
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
Note 1: For Bo
rrow, the polarity is reversed. A subtraction is executed by adding the two’s complement of the sec-
ond operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high-order or low-order bit
of the source register.