PIC16F193X Datasheet, PDF (52/418 Pages) Microchip Technology – 28/40/44-Pin Flash-Based, 8-Bit CMOS Microcontrollers with LCD Driver and nanoWatt Technology

PIC16F193X/LF193X
2.2.3.1 STATUS Register
The STATUS register, shown in Register 2-1, contains:
• the arithmetic status of the ALU
• the Reset status
• the bank select bits for data memory (SRAM)
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 2-1: STATUS: STATUS REGISTER
U-0
—
bit 7
U-0
U-0
R-1/q
—
—
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).
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 Section 26.0
“Instruction Set Summary”).
Note 1: The C and DC bits operate as Borrow and
Digit Borrow out bits, respectively, in
subtraction.
R-1/q
PD
R/W-x/x
Z
R/W-x/x
DC⁽¹⁾
R/W-x/x
C⁽¹⁾
bit 0
Legend:
R = Readable bit
u = bit is unchanged
‘1’ = Bit is set
W = Writable bit
x = Bit is unknown
‘0’ = Bit is cleared
U = Unimplemented bit, read as ‘0’
-n/n = Value at POR and BOR/Value at all other Resets
q = Value depends on condition
bit 7-5
bit 4
bit 3
bit 2
bit 1
bit 0
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 (ADDWF, ADDLW,SUBLW,SUBWF instructions)⁽¹⁾
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⁾ (ADDWF, ADDLW, SUBLW, SUBWF instructions)⁽¹⁾
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 Borrow, the polarity is reversed. A subtraction is executed by adding the two’s complement of the
second operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high-order or low-order
bit of the source register.
DS41364A-page 50
Preliminary
© 2008 Microchip Technology Inc.