PIC18F8520-I/PT Microchip Technology Inc., PIC18F8520-I/PT Datasheet - Page 61

• Manufacturer Part Number: PIC18F8520-I/PT
• Description: 80 PIN, 32 KB FLASH, 2048 RAM, 68 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F8520-I/PT

• A/d Inputs: 16-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 10 MIPS
• Eeprom Memory: 1024 Bytes
• Input Output: 68
• Interface: I2C/SPI/UART/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 80-pin TQFP
• Programmable Memory: 32K Bytes
• Ram Size: 2K Bytes
• Speed: 40 MHz
• Timers: 2-8-bit, 3-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part

4.13
The Status register, shown in Register 4-3, contains the
arithmetic status of the ALU. The Status register can be
the destination for any instruction, as with any other reg-
ister. If the Status register is the destination for an
instruction that affects the Z, DC, C, OV or N bits, then
the write to these five bits is disabled. These bits are set
or cleared according to the device logic. Therefore, the
result of an instruction with the Status register as
destination may be different than intended.
REGISTER 4-3:
 2004 Microchip Technology Inc.
Status Register
bit 7-5
bit 4
bit 3
bit 2
bit 1
bit 0
PIC18F6520/8520/6620/8620/6720/8720
STATUS REGISTER
bit 7
Unimplemented: Read as ‘0’
N: Negative bit
This bit is used for signed arithmetic (2’s complement). It indicates whether the result was
negative (ALU MSB = 1).
1 = Result was negative
0 = Result was positive
OV: Overflow bit
This bit is used for signed arithmetic (2’s complement). It indicates an overflow of the
7-bit magnitude, which causes the sign bit (bit 7) to change state.
1 = Overflow occurred for signed arithmetic (in this arithmetic operation)
0 = No overflow occurred
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, ADDLW, SUBLW and SUBWF instructions:
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
For ADDWF, ADDLW, SUBLW and 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
Legend:
R = Readable bit
- n = Value at POR
Note:
Note:
U-0
—
For borrow, the polarity is reversed. A subtraction is executed by adding the
2’s complement of the second operand. For rotate (RRF, RLF) instructions, this bit
is loaded with either bit 4 or bit 3 of the source register.
For borrow, the polarity is reversed. A subtraction is executed by adding the
2’s complement of the second operand. For rotate (RRF, RLF) instructions, this bit
is loaded with either the high or low-order bit of the source register.
U-0
—
U-0
—
W = Writable bit
‘1’ = Bit is set
R/W-x
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, MOVFF and MOVWF instructions are used to alter
the Status register, because these instructions do not
affect the Z, C, DC, OV or N bits from the Status regis-
ter. For other instructions not affecting any status bits,
see Table 24-1.
N
Note:
R/W-x
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
OV
The C and DC bits operate as a borrow
and digit borrow bit respectively, in
subtraction.
R/W-x
Z
x = Bit is unknown
R/W-x
DC
DS39609B-page 59
R/W-x
C
bit 0