Datasheet

PIC18F87K22 FAMILY
DS39960D-page 466  2009-2011 Microchip Technology Inc.
SLEEP Enter Sleep Mode
Syntax: SLEEP
Operands: None
Operation: 00h
 WDT,
0  WDT postscaler,
1  TO,
0  PD
Status Affected: TO, PD
Encoding: 0000 0000 0000 0011
Description: The Power-Down status bit (PD) is
cleared. The Time-out status bit (TO
)
is set. The Watchdog Timer and its
postscaler are cleared.
The processor is put into Sleep mode
with the oscillator stopped.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
Process
Data
Go to
Sleep
Example:
SLEEP
Before Instruction
TO
=?
PD
=?
After Instruction
TO
= 1 †
PD
= 0
† If WDT causes wake-up, this bit is cleared.
SUBFWB Subtract f from W with Borrow
Syntax: SUBFWB f {,d {,a}}
Operands: 0
f 255
d
 [0,1]
a
 [0,1]
Operation: (W) – (f) – (C
) dest
Status Affected: N, OV, C, DC, Z
Encoding:
0101 01da ffff ffff
Description: Subtract register ‘f’ and Carry flag
(borrow) from W (2’s complement
method). If ‘d’ is ‘
0’, the result is stored in
W. If ‘d’ is ‘
1’, the result is stored in
register ‘f’.
If ‘a’ is ‘
0’, the Access Bank is selected. If
‘a’ is ‘
1’, the BSR is used to select the
GPR bank.
If ‘a’ is ‘
0’ and the extended instruction
set is enabled, this instruction operates in
Indexed Literal Offset Addressing mode
whenever f
95 (5Fh). See
Section 29.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode”
for details.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register ‘f’
Process
Data
Write to
destination
Example 1:
SUBFWB REG, 1, 0
Before Instruction
REG = 3
W=2
C=1
After Instruction
REG = FF
W=2
C=0
Z=0
N = 1 ; result is negative
Example 2:
SUBFWB REG, 0, 0
Before Instruction
REG = 2
W=5
C=1
After Instruction
REG = 2
W=3
C=1
Z=0
N = 0 ; result is positive
Example 3:
SUBFWB REG, 1, 0
Before Instruction
REG = 1
W=2
C=0
After Instruction
REG = 0
W=2
C=1
Z = 1 ; result is zero
N=0