PIC18F2450 Datasheet, PDF (248/320 Pages) Microchip Technology – 28/40/44-Pin, High-Performance, 12 MIPS, Enhanced Flash, USB Microcontrollers with nanoWatt Technology

PIC18F2450/4450
SLEEP
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Q Cycle Activity:
Q1
Decode
Enter Sleep mode
SLEEP
None
00h → WDT,
0 → WDT postscaler,
1 → TO,
0 → PD
TO, PD
0000 0000 0000 0011
The Power-Down status bit (PD) is
cleared. The Time-out status bit (TO)
is set. Watchdog Timer and its
postscaler are cleared.
The processor is put into Sleep mode
with the oscillator stopped.
1
1
Q2
No
operation
Q3
Process
Data
Q4
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:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Q Cycle Activity:
Q1
Decode
SUBFWB f {,d {,a}}
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
(W) – (f) – (C) → dest
N, OV, C, DC, Z
0101 01da ffff ffff
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’ (default).
If ‘a’ is ‘0’, the Access Bank is
selected. If ‘a’ is ‘1’, the BSR is used
to select the GPR bank (default).
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 19.2.3
“Byte-Oriented and Bit-Oriented
Instructions in Indexed Literal Offset
Mode” for details.
1
1
Q2
Read
register ‘f’
Q3
Process
Data
Q4
Write to
destination
Example 1:
SUBFWB REG, 1, 0
Before Instruction
REG = 3
W
=2
C
=1
After Instruction
REG =
W
=
C
=
Z
=
N
=
FF
2
0
0
1 ; result is negative
Example 2:
SUBFWB REG, 0, 0
Before Instruction
REG = 2
W
=5
C
=1
After Instruction
REG =
W
=
C
=
Z
=
N
=
2
3
1
0
0 ; result is positive
Example 3:
SUBFWB REG, 1, 0
Before Instruction
REG = 1
W
=2
C
=0
After Instruction
REG =
W
=
C
=
Z
=
N
=
0
2
1
1 ; result is zero
0
DS39760A-page 246
Advance Information
© 2006 Microchip Technology Inc.