PIC14000-04 Datasheet, PDF (96/153 Pages) Microchip Technology – 28-Pin Programmable Mixed Signal Controller

PIC14000
CLRWDT
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example
Clear Watchdog Timer
[ label ] CLRWDT
None
00h → WDT
0 → WDT prescaler,
1 → TO
1 → PD
TO, PD
00 0000 0110 0100
CLRWDT instruction resets the Watch-
dog Timer. It also resets the prescaler
of the WDT. Status bits TO and PD
are set.
1
1
CLRWDT
Before Instruction
WDT counter =
After Instruction
WDT counter =
WDT prescaler =
TO
=
PD
=
?
0x00
0
1
1
COMF
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example
Complement f
[ label ] COMF f,d
0 ≤ f ≤ 127
d ∈ [0,1]
(f) → (dest)
Z
00 1001 dfff ffff
The contents of register 'f' are comple-
mented. If 'd' is 0 the result is stored in
W. If 'd' is 1 the result is stored back in
register 'f'.
1
1
COMF
REG1,0
Before Instruction
REG1 =
After Instruction
REG1 =
W
=
0x13
0x13
0xEC
DECF
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example
Decrement f
[ label ] DECF f,d
0 ≤ f ≤ 127
d ∈ [0,1]
(f) - 1 → (dest)
Z
00 0011 dfff ffff
Decrement register 'f'. If 'd' is 0 the
result is stored in the W register. If 'd'
is 1 the result is stored back in register
'f'.
1
1
DECF CNT, 1
Before Instruction
CNT =
Z
=
After Instruction
CNT =
Z
=
0x01
0
0x00
1
DECFSZ
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example
Decrement f, Skip if 0
[ label ] DECFSZ f,d
0 ≤ f ≤ 127
d ∈ [0,1]
(f) - 1 → (dest); skip if result = 0
None
00 1011 dfff ffff
The contents of register 'f' are decre-
mented. If 'd' is 0 the result is placed in
the W register. If 'd' is 1 the result is
placed back in register 'f'.
If the result is 0, the next instruction,
which is already fetched, is discarded. A
NOP is executed instead making it a two
cycle instruction.
1
1(2)
HERE
DECFSZ
GOTO
CONTINUE •
•
•
CNT, 1
LOOP
Before Instruction
PC = address HERE
After Instruction
CNT = CNT - 1
if CNT = 0,
PC = address CONTINUE
if CNT ≠ 0,
PC = address HERE+1
DS40122B-page 96
Preliminary
© 1996 Microchip Technology Inc.