PIC16C620 Microchip Technology, PIC16C620 Datasheet - Page 66

• Manufacturer Part Number: PIC16C620
• Description: EPROM-Based 8-Bit CMOS Microcontroller
• Manufacturer: Microchip Technology

PIC16C62X
CLRWDT
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example
COMF
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example
DS30235G-page 66
Clear Watchdog Timer
[ label ] CLRWDT
None
00h
0
1
1
TO, PD
CLRWDT instruction resets the
Watchdog Timer. It also resets the
prescaler of the WDT. Status bits TO
and PD are set.
1
1
Before Instruction
After Instruction
Complement f
[ label ] COMF
0
d
(f)
Z
The contents of register 'f' are
complemented. If 'd' is 0 the result is
stored in W. If 'd' is 1 the result is
stored back in register 'f'.
1
1
Before Instruction
After Instruction
CLRWDT
COMF
00
00
f
[0,1]
WDT prescaler,
TO
PD
(dest)
127
WDT
WDT counter =
WDT counter =
WDT prescaler=
TO
PD
REG1
REG1
W
0000
1001
REG1,0
=
=
=
f,d
0110
dfff
=
=
0x13
0x13
0xEC
?
0x00
0
1
1
0100
ffff
Preliminary
DECF
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example
DECFSZ
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example
Decrement f
[ label ] DECF f,d
0
d
(f) - 1
Z
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
Before Instruction
After Instruction
Decrement f, Skip if 0
[ label ] DECFSZ f,d
0
d
(f) - 1
None
The contents of register 'f' are
decremented. 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)
Before Instruction
After Instruction
.
DECF
HERE
CONTINUE •
00
00
PC
CNT
if CNT =
PC
if CNT
PC
f
f
[0,1]
[0,1]
1998 Microchip Technology Inc.
127
127
(dest);
(dest)
CNT
Z
CNT
Z
=
=
=
=
0011
1011
CNT, 1
DECFSZ
GOTO
•
•
address
CNT - 1
0,
address CONTINUE
0,
address HERE+1
=
=
=
=
skip if result = 0
dfff
dfff
HERE
0x01
0
0x00
1
CNT, 1
LOOP
ffff
ffff