PIC16F627A_05 Datasheet, PDF (121/180 Pages) Microchip Technology – Flash-Based, 8-Bit CMOS Microcontrollers with nanoWatt Technology

PIC16F627A/628A/648A
BTFSS
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example
Bit Test f, Skip if Set
[ label ] BTFSS f,b
0 ≤ f ≤ 127
0≤b<7
skip if (f<b>) = 1
None
01
11bb bfff ffff
If bit ‘b’ in register ‘f’ is ‘1’, then
the next instruction is skipped.
If bit ‘b’ is ‘1’, then the next
instruction fetched during the
current instruction execution, is
discarded and a NOP is executed
instead, making this a two-cycle
instruction.
1
1(2)
HERE
FALSE
TRUE
BTFSS
GOTO
•
•
•
REG1
PROCESS_CODE
Before Instruction
PC = address HERE
After Instruction
if FLAG<1> = 0,
PC = address FALSE
if FLAG<1> = 1,
PC = address TRUE
CALL
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example
Call Subroutine
[ label ] CALL k
0 ≤ k ≤ 2047
(PC)+ 1→ TOS,
k → PC<10:0>,
(PCLATH<4:3>) → PC<12:11>
None
10
0kkk kkkk kkkk
Call Subroutine. First, return
address (PC + 1) is pushed onto
the stack. The eleven bit imme-
diate address is loaded into PC
bits <10:0>. The upper bits of
the PC are loaded from
PCLATH. CALL is a two-cycle
instruction.
1
2
HERE CALL THERE
Before Instruction
PC = Address HERE
After Instruction
PC = Address THERE
TOS = Address HERE+1
CLRF
Syntax:
Operands:
Operation:
Status Affected:
Encoding:
Description:
Words:
Cycles:
Example
Clear f
[ label ] CLRF f
0 ≤ f ≤ 127
00h → (f)
1→Z
Z
00
0001 1fff ffff
The contents of register ‘f’ are
cleared and the Z bit is set.
1
1
CLRF REG1
Before Instruction
REG1 = 0x5A
After Instruction
REG1 = 0x00
Z
=1
© 2005 Microchip Technology Inc.
DS40044D-page 119