PIC18F2331_07 Datasheet, PDF (304/400 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers with nanoWatt Technology, High Performance PWM and A/D

PIC18F2331/2431/4331/4431
BTFSC
Bit Test File, Skip if Clear
Syntax:
[ label ] BTFSC f,b[,a]
Operands:
0 ≤ f ≤ 255
0≤b≤7
a ∈ [0,1]
Operation:
skip if (f<b>) = 0
Status Affected:
None
Encoding:
1011 bbba ffff ffff
Description:
If bit ‘b’ in register ‘f’ is ‘0’, then the next
instruction is skipped.
If bit ‘b’ is ‘0’, then the next instruction
fetched during the current instruction
execution is discarded, and a NOP is
executed instead, making this a two-cycle
instruction. If ‘a’ is ‘0’, the Access Bank
will be selected, overriding the BSR
value. If ‘a’ = 1, then the bank will be
selected as per the BSR value (default).
Words:
1
Cycles:
1(2)
Note:
3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Q2
Q3
Decode
Read
register ‘f’
Process
Data
If skip:
Q1
Q2
Q3
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1
Q2
Q3
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Q4
No
operation
Q4
No
operation
Q4
No
operation
No
operation
Example:
HERE
FALSE
TRUE
BTFSC
:
:
FLAG, 1
Before Instruction
PC
= address (HERE)
After Instruction
If FLAG<1> = 0;
PC
= address (TRUE)
If FLAG<1> = 1;
PC
= address (FALSE)
BTFSS
Bit Test File, Skip if Set
Syntax:
[ label ] BTFSS f,b[,a]
Operands:
0 ≤ f ≤ 255
0≤b<7
a ∈ [0,1]
Operation:
skip if (f<b>) = 1
Status Affected:
None
Encoding:
1010 bbba ffff ffff
Description:
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. If ‘a’ is ‘0’, the Access Bank
will be selected, overriding the BSR
value. If ‘a’ = 1, then the bank will be
selected as per the BSR value (default).
Words:
1
Cycles:
1(2)
Note:
3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Q2
Q3
Decode
Read
register ‘f’
Process
Data
If skip:
Q1
Q2
Q3
No
operation
No
operation
No
operation
If skip and followed by 2-word instruction:
Q1
Q2
Q3
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Q4
No
operation
Q4
No
operation
Q4
No
operation
No
operation
Example:
HERE
FALSE
TRUE
BTFSS
:
:
FLAG, 1
Before Instruction
PC
= address (HERE)
After Instruction
If FLAG<1> = 0;
PC
= address (FALSE)
If FLAG<1> = 1;
PC
= address (TRUE)
DS39616C-page 302
Preliminary
© 2007 Microchip Technology Inc.