Datasheet

PIC17C4X
DS30412C-page 116  1996 Microchip Technology Inc.
BTFSS Bit Test, skip if Set
Syntax: [
label ] BTFSS f,b
Operands: 0 ≤ f ≤ 127
0 ≤ b < 7
Operation: skip if (f<b>) = 1
Status Affected: None
Encoding:
1001 0bbb 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 exe-
cution, is discarded and an NOP is exe-
cuted instead, making this a two-cycle
instruction.
Words: 1
Cycles: 1(2)
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Execute NOP
If skip:
Q1 Q2 Q3 Q4
Forced NOP NOP Execute NOP
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)
BTG Bit Toggle f
Syntax: [
label ] BTG f,b
Operands: 0 ≤ f ≤ 255
0 ≤ b < 7
Operation: (f<b>
) → (f<b>)
Status Affected: None
Encoding:
0011 1bbb ffff ffff
Description:
Bit 'b' in data memory location 'f' is
inverted.
Words: 1
Cycles: 1
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
register 'f'
Execute Write
register 'f'
Example:
BTG PORTC, 4
Before Instruction:
PORTC = 0111 0101 [0x75]
After Instruction:
PORTC = 0110 0101 [0x65]