Datasheet

 1998-2013 Microchip Technology Inc. DS30289C-page 221
PIC17C7XX
RETFIE Return from Interrupt
Syntax: [ label ] RETFIE
Operands: None
Operation: TOS  (PC);
0  GLINTD;
PCLATH is unchanged.
Status Affected: GLINTD
Encoding:
0000 0000 0000 0101
Description:
Return from Interrupt. Stack is POP’ed
and Top-of-Stack (TOS) is loaded in the
PC. Interrupts are enabled by clearing
the GLINTD bit. GLINTD is the global
interrupt disable bit (CPUSTA<4>).
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode No
operation
Clear
GLINTD
POP PC
from stack
No
operation
No
operation
No
operation
No
operation
Example:
RETFIE
After Interrupt
PC = TOS
GLINTD = 0
RETLW Return Literal to WREG
Syntax: [ label ] RETLW k
Operands: 0  k  255
Operation: k  (WREG); TOS  (PC);
PCLATH is unchanged
Status Affected: None
Encoding:
1011 0110 kkkk kkkk
Description:
WREG is loaded with the eight-bit literal
'k'. The program counter is loaded from
the top of the stack (the return address).
The high address latch (PCLATH)
remains unchanged.
Words: 1
Cycles: 2
Q Cycle Activity:
Q1 Q2 Q3 Q4
Decode Read
literal 'k'
Process
Data
POP PC
from stack,
Write to
WREG
No
operation
No
operation
No
operation
No
operation
Example:
CALL TABLE ; WREG contains table
; offset value
; WREG now has
; table value
:
TABLE
ADDWF PC ; WREG = offset
RETLW k0 ; Begin table
RETLW k1 ;
:
:
RETLW kn ; End of table
Before Instruction
WREG = 0x07
After Instruction
WREG = value of k7