PIC18F4520ESLASHMLQTP datasheet(300/390 Pages) MICROCHIP

300 / 390 page

PIC18F2420/2520/4420/4520

DS39631A-page 298

Preliminary

 2004 Microchip Technology Inc.

RETFIE

Return from Interrupt

Syntax:

RETFIE {s}

Operands:

∈ [0,1]

Operation:

(TOS)

→ PC,

→ GIE/GIEH or PEIE/GIEL,

if s = 1

(WS)

→ W,

(STATUSS)

→ Status,

(BSRS)

→ BSR,

PCLATU, PCLATH are unchanged.

Status Affected:

GIE/GIEH, PEIE/GIEL.

Encoding:

0000

0001

000s

Description:

Return from interrupt. Stack is popped

and Top-of-Stack (TOS) is loaded into

the PC. Interrupts are enabled by

setting either the high or low priority

global interrupt enable bit. If ‘s’ = 1, the

contents of the shadow registers, WS,

STATUSS and BSRS, are loaded into

their corresponding registers, W,

Status and BSR. If ‘s’ = 0, no update of

these registers occurs (default).

Words:

Cycles:

Q Cycle Activity:

Decode

operation

POP PC

from stack

Set GIEH or

GIEL

operation

Example:

RETFIE

After Interrupt

TOS

BSR

BSRS

Status

STATUSS

GIE/GIEH, PEIE/GIEL

RETLW

Return literal to W

Syntax:

RETLW k

Operands:

≤ k ≤ 255

Operation:

→ W,

(TOS)

→ PC,

PCLATU, PCLATH are unchanged

Status Affected:

None

Encoding:

0000

1100

kkkk

Description:

W 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:

Cycles:

Q Cycle Activity:

Decode

Read

literal ‘k’

Process

Data

POP PC

from stack,

Write to W

operation

Example:

CALL TABLE ; W contains table

; offset value

; W now has

; table value

TABLE

ADDWF PCL

; W = offset

RETLW k0

; Begin table

RETLW k1

;

RETLW kn

; End of table

Before Instruction

07h

After Instruction

value of kn

PIC18F4520E/MLQTP Datasheet(PDF) 300 Page - Microchip Technology

PIC18F4520E/MLQTP Datasheet(HTML) 300 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL