Just though this might save you some work

ENCODER_INT_HANDLER
    CLRWDT                                                      ; HIT THE
DOG
    MOVF     PORTB, W                                           ; GET THE
NEW ENCODER DATA
    MOVWF    NEW_ENCDR                                          ; SAVE IT
    RRNCF    OLD_ENCDR                                          ; ROTATE OLD
DATA INTO POSITION
    XORWF    OLD_ENCDR, F                                       ; XOR TO GET
DIRECTION
    BTFSC    OLD_ENCDR,4                                        ; WHICH
DIRECTION DID IT GO IN?
    BRA      CLOCKWISE                                          ; CLOCKWISE
COUNTERCLOCKWISE                                                ; COUNTER
CLOCKWISE
...
....
INT_EXIT
    MOVF    NEW_ENCDR, W
    MOVWF   OLD_ENCDR                                           ; SAVE NEW
ENCODER DATA TO OLD DATA
    CPFSEQ  PORTB
    BRA     ENCODER_ERROR
    BCF     INTCON,0                                            ; CLEAR
CHANGE ON PORT B INTERRUPT FLAG
    RETFIE  FAST
ENCODER_ERROR
    BSF     ERROR
    BCF     INTCON,0                                            ; CLEAR
CHANGE ON PORT B INTERRUPT FLAG

    RETFIE  FAST

Ive forgotten were A and B were connected to 4&5 I think. I've not included
the counting code which is fairly easy.

Set up int as change on PORTB (you have to do this or it will not work)

18series only

Tim



I was wondering if anyone had experience of using an optical encoder (A and
B inputs for quadrature mode) on a PIC microcontroller.
I'd like to use the A and B output of the optical encoder and tied into
PortB and have each pulse (either on A or B) trigger an interrupt.

Any help appreciated. Thanks.

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