Hi, i've been trying to simulate a timer interrupt but it doesn't
work.  Anybody have any suggestion?  Based on the code elow tmrcounter
should increment on every interrupt so that i can calculate time more
than the 16 bit timer register.  The scale of the timer is 1:8. 
Thanks in advance.

	LIST		p=18f252
	INCLUDE		<p18f252.inc>

CounterA	equ	0x00
CounterB	equ 0x01
CounterC	equ 0x02
tmrcounter	equ	0x03
W_SAVE		equ	0x05
STATUS_SAVE equ 0x06

	ORG 0000H
                GOTO MAIN
                ORG 0008H
                GOTO INT_SERV

MAIN
	CLRF		PIR2,1   ;Register Overflow
	CLRF		TMR3H
	CLRF		TMR3L
                MOVLW		0x80
	MOVWF		INTCON
	MOVLW		0x02
	MOVWF		PIE2	;TMR3 Overflow Interrupt
	MOVLW		B'00110000'
	MOVWF		T3CON
	BSF		T3CON,0

	;  Loop for 1 second    
	movlw	D'26'
	movwf	CounterC
	movlw	D'119'
	movwf	CounterB
	movlw	D'87'
	movwf	CounterA
loop
	decfsz	CounterA,1
	goto	loop
	decfsz	CounterB,1
	goto	loop
	decfsz	CounterC,1
	goto	loop
	
	BCF	T3CON,0
	GOTO	FINISH

INT_SERV     ;Interrupt Routine

    MOVWF W_SAVE        ; save W
    SWAPF STATUS, W     ; save STATUS 
    MOVWF STATUS_SAVE

    INCF tmrcounter, 1                 ;increment on every overflow
 
    SWAPF 	STATUS_SAVE, W
    MOVWF 	STATUS; restore W and STATUS
    SWAPF 	W_SAVE, F
    SWAPF	W_SAVE, W     
    CLRF	                PIR2,1   ;	CLEAR Register Overflow

    RETFIE

FINISH
	END



>From  - wan
wanzulhelmi@gmail.com
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