On Sat, Sep 12, 2009 at 4:33 AM, cdb <colin@btech-online.co.uk> wrote:
> Why not, XOR the port bit in the ISR routine and not only save some
> typing, but also have the function in one place., or set a flag in the
> ISR and then XOR the port bit in your main code?


I did modify the code to have the ISR set a flag alone, rather than to
do any PORT I/O
The actual PORT I/O i do it in the indefinite loop.

Also changed the LED orientation, just to avoid the initial state of
PORTA being 0 and the LED to flash for a very short time at POWER up.

RB.0/INT pin is left unconnected to anything


So this is what i would expect:
no interrupts, since RB0 is left unconnected and hence LED doesn't light up.
Provide a trigger on RB0, LED lights for a short period and goes off.


But results do show otherwise:
on power up, LED is off, all is well.
i provide a trigger, high or low on RB.0 nothing happens. LED is off
all the time whatever i do.
Seems like the interrupt is not triggered ?


Still finding no clue on what's happening .. Any clues ?


Thanks


	PROCESSOR	16f72
	#include "p16f72.inc"
	
	__CONFIG _CP_OFF & _WDT_OFF & _PWRTE_ON & _HS_OSC

loopus_a	EQU 0x2d

loopms_a	EQU 0x2e
loopms_b	EQU 0x2f
loopms_c	EQU 0x30

flags		EQU 0x31


LEDPORT	equ	PORTA
LEDBIT	equ	1

	org	0x0
	goto	init

	org	0x4
	goto	isr

	#include "delays.inc"

init
	clrf	flags

	banksel	TRISA
	movlw	0x06
	movwf	ADCON1
	movlw	0x00			; Port A output
	movwf	TRISA

	movlw	0x01			; RB.0 int
	movwf	TRISB

	banksel	OPTION_REG
	bcf	OPTION_REG, INTEDG	; falling edge int
	bsf	OPTION_REG, NOT_RBPU	; disable pullup
	bsf	INTCON, INTE		; enable RB.0 int
	bsf	INTCON, GIE		; global int

	banksel	LEDPORT

main
	btfsc	flags, LEDBIT
	bsf	LEDPORT, LEDBIT		; LED on
	movlw	0xff
	call	delay_ms

	bcf	LEDPORT, LEDBIT		; LED off
	movlw	0xff
	call	delay_ms

	clrf	flags			; clear all flags
	goto	main

isr
	bcf	INTCON, INTF
	bsf	flags, LEDBIT
	retfie

	END
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