Olin,

LAY OFF THE GUY.

It is obvious that this 'program' is no more than a test snippet, trying to
solve the interrupt problem.

It hardly needs comments.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)


----- Original Message -----
From: Olin Lathrop <olin_piclist@COGNIVIS.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Wednesday, October 25, 2000 8:26 AM
Subject: Re: [PIC]:RB0/INT Configuration in 16C74B.


> >>
> Actually we are trying to configure RB0/INT pin in a 16C74B
> as an external interrupcion with no succeded.
>
> The program seems to ignore the external interruption and never run the
> service routine.
>
> Has anyone been experienced a similar situation, because we can not
> configure RB0/INT either as an output or as input.
>
> Our source code program is:
>
> ORG 000H
> GOTO MAIN
> ORG 004H
> GOTO SERVICE
> MAIN:
>      BSF STATUS, RP0
>      MOVLW 0XF1
>      MOVWF TRISB
>      MOVLW 07H
>      MOVWF ADCON1
>      BCF STATUS, RP0
>      BSF STATUS, RP0
>      BSF OPTION_REG, INTEDG
>      BCF OPTION_REG, 7
>      MOVLW b'10110000'
>      MOVWF INTCON
>
> PT1:  SLEEP
>      GOTO PT1
>
> SERVICE:
>      BSF PORTB,3
>      BCF INTCON, INTF
>      BCF INTCON, RBIF
>      RETFIE
> END
> <<
>
> You aren't setting the bank bits in the interrupt service routine, so
there
> is no guarantee what the current bank is when BSF PORTB, 3 executes in the
> interrupt routine.  This will require saving and restoring state.
>
> I also noticed that the first interrupt will disable the RB0 interrupt, so
> this will only happen once.  Of course we can't tell if that was
intentional
> since you haven't seen fit to document your code.  There may be other
> problems but I haven't wasted time looking at your main routine since it's
> not even important enough for you to comment properly.
>
>
> *****************************************************************
> Olin Lathrop, embedded systems consultant in Devens Massachusetts
> (978) 772-3129, olin@cognivis.com, http://www.cognivis.com
>
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>
>

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