Ok. Now I am using the PIC16CE624 to monitor 8 data
lines by software polling. Memory location called
Result is used to store the states of the I/O pins
with a special condition. In any event say data line 2
is toggled from a low to a high, bit 2 of Result will
be toggle to a '1'. Upon a key press from the PC, the
data in Result will be transferred via RS232 to the PC
and displayed on the VB terminal. Pull-up resistors
are activiated and a logic '0' on the pin is simulated
by having that pin tied to gnd.

Problem now is that by comparing the states of the
data lines and the received ASCII code on the VB
terminal. Sometimes they match and are expected
results, sometimes, a wrong ASCII code with respect to
the current data lines state is sent instead.

Eg of a correct case, 'w' is received on VB and the
data lines are '01110111'. Hence I will like to find
out does polling of the PORTB using movf PORTB,will
have any hidden implications?

Thank

Poll    bcf     STATUS,RP0     ; selecting bank0 cos
PORTB in bank 0
          movf    PORTB,W        ; polling of PORTB
          movwf   Result              ; move current
state to general register Result
--- Olin Lathrop <olin_piclist@EMBEDINC.COM> wrote:
> > Poll    bcf     STATUS,RP0
> >         movf    PORTB,W
> >         movwf   Result
> >         iorwf   Result,F
>
> Your description was too muddled for me to follow,
> so I'm not sure what you
> are trying to do.  You should also add comments.
> That shows you've at least
> taken one of the minimum steps to fixing this
> yourself, and lets us know
> your intent.
>
> The only effect of the IORWF instruction is to set
> the Z bit if the value in
> RESULT is zero.
>
>
>
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