Wolfram Liebchen wrote:
>
> Does anyone know, if there is danger of erratic PC increment
> caused by an interrupt during a MOVWF PCL ?
> The application note AN556, concerning table reads / computed GOTO
> on a PIC 16Cxx device, says, that one has to disable interrupts to
> prevent the computed GOTO from jumping one instruction too far.
>
> The data book (at least for PIC 17C42) says, that increment of PC
> is inhibited after GOTO, CALL, RETURN... and MOVWF PCL. So then, there
> should be no danger?
> Or even worse, an interreupt during a normal GOTO could also cause a
> false jump ?!?
>
> I would like to hear, if anyone has tested for this problem.
>

The information in AN556 is incorrect. You do not need to disable interrupts
in computed GOTOs.

Scott


P.S.
Andy W., I just checked your PIC question 5. It still references AN576.