> From: Olin Lathrop <
RemoveMEolin_piclist
TakeThisOuTembedinc.com>
> Subject: Re: [PIC] inputs on 18F4420
> To: "Microcontroller discussion list - Public." <
piclistEraseME
.....mit.edu>
> Date: Sunday, May 3, 2009, 6:24 AM
> alan smith wrote:
> > I have solid hardware working with a 16F887, least
> solid in the
> > fact the IO works fine. I took the same board, and
> replaced it
> > with a 18F4420, as its the only part I could identify
> that its pretty
> > much a drop in replacement, in as much as pin
> definitions, etc.
> >
> > So the code ports over, and with eliminating the page
> boundary calls
> > and other minor things, its cycling and doing its
> thing, almost.
>
> There are issues than pages to worry about. Pages is the
> easiest since they
> are essentially gone. Banking is easier, but still there.
> Then there are a
> lot of subtle things, like the rotate instructions having
> different names,
> and some instructions effecting status bits differently.
> Any GOTO $-1 will
> be broken as instructions now take two addresses instead of
> 1. All in all
> though, going from a PIC 16 to a PIC 18 is not too bad as
> long as the code
> was written responsibly in the first place.
>
> > The ports that are outputs work fine, the drive what
> they are supposed
> > to drive. But the inputs are not working, so thats
> what makes
> > me go hmmmmm......
>
> You forgot to turn off the A/D and/or the comparator.
>
>
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