Thanks!

This means that in LVP (that I really like...) I can't use MCLR as a input
at all!
Doing so would mean pulling it high and having a switch to Vss...  This
would cause a reset!
LOL !

Oh'well.  this means that I *have* to use the internal osc because I need
the pinns for IO.

    Kyrre


----- Original Message -----
From: "Bob Ammerman" <rammerman@ADELPHIA.NET>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Friday, November 08, 2002 5:01 AM
Subject: Re: [PIC]: Wierd thing about the 16F628 ???


> The '628 errata mentions that when LVP is enabled, MCLR is MCLR whether or
> not you want it to be (ie: regardless of the CONFIG value).
>
> See DS80073F - page 9, item 5.
>
> Bob Ammerman
> RAm Systems
>
> ----- Original Message -----
> From: "Kyrre Aalerud" <kreature@C2I.NET>
> To: <PICLIST@MITVMA.MIT.EDU>
> Sent: Thursday, November 07, 2002 4:24 PM
> Subject: [PIC]: Wierd thing about the 16F628 ???
>
>
> > Hi all!  I've been off the list for quite some time now and it's nice to
> be
> > back :-)
> >
> > To the point...
> >
> > There was something wierd the orther day about my 16F628 based
> prototype...
> > I could simply not get the thing to execute code!
> > After going through all the docs again I still hadn't found what was
wrong
> > so I did something that shouldn't have solved the issue according to
> specs.
> > I tied MCLR to VDD *even* if it was already tied to VDD internally.
(Yes,
> I
> > had disabled it because I didn't need it, and I was using LVP ICSP.)
> > Now, everything worked as it was supposed to?
> >
> > It doesn't say anything in the docs or programming guide that even when
> you
> > disable MCLR, you need top pull it high during startup to avoin entering
> > programming mode...  But that was what was happening!
> > Either that, or some limbo-state occurred.  I'm not sure about this as I
> > measured on the pinns while in this state, and some of them had 1.8v
2.1v
> > and 3.2v on them, and they were actually not attached to anything???
> > (Floating)
> >
> > I had previously made up a SCHAER compatible programmer that used MCLR
av
> > VDD control so that it would be compatible with LVP.    I did this based
> on
> > the info in the programming doc where it shows how to enter programming
> > mode.  Now I have adjusted the programmer a little more and so it will
now
> > do LVP ICSP with the circuit wired with MCLR high or pulled high.  It
even
> > works with ic-prog :-)
> >
> > Oh'well...  Turned out that a wierd little glitch stopped me dead for
many
> > hours...
> >
> > I'm posting this here, now, because I want to know if I misinterpreted
> > anything in the manuals or if others may have similar problems.  I have
> > already searched general usenet and the piclist archives without finding
> > anything, and so this might be helpful to others in the future...
> >
> > Oh, and if anyone is interested, I might post a schematic and PCB of the
> > little programmer i made on my homepage...  It uses 3-wire only +VDD/VSS
> and
> > does LVP mode only.  The whole thing fits in the DB25 connector and
> attaches
> > to the LPT-port.  (This might beling in a EE: but I'm to lazy to write 2
> > posts...)
> >
> > Just for the search engines in the future:
> > On the PIC16F628, MCLR have to be pulled high during startup, regardless
> of
> > wether it is enabled or not to avoid entering programming-mode or some
> other
> > limbo-state.
> >
> > --
> > http://www.piclist.com hint: To leave the PICList
> > mailto:piclist-unsubscribe-request@mitvma.mit.edu
> >
> >
>
> --
> http://www.piclist.com hint: To leave the PICList
> mailto:piclist-unsubscribe-request@mitvma.mit.edu
>
>
>

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