On Tue, Jun 15, 2004 at 03:38:06PM +0100, Michael Rigby-Jones wrote:
> >
> >On Sat, Jun 12, 2004 at 05:21:57PM +0200, Wouter van Ooijen wrote:
> >> > Wouter, I need some separation clarity from you here.
> >> >
> >> > I'm clear on the LVP pin problem when programming. See my other
> >> > post. But are you saying that there's a glitch issue when simply
> >> > using a HVP programmed
> >> > part with LVP config bit clear?
> >>
> >> Not when just running.
> >
> >OK. Clear. Sounds like another point for a bootloader. And I
> >now really agree with the point you have in the ZPL
> >documentation about not messing with the 18F config bits even
> >though they are writable.
> >
> >>
> >> But for the argument 'but I use a HVP programmer and my image has LVP
> >> disabled': note that when you reprogram the part you will
> >likely erase
> >> it as part of the programming process. And the erased state
> >of the LVP
> >> bit is?
>
>
> >-----Original Message-----
> >From: Byron A Jeff [mailto:byron@CC.GATECH.EDU]
> >Sent: 15 June 2004 15:02
> >To: PICLIST@MITVMA.MIT.EDU
> >Subject: Re: [PIC] PIC18F452 LVP pin needs to be tied low?>
> >
> >LVP on! As I said above I'm clear on the LVP pin problem when
> >programming. So the new wrinkle is ICSP. Even when doing HVP
> >only via ICSP one must make sure that the LVP pin doesn't float.
> >
> >Crystal clear now.
>
> Better muddy up the waters then!  The LVP "problem" is only a problem when
> programming the PIC above 4.5 volts.  If a PIC is being used in a 3.3volt
> application, it's only an issue the first time the device is programmed. (no
> bulk erase below 4.5 volts).

Um, does a Begin Erase command not apply to the configuration memory?
Nothing in the 16F88 progspec indicates that you cannot erase the config memory
area, just that the CP bit cannot be erased. But it's unclear if the LVP bit
can be erased at 3.3V Vdd but a normal 13V Vpp. If so you're still in the
same boat.

Clarity preserved. ;-)

BAJ

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