Jan-Erik Soderholm <jan-erik.soderholm <at> telia.com> writes:

>=20
> Note that this has been like this a long time even
> with the "5V-parts" that runs down to 2V-something.
>=20
> They usualy needs at least 4.5V to "bulk erase". They
> *can* erase flash at lower voltages, but not *bulk* erase.
>=20
> Sometimes it is possible to use other erase methods, but
> it is normaly only bulk-erase that clears the CONFIG bits.
> And then the only way to un-lock a read-protected chip.
>=20
> Jan-Erik.
>=20
> Robert Berger wrote 2011-08-10 17:34:
> > Hi,
> >
> > There seems to be a major design flaw with low voltage processors/tools
> > from Microchip, since when you use Real-ICE with a PIC18LF45K22 <at> 1.=
8V
> > it's unable to perform a bulk erase (needs at least 2.7V).
> >
> > Which means you write code - download it on an erased chip, make a code
> > change, try to reprogram and it does not work, since the real-ice can
> > not bulk erase the chip at 1.8V. (needs>  2.7V)
> >
> > I need 1.8V to interface with a main board, so I'm considering to cook
> > one board with voltage translators, so I can run the PIC with 3.3 V or
> > so and everything will (hopefully) work.
> >
> > ... but like this I could use another chip from a different manufacture=
r
> > as well ...
> >
> > My initial reason to use the PIC18LF45K22 was it's capability to work
> > with 1.8V.
> >
> > What's your experience with PICs and development at 1.8V and what's you=
r
> > work around for the problem above.
> >
> > Please advise,
> >
> > Robert..."Hardware, n.: The parts of a computer system that can be
> > kicked." - unknown
> >
> > My public pgp key is available at:
> > http://pgp.mit.edu:11371/pks/lookup?op=3Dget&search=3D0x90320BF1
> >
> >


Hello Jan-Erik,

i am working together with Robert on the project.
Just to make it clear:
The configuration bits are once set and are fine.
We do not alter them, we just update the program code and for
doing so *erase* should be enough ("erase before program" is set in=20
the configuration settings of the programmer in MpLab).

We would just need to reprogram the programm code (not ID, EEPROM, CONFIG,.=
...)
@ 1.8 V with RealICE.
But as Robert already stated, we are only able to programm a fresh chip onc=
e
(... but we have chosen a *flash* device and not an OTP, hihi).

reinhard



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