Reinhard Daemon wrote 2011-08-11 10:05: > Jan-Erik Soderholm telia.com> writes: > >> >> Note that this has been like this a long time even >> with the "5V-parts" that runs down to 2V-something. >> >> They usualy needs at least 4.5V to "bulk erase". They >> *can* erase flash at lower voltages, but not *bulk* erase. >> >> 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. >> >> Jan-Erik. >> >> 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 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 > the configuration settings of the programmer in MpLab). Yes, but I'm quite sure that what they mean with that is a bulk erase. What could work is some kind of boot-loader. They never do a bulk-erase (since that would erase the boot-loader itself) but the page-mode erases that usualy/sometime works at lower voltages. So if re-programming at low voltages is a definite need, a boot-loader could be a solution. > > 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 o= nce Yes, since that is "bulk erased" from factory. It doesn't matter if *your* bulk erase fails... :-) > (... but we have chosen a *flash* device and not an OTP, hihi). > > reinhard > > > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .