----- Original Message ----- From: Kyrre Aalerud To: Sent: Tuesday, June 22, 2004 11:47 PM Subject: Re: [PIC]: Self-programming via rs232 of the 16F88 ? > I was planning on using a different approach actually. > Programming the flash would be a password-protected option in the regular > rs232 comm dialog. > There would not be a bootloader of such. The loader function will be at the > very last block of memory (small loader I > will write myself...) and the only thing that will be done is dump the > incoming data onto the program memory up to the point of the loader. > > I realize now that this method could cause the program to be corrupted and > thus, I would not have any means of entering the loader again... > I would need a short loader init or something that would not be reprogrammed > so that I would have a way of entering rs232 programming at startup. I > guess waiting a timeout value for a character on the rs232 would be > suffichient... Maby as simple as the character F for "flash"... If it is > received upon powerup, go directly to the flash routine and ask for a > password before beginning flash programming. Only programming and > verifcation would be needed I think. No need to add advanced stuff like > crc's and stuff. > > Hmm... Reset is at 0000 as usual and interrupt is at 0004. To have the > most effichient interrupt routine I would like to stay clear of that area. > It does seem however that I can protect the first memory page from ever > being written internally and that is the smallest block I can protect like > that. It will allow me to reprogram the rest of the memory even with the > entire chip code protected, but I will have to select a new interrupt > vector. This means I will also have to include the context-saving in the > protected section to be sure I save the right data. > > Hmm, this will be fun!!! > > > Kyrre The XCSB pro compiler comes with a bootloader (including source) for the 88. Regards Sergio Masci http://www.xcprod.com/titan/XCSB - optimising PIC compiler -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.