Ahhh! the light dawns... I had wondered about that as well... Thanks for the paradigm shift. James Newton, PICList Admin #3 mailto:jamesnewton@piclist.com 1-619-652-0593 phone http://www.piclist.com ----- Original Message ----- From: Mike Harrison To: Sent: Friday, July 13, 2001 05:24 Subject: Re: [PIC]: code protect issues On Fri, 13 Jul 2001 08:44:45 +0300, you wrote: >> first rom page not protected on 505 > >Roman, this is a 'feature' partially shared with other popular micros. See >the programming data sheet for your chip, it explains what is protected >and what not. 12C508 also has a similar problem. I am completely stumped >as to why they did this. To allow code-protected devices to be customised by further programming of the unprotected area >The reset vector readable ? Why not - this is not an issue on the PIC, as even if you did manage to insert your own code you could not extract information from the protected area. >All subroutines ? Subroutines are the only way to do lookup tables in the low-end parts, so yes, of course subroutines! If you want to protect a subroutine, just put a GOTO to the body of your routine in page zero. >Cool (NOT). Should have put the readable window at the top (last page) if >at all imho. Not as useful, as post-protection programming of lookup tables would be tricky and inefficient to implement. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu