IIRC LVP uses an alternate pin to the reset pin to activate reset mode, removing the need for a high-voltage signal. Sounds like, in this case, RA5 is the pin used for that purpose. Mike H On Fri, Jan 11, 2013 at 3:13 PM, Rupert Swarbrick wro= te: > Spehro writes: > >>> You might want to look at the states of all the relevant registers on > your > >>> debugger. > >> > >> Yep, they come up as the datasheet claims (of course). But the debugge= r > >> also thinks everything should work... > > > > Rather than MPSIM, can you use a hardware debugger? Otherwise you're > > working blind. Of course there is always the possibility it works only > > when debugging (usually some kind of initialization issue), > > I've been a bit busy at work, but finally found some time to spend on > this tonight. I realised that the Pickit3 does actually do debugging, so > played around with it a bit, only swearing slightly at the horrific Java > monstrosity that is MPLAB-X. > > Basically, it seems that the problem was enabling low-voltage > programming. I still don't understand why this interacted so strangely, > but disabling it seems to have fixed things. Grr. > > Thank you everyone for the really helpful responses! > > Rupert > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .