> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]On Behalf
> Of William Chops Westfield
> Sent: 31 December 2006 21:00
> To: Microcontroller discussion list - Public.
> Subject: Re: [PIC] Code protection for 3V operation
> 
> 
> 
> On Dec 31, 2006, at 5:06 AM, Gerhard Fiedler wrote:
> 
> > can't you use 5V programming in a 3V circuit? Like making
> > the rest of the circuit 5V tolerant or creating some kind
> > of separation between the micro and the rest...
> 
> Hmm.  Suppose the rest of the circuit is NOT 5V tolerant, but
> you DO manage to isolate the PIC power, and the programming
> pins are dedicated to the programming function (NOT also
> connected to non-5V parts.)  Do any of the other PIC pins
> become outputs with 5V present at any time during programming?
> (that is, if your circuit is NOT 5V tolerant, how much isolation
> do you really need to do?)
iirc all the ordinary IO lines are hi-z when in programming mode so nothing special should be needed there.

you may need to watch out with some of the more specialist perhiperals though (for example on a USB pic make sure you connect Vusb to a supply that won't be raised to 5V).


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