You have your microswitch connected to the LVP pin.  The PIC isn't
entering programming mode unless the LVP pin is held low.

Yes, yes, I know you have LVP turned off, but still, there it is.

Mike H.

On 4/20/06, Peter Todd <pete@petertodd.ca> wrote:
> I've got a minor project using a 16lf88 running at 3V with some LEDs
> attached to PORTA and PORTB and a microswitch to cycle between display
> patterns. Dead simple thing, a client just needed a mockup of a bike
> light. The circuit is equally simple, LEDs connected to ground and the
> pins, all LEDs setup to consume 5ma (white or red w/ resistor) The power
> source is two fresh 3V lithium's in parallel. Finally the normally open
> microswitch is connected between ground and RB5. I have the weak pullups
> enabled.
>
> The problem is that ICSP doesn't work unless the microswitch is pressed
> *down*. This happens even when the PIC is completely out of the circuit,
> and the only thing connected is the ICSP pins and my microswitch via
> jumper cables. (and the capacitor, I just soldered it on directly) This
> has happened with two seperate PIC chips and seems very reproducable.
> The programmer works fine on different code, but once I program the
> firmware in, I simply have to have that switch pressed down for ICSP to
> work.
>
> My quite short firmware is attached. I got everything working for the
> client, but I'd love to figure out what the root cause of this was.
>
>
> Incidentally, I think this is the first post I've made to piclist about
> pic chips rather than tricked-out scooters or very large numbers... I've
> been subscribed for about 6 months I think...
>
> --
> pete@petertodd.ca http://www.petertodd.ca
>
>
> --
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
>
>
>

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist