Martin,

That was apparently the problem. I didn't see any significant glitch with
the scope, but found that using a larger USB cable and moving the
PICKIT3+circuit far from the noisy computer/TFT and backend instruments,
the required voltage went down to 3.05V with repeatable results.

So it looks like I will have to pay more attention to the environment
before programming parts, or use a custom Faraday cage for the task.

Thanks for the insight.

Ariel Rocholl


On Tue, Mar 11, 2014 at 2:21 PM, Martin Klingensmith <mklingen@mit.edu>wrot=
e:

> On 3/11/2014 9:15 AM, Ariel Rocholl wrote:
> > Martin,
> >
> > Yes, capacitors, layout and power is according to MCHIP requirements (s=
ee
> > my answer to Alan).
> > Perhaps the only difference is ICD3, being a reliable option when
> compared
> > to Pickit3.
> >
> > Regards,
> > Ariel Rocholl
>
> My only other guess would be ringing on the PGC or PGD line[s]
> Perhaps a higher voltage improves the rise time or raises the ringing
> above the threshold.
> You can probe the programming lines and see what they look like on a
> scope (10x)
>
> -
> Martin K
> --
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