On Sunday 11 September 2005 08:25 am, Olin Lathrop scribbled:
> Google is only partially right.  If you programmer doesn't pay attention to
> Vdd and Vpp order and sometimes Vpp rise time, then this can happen.  I
> just checked the 16F88 and 16F818/819 programming specs, and both of them
> require Vdd before Vpp and a fast rise time on Vpp.

But does Vdd-before-Vpp also imply a max time between these 2 events?  Or can 
Vdd be on for many seconds before Vpp comes on?


> It is always possible to completely erase and reprogram any properly
> functioning flash PIC regardless of the state it was previously programmed
> in.  There are usually two problems when this isn't working: The programmer
> doesn't perform the correct sequence or the external circuit is interfering
> in the case of in-circuit programming.

Exactamundo, and I'm would expect MPLAB to perform the correct sequence, which 
is why I'm trying to figure out the specifics of the various hardware 
options.  But I've run into much information that indicates problems and 
"finnicky" behaviour with programming the 16F818/9.

Cheers,
-Neil.


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