Jan-Erik Soderholm writes:

> The O.P. wrote :
> 
> > Although these devices [12Fxxx] are not billed
> > as LVP devices, it seems as if they do not need the 13V 
> > of the more typical HVP devices.  They seem to be HVP
> > flash memory, but include an internal high voltage generator.
> > If I'm understanding this correctly, it eliminates the need for
> > that pesky 13V source!
> 
> I still think that is a statement based on a missunderstanding
> of the 12Fxxx data sheet. I don't think the 12F's are any
> different then any other (modern) Flash PICs in this regards
> (the need for a high voltage source/signal to use HVP).

Well, I'm the OP, the newbie, so you should take those statements with
a grain of salt!  Those comments were made after reading the
"PIC12F629/75/PIC16F630/76 Memory Programming Specification"
(41191C.pdf on the microchip website.)

Specifically, note 1 at the bottom of page 2:

Note 1: In the PIC12F629/75/PIC16F630/76, the programming high voltage
is internally generated. To activate the Programming mode, high
voltage needs to be applied to the MCLR input. Since the MCLR is used
for a level source, the MCLR does not draw any significant current.

And then from interpretation of the table on page 20:

Sym   Characteristics            min          max     units

VIHH  High voltage on MCLR for   VDD + 3.5    13.5    V
      Programming mode entry

Now, my interpretation of Note 1 is that internally VDD is raised to
the necessary programming voltage for flash memory.  My guess is that
if this can be done on the most inexpensive chips in the line, it
would be something they would use across the line of modern units.

-p.
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