Vasile Surducan wrote:
> On 5/27/07, Bob Axtell <engineer@neomailbox.com> wrote:
>   
>> Matthew Mucker wrote:
>>     
>>> Greetings fellow hobbyists!
>>>
>>> I'm returning to the world of PICs after an absence of a few years.  While
>>> much has stayed the same I've found a few things that have changed.
>>>
>>> In particular, the 'F84 seems to have yielded to the 16F628 chip.  I've
>>> bought a few of these chips and have dusted off the old P16Pro programmer.
>>> >From my reading, some people seem to be suggesting that pin 10 of the PIC
>>> must be tied to ground to disable LVP on this device, so that I don't fry my
>>> part with high voltage programming.
>>>
>>> I've read the product's datasheet, and my interpretation of section 14.13 of
>>> the datasheet is that this isn't necessary.
>>>
>>> So I'm asking the community: do I have to ground pin 10 of the part during
>>> programming if I'm not using low voltage programming?
>>>
>>> Thanks,
>>>
>>> -Matthew
>>>
>>>
>>>       
>> You must force the LVP pin to GND while programming using high-voltage
>> mode, yes.
>>     
>
> Hmm. Are you sure ? If you are performing a HVP it does not matter
> what you've done with LVP pin as long LVP flag is kept disable.
>
> But a 10K
>   
>> resistor to GND will suffice.
>>     

But the NATURAL state of a NEW device is always to have LVP ENABLED. So 
without the
GND state, you can never reliably disable LVP in the first place. Not 
theory, this is fact. I've
programmed thousands of PIC16F88's, and half must be GND the first time 
in order to be programmed.

--Bob

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