First, are you realy using the 16F628 ?
Not the 16F628A ??

Note that the "Programming Specification" that
Olin is talking about is *NOT* the datasheet,
it *IS* the "Programming Specification", which
is a separate document.

Look at the specific webpage for the part you're
using, and you'll find it. *This* document is mostly
interesting for the ones who are designing programmers,
not for the everyday PIC developer...

On the page for the 16F628A there are links to
the following documents :

"PIC16F627A/628A/648A FLASH-Based 8-Bit CMOS Data Sheet"
http://ww1.microchip.com/downloads/en/DeviceDoc/40044F.pdf

"PIC16F627A/628A/648A EEPROM Memory Programming Specification"
http://ww1.microchip.com/downloads/en/DeviceDoc/41196g.pdf

In the later document on page 6 it says :

 > "If LVP is not being used for programming and the LVP
 > Configuration bit is set (i.e., LVP feature is enabled),
 > the PGM pin must not be allowed to toggle while
 > programming. The PGM pin is edge sensitive and if an
 > edge is detected during programming, it may cause the
 > PC to reset. If the LVP feature is disabled, the PGM pin
 > will have no effect on programming.
 >
 > Note: The LVP feature is enabled by default
 > when the LVP bit of the Configuration Word is set."

And that is repeated on other places in this document.

And again, "normal" developers should not have to read this,
since the developer of the programmer that is used *should*
have taken care of this in his design.

Best Regards
Jan-Erik.



Matthew Mucker wrote:
> Olin,
> 
> I was the one who originally asked the question.
> 
> I did read "the specs;" or at least section 14.13 of the datasheet for the
> PIC16F628, and I don't see anywhere in there that says, or even implies,
> that pulling pin 10 to ground is necessary.  
> 
> The reason for my question is that I couldn't find that in the specs,
> despite what some people were doing and/or were claiming is necessary.
> 
> In any case, it appears that pulling pin 10 to ground doesn't hurt, and may
> even help, programming this device. I have added a jumper to my programmer
> and have had no difficulty programming my part. I thank all of you for the
> input, I think the topic can be dropped now.
> 
> -Matthew
> 
>> -----Original Message-----
>> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On
>> Behalf Of Olin Lathrop
>> Sent: Monday, May 28, 2007 3:48 PM
>> To: Microcontroller discussion list - Public.
>> Subject: Re: [PIC] Using the P16Pro with LVP parts
>>
>> peter green wrote:
>>> Sure but if you erase and reprogram without ever leaving program mode
>>> this is not a problem.
>> But you can't on many PICs so this is a problem.  And then there are
>> PICs
>> that require Vdd before Vpp but can disable the MCLR function of the
>> Vpp
>> pin.
>>
>> I don't understand why people who clearly haven't read the programming
>> specs
>> are arguing how they think things should work, when there are people
>> who
>> have read the specs and have experience with this telling you how it
>> does
>> work.
>>
>>
>> ********************************************************************
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>> (978) 742-9014.  Gold level PIC consultants since 2000.
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