On November 23, 2005 02:49 pm, Barry Gershenfeld wrote:
> We have some claims that certain PIC parts have been turning up with
> bad programming.  As in, "It failed during burn in, so we reflashed
> it, and now it's fine".  This is the sum total of the research, so if
> you're thinking "hearsay" or "rumor", you may be close.   I have
> requested that any of these defective parts be sent to me so I can at
> least determine if we're talking bits, bytes, blocks, or the whole
> program segment.

You also need to ask which programmer was used.
Many programmers are okay for hobbyist use but are not intended as 
production quality programmers because they fail to verify at the test 
voltageS (yes, more than 1 voltage).

> What I want to know is, has anyone ever seen such a thing in the PIC
> line?

Heard about it with the Motorola 6811 and Hitachi 6811 (equivalents), 
but that was a while back concerning EEPROMs. Also heard Microchip had 
trouble with it's 1st flash versions which is why Atmel had a large 
lead on flash parts but I don't know if that is or was true and have 
nothing to back that up with.

> Does Microchip have anything to say about this?  I don't 
> recall seeing discussions of this nature, and that has me guessing
> that this isn't a real problem.

Usually, if you want to see promotional material, go to the 
manufacturer's website, and if you want to see negative pitfalls, you 
need to visit competitor's websites.

> I have seen similar discussions 
> regarding EEPROM's, but I think this is a little different.   I have
> had other issues with programming, but it never came down to the part
> "forgetting".
>
> FYI, favorite chips are 18F877A and 18F6621.  Promate III programmer,
> supposedly better than my ICD2.  Never had anything forget after
> using the ICD2.

Read the programming specs for the chips. They specify how they should 
be programmed and verified. If your programmer verifies at a few 
voltages, then that probably answers your question.
Many programmers are hobbyist quality, but there are a couple of 
exceptions that do production-quality programming and are supported by 
some people on this piclist.

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