> -----Original Message-----
> From: Eric Bohlman [SMTP:ebohlman@EARTHLINK.NET]
> Sent: Tuesday, November 05, 2002 12:19 AM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Corrupted flash on 877
>
> Last week a prototype of a 16F877-based instrument started acting crazy
> (naturally, this was while
> my client was demonstrating it at a trade show).  It was as if the code
> was running properly most
> of the time, but jumping to the wrong places occasionally (for example,
> menu items were getting
> written to the wrong line of the LCD).  When I got it back, I verified the
> chip and discovered that
> it verified at 5V but failed the low-voltage verify.  It was both
> programmed initially and verified
> on a Needhams EMP-11.  Erasing it and reprogramming it cured the problem.
> The EMP-11 uses the
> "production" algorithm, so the chip had to have passed a low-voltage
> verify when it was initially
> programmed.
>
> Has anyone seen anything like this before?  The chip has been programmed a
> few tens of times,
> nowhere near the write limit.
>
I've not seen this, but it's obviously quite concerning.  Did you use LVP or
normal high voltage programming?  If LVP do you have RB3 firmly tied to
ground?

Regards

Mike

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