Hi all,

I have a small production run of 60 boards using 16LF88s. Most are
working fine but after several firmware updates, I now have three or
four which can no longer be programmed, they always read all zeros for
the program memory. Examining the config word, I find the following:

Normal (programmable) PIC config word: 3F 35 3FFC
Abnormal PIC config word (on the few that will not program): 1E 35 3FFC

That is, there are two bits altered: flash AND data memory code
protect has been turned on.

There are two programmable devices on this board which are programmed.
The procedure is to erase the PIC, leave the board powered up
(including the PIC), program the other device (it is a Maxstream radio
module and IS connected to the PIC's pins but uses no high voltages in
programming), then program the PIC using MCLR (high voltage
programming - LVP is turned off in the config word).

Other than some weird bug with the PIC or a static problem, the only
thing I can think of is that somehow programming the Maxstream affects
the PIC sometimes, even though it doesn't place high voltage on MCLR.

Are there any known bugs which could cause this? Any ideas?

Thanks very much as always,

Sean
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