Vasile Surducan wrote:

> 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.

The critical part is the phase between the "erase all" (that
most programmers perform as the first step) and the re-flashing
of the part. If the programming software/firmware/hardware is
keeping the target device in programming mode (MCLR at Vpp level)
without dropping it back it should be safe to leave the LVP
pin floating. If not, you'd better pull it low.

> Indeed. But is necessary only the LVP bit is enabled...

Which is what the "erase all" does, enables LVP...

LVP is not re-disabled until the CONFIG bits are
re-programmed, often as the last step in the programming
process. If MCLR at any time during this process is
dropped from the Vpp level, you have a slight risk
that the device will go into LVP mode, if the LVP
pin is not held low.

Note, there might be devices with have LVP disabled
*by deafult* (that is "erased", but enabled have been
the default on most types, as far as I know...

Jan-Erik.

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