Not really. The idea of powering a chip via an I/O pin will
always cause damage. It means voltage as specified by the datasheet of
the component.

It is your choice, but, it will cause damage to the part.

If you power a system form one power source, it is not hard to do. Using
two power sources that are not synchronized with each other, that is where
the issue comes into play.

Gerald


On Mon, Feb 24, 2014 at 10:13 AM, <[email protected]> wrote:

> > No voltage can be applied to any pin when the board is not powered.
> >
> This is a *very* difficult condition to satisfy in any sort of real
> world application.  If you're using the Beaglebone to measure and/or
> monitor something it's almost certain that the 'something' will be
> there and turned on whether or not the Beaglebone is turned on.
>
> OK, there are ways of doing it, but it's not easy.  Even if inputs are
> clamped in some way, some voltage will almost certainly appear on the
> BBB inputs.
>
> So, what does 'No voltage' mean?  If it really means zero volts then
> it really is impossible.  Is there not be some (low) voltage that the
> inputs will tolerate even when the Beaglebone isn't powered up?  Most
> chip specs tend to specify about 0.5 volts above and below the supply
> voltage so this would mean + or - 0.5 volts from zero when the
> Beaglebone isn't powered.
>
> --
> Chris Green
> ยท
>
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