At Fri, 9 Aug 2019 21:14:50 -0500 [email protected] wrote:

> 
> 
> As I said, P1-Pin-1 and the microUSB connector power are two different
> inputs to two different power supplies.  Having power on both of them is
> not a problem, and in fact, will prevent the problem of instability I was
> concerned about.
> 
> So, no problem powering both.
> 
> The concern with the random crashes is just that, it could take three days,
> or could happen in the first hour.
> I would power the unit from both pins, if it is doing something at all
> important.
> 
> Of course, my crashing experience is from 18 months ago, and there have
> been a lot of software releases since then.

So you believe it was some sort of software issue, rather than a hardware 
design problem?

> 
> I would encourage you to run some endurance tests on your board, before
> putting it in service.

OK, I can do that at some point.

> 
> --- Graham
> 
> ==
> 
> On Fri, Aug 9, 2019 at 8:34 PM Robert Heller <[email protected]> wrote:
> 
> > At Fri, 9 Aug 2019 16:23:26 -0700 (PDT) [email protected]
> > wrote:
> >
> > >
> > >
> > >
> > > Robert:
> > >
> > > It has been a while, almost a year since I did any testing with the
> > > PocketBeagle.
> > > But I don't think anything has changed relative to my comments below.
> > > Maybe someone can correct me if I am wrong, and some things have been
> > fixed.
> > >
> > > P1-Pin-1 is Vin, and is equivalent to the Barrel Jack input on the
> > > Beaglebone Black, it
> > > is a separate power supply input, and is isolated from the microUSB
> > > connector power.
> > >
> > > P1-Pin-7 is hardwired to the +5 pin on the microUSB connector, USB Port
> > 0.
> > > It is not clear from the schematic, but is visible if you view the PCB
> > > board plots.
> > > Or check it with an Ohmmeter.
> > >
> > > I found that the PocketBeagle, when powered exclusively by P1-Pin-1
> > would
> > > randomly
> > > crash about once every 24 hours of operation, without any apparent
> > reason,
> > > or
> > > any clue in the logs. I hope that this has been fixed, but I have seen
> > > other reports
> > > since I initially reported it, and nothing since that reported a fix.
> >
> > Well, I am not expecting an application that would run 24/7.  I am working
> > on
> > model RR control circuits.  It does not sound like this should be an
> > immediate
> > problem.
> >
> >
> > >
> > > The only workaround I found was to power P1-Pin-1 and P1-Pin-7 in
> > parallel,
> > > in which case
> > > it does not crash, but now there is no isolation between USB +5V and
> > your
> > > independent
> > > PB power supply, and, as you are concerned about, all kinds of
> > cross-feed
> > > and back
> > > powering can occur.
> >
> > That does not sound like a really good idea.
> >
> > Question: if the board was powered from P1-Pin-1 *and* the USB will there
> > be
> > problems?  Right now, that is my main concern.  Jacking in the USB (for
> > file
> > transfer mostly, since I can use the serial console for debugging) while
> > the
> > board is being powered via P1-Pin-1 is something I'd like to be able to
> > do,
> > but don't want to fry anything.
> >
> > >
> > > I suggest you read the email thread "PocketBeagles are Unstable" started
> > > 11/24/2017
> >
> > Will have a look.
> >
> >
> 

-- 
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