HP50G: USB BROWNOUT

[Harold Climer]

Has anyone found out anything more about this?
Harold A. Climer
Dept,Of Physics,Geology & Astronomy
U.T.Chattanooga
Room 318 Grote Hall
615 McCallie Ave
Chattanooga TN 37403
423-425-4546

[John H Meyers]

On Thu, 24 Aug 2006 11:53:51 -0500, Harold Climer wrote:

> Has anyone found out anything more about this?

It was only observed by people who:

o Deliberately connected a variable power supply
and slowly reduced the voltage, or

o Shut down a computer while 50G was drawing power from it.

When I plugged in and unplugged a USB cable many times,
there was no problem at all, as long as the "host"
remained turned on all the while
(has someone tried this while host remains turned off?
If that causes problem, then there's the problem!)

[r->] [OFF]

[Mike M.]

The other time I've seen it, is with a powered USB hub that has an
energy-saving mode - when no devices are plugged in, it powers down its
ports and the LED status lights go off. When you plug in a device, the
ports "wake up" and supply power to the connected device. However the
ports "wake" too slowly for the HP-50G and thus it will spontaneously
reboot when first connected to such a hub. If the hub already has some
other USB device connected and it is powered up already, there is no
problem.

I am hoping that a firmware update might be able to change the
threshold at which the 50G switches from batteries to USB power to
hopefully prevent this problem...

Regards,
Mike Mander