Total power from USB

[Tiago Marques]

It's an Iomega 160GB, which has a seagate drive inside, not sure which one.

http://www.iomega.com/about/prreleases/2008/041708_media_xporter.html

As I said in the previous e-mail, the drive works fine, it just doesn't do
so when I have other devices plugged, which I understand may be normal given
the total power I am pulling of the XO 1.5. I just wanted to know if you
were are of that(and that SD cards take a toll on that power), because it
could be some kind of design flaw that wasn't detected. If it is a known
"problem", then it's all good :)

Best regards,
Tiago

On Sat, Apr 24, 2010 at 11:19 PM, Paul Fox <pgf at laptop.org> wrote:

> tiago wrote:
>  > I forgot to mention that's not my case since even if I plug the two USB
> ends
>  > it still can't power up.
>
> on either XO model the extra cables won't make a difference -- all the
> power (1A available total) is available to any port.  does your drive
> work on an XO-1?  do you have power consumption specs for your drive?
>
> paul
>
>  >
>  > Best regards,
>  > Tiago
>  >
>  > On Sat, Apr 24, 2010 at 7:42 PM, Sameer Verma <sverma at sfsu.edu> wrote:
>  >
>  > > On Sat, Apr 24, 2010 at 4:55 PM, Tiago Marques <tiagomnm at gmail.com>
> wrote:
>  > > > Hi all,
>  > > > I've ran into something on the 1.5 B2 I have here, which I'm in
> doubt if
>  > > may
>  > > > or may not be relevant for OLPC's hardware people(it seems not), so
> I'm
>  > > > reporting it anyway.
>  > > > All three USB ports can deliver enough power to an USB 2.5" HDD, no
>  > > problem.
>  > > > They cannot in the following conditions:
>  > > >  - An extra SD card is plugged in
>  > > >  - Another USB device is plugged in one port, even one of lower
> power
>  > > like a
>  > > > flash drive. (sometimes it only takes one, sometimes it takes two,
> SD
>  > > card
>  > > > power also seems to be an issue)
>  > > > When I try to plug in the 2.5" HDD, it doesn't have enough power to
>  > > spindle
>  > > > at enough speed and sits there trying to start itself.
>  > > > When plugging in an USB device or SD card after the 2.5" HDD is
> already
>  > > > working, it suffers a loss of power and enters the restarting state.
> This
>  > > is
>  > > > true if the SD card is plugged in instead(with another USB device
>  > > present),
>  > > > which suggests me that the power is shared.
>  > > > No other plugged devices seem to be rendered temporarily
> unaccessible due
>  > > to
>  > > > the power failure on the high power device.
>  > > > Best regards,
>  > > > Tiago
>  > > > _______________________________________________
>  > > > Devel mailing list
>  > > > Devel at lists.laptop.org
>  > > > http://lists.laptop.org/listinfo/devel
>  > > >
>  > >
>  > > I see a similar issue with a Lacie drive on my Dell desktop. This
>  > > drive actually comes with a cable that has two USB cables to draw
>  > > power from two ports. With two ports, the platter spins without any
>  > > problem. With one port, the disk clicks on the Dell.
>  > >
>  > > On a XO-1 G1G1, XO-1.5 B2 and XO-1.5 C2 I am able to power the same
>  > > drive via one port only both with a SD card and without a SD card. The
>  > > issue may very well be the USB drive power draw. I am using a LACIE
>  > > Design by FA Porsche http://bit.ly/9HD5uI
>  > >
>  > > This will be important for XS-on-XO scenarios, where we would
>  > > piggyback the /library partition onto an external drive.
>  > >
>  > > cheers,
>  > > Sameer
>  > >
>  > > --
>  > > Dr. Sameer Verma, Ph.D.
>  > > Associate Professor, Information Systems
>  > > Director, Campus Business Solutions
>  > > San Francisco State University
>  > > http://verma.sfsu.edu/
>  > > http://cbs.sfsu.edu/
>  > > http://is.sfsu.edu/
>  > >
>  > part 2     text/plain                 129
>  > _______________________________________________
>  > Devel mailing list
>  > Devel at lists.laptop.org
>  > http://lists.laptop.org/listinfo/devel
>
> =---------------------
>  paul fox, pgf at laptop.org
>
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