Rockbox.org home
release
dev builds
extras
themes manual
wiki
device status forums
mailing lists
IRC bugs
patches
dev guide



Rockbox mail archive

Subject: RE: Archos Jukebox design flaw
From: Justin (jaf60_at_it.canterbury.ac.nz)
Date: 2003-01-08


>If your USB port strictly follows the spec, it is not possible to power a
>standard HDD, as 500mA just doesnt cut it (these drives draw ~ 1A when
>spinning up).
>So, this is one case where the Archos engineers did the right thing ....

Well, not really. At up to 500mA, USB delivers more power than many of
the archos power adpators can, and you can run the
Archos off the adaptors (the unit plays and charges simultaniously, and
the batteries handle the powerspikes when they happen), so why not power
it off the USB?

With a few design changes, the unit could run off USB, I imagine it
doesn't only because it's designwise, it's simpler to get an adaptor to
provide you with an easy voltage for the job, than it is to take a less
convenient and pre-determined voltage (USB 5V) and design your charging
system with that in mind.

As it happens, I seem to be plagued by unpowered USB hubs, so having the
archos run and charge off USB probably wouldn't be a huge advantage for
me, but I don't see that it shouldn't be done. In fact, I imagine I
could build a USB cable that has a normal USB plug that the computer
end, and terminates in a USB plug and a 9V DC plug, thus making it
possible to run and charge the unit from USB.

In fact, that cable almost sounds like a future Archos product... :-)



Page was last modified "Jan 10 2012" The Rockbox Crew
aaa