Hi Mark
--- In wrote:
>
>
> You could test this theory with a hefty external 5 volt supply. JP7
> shorts the input supply directly to the on-board 5 volt bus, bypassing
> the on-board 5 V regulator. In this configuration, you are depending
> on the capability of the external supply, not the on-board regulator.
> See section 5.11 of the TS-7260 manual.
>
> I expect that the answer is "do nothing". If you provide the drive with
> external power, I would expect that it would not draw a lot of power
> from the USB port. Otherwise, why would the drive have an external
> power input? Or have I missed something?
>
> Mark S.
>
You are absolutely right. Now that I have bought an external 5V supply
for my USB Hard Disk, there is no longer a hardware
"panic" either when the device is hotplugged or during hard boot. Yipppee.
So I guess that the problem does lie with the "charge pump" circuitry
on the 7260 being unable to cope with large current surges.
As mentioned in my earlier posting, it's a shame that the on-board
power circuitry didn't start by regulating the input voltage to 5V and
then to 3.3V and 1.8V. This would have been a neater and more
consistent approach, as it would still have allowed the provision of
an off-board regulated 5V supply (for those situations where it was
appropriate). But, hey ho, it's not actually such a big deal for me,
as I will only need the hard disk during development.
Many thanks for everyone's suggestions.
Cheers,
Philip
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ts-7000/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/ts-7000/join
(Yahoo! ID required)
<*> To change settings via email:
<*> To unsubscribe from this group, send an email to:
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
|