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Subject: Player HDD power control pin
From: Andrew Jamieson (ajamiesn_at_optusnet.com.au)
Date: 2002-09-15


This seems to have been lost in the ether, so I resend it. Without
attachment this time.

They'll probably both pop up at the same time, making me feel very foolish
....

A
----- Original Message -----
From: "Andrew Jamieson" <ajamiesn_at_optusnet.com.au>
To: <rockbox_at_cool.haxx.se>
Sent: Sunday, September 15, 2002 5:18 PM
Subject: Re: ATA - USE_POWEROFF vs USE_SLEEP

> PB4 would be your beastie. From what I can tell from the circuit, a high
on
> this pin will shut off the power to the hard drive. Updated schematics
are
> attached (they are getting a bit cluttered and require a major revision,
> which I will try to fit in soon ...).
>
> So. The player has power control to the HDD too. Power saving here we
> come??
>
> :)
>
> A
>
> PS: I will send in a proper patch for the battery FAQ just as soon as I
can
> get my CVS client working :( I keep getting this error at login
"CVS.EXE
> [login aborted]: could not find out home directory". What stoopid thing
am
> I doing wrong??
>
> ----- Original Message -----
> From: "Andrew Jamieson" <ajamiesn_at_optusnet.com.au>
> To: <rockbox_at_cool.haxx.se>
> Sent: Wednesday, September 11, 2002 9:18 PM
> Subject: Re: ATA - USE_POWEROFF vs USE_SLEEP
>
>
> >
> > > > On another note - you mention tri-stating the ATA bus during
> > > > sleep; did you try it with the bus driven (to some idle state)?
> > >
> > > I can't drive it, /G is controlled by a chip select signal from the
> > address
> > > decoder in the CPU. And the data direction is controlled by the /RD
> > > signal...
> > >
> >
> > Godamn. I musta been tired last night. And even though you could
> > technically switch the CS decoder off for this pin, you'd be left with a
> > hobbled bus during reads from any other location. My bad.
> >
> >
> > > > From what i understand of the ATA interface, the bus remains
> > > > active during sleep. You'd want to tri-state it for power-off,
> > > > but not sleep.
> > >
> > > Ok , then it may not be what causes the extra current draw. What could
> it
> > be
> > > then...?
> > >
> >
> > Very good question. Now I've had some time to think of it, the ATA bus
is
> > left in highZ all the time, so if it was floating CMOS inputs, I'd
expect
> > this to raise the current draw across the bar. I dunno.
> >
> > > > Floating CMOS inputs could explain the extra
> > > > current draw.
> > >
> > > That's what I have been thinking. But I'm definitely not sure...
> > >
> > > /Linus
> >
> > That makes two of us. As I said, I'll check out my AJB on the weekend
to
> > see if there is a FET switch I missed the first time 'round (god knows
> > there's alot of other stuff I missed).
> >
> > I'll leave all you coder guys alone 'til then :)
> >
> > A
> >
>



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aaa