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Subject: Re: HDD off, backlight off, idle 94 mA
From: Joaquim Carvalho (jdc_at_x64.com)
Date: 2003-01-14


On Tue, 2003-01-14 at 16:29, Daniel Stenberg wrote:
> On Tue, 14 Jan 2003, Joaquim Carvalho wrote:
>
> > From the RockBox FAQ, about the jukebox power consumption:
> >
> > "HDD off, backlight off, idle 94 mA"
> >
> > What the hell is using all that power?
>
> CPU is using ~60 mA I think, so I guess the LCD and stuff eat the other 34.
> Does RockBox use a SLEEP or HALT instruction to stop the CPU clock
while
> > it's doing nothing?
>
> No.

I read a brief SH1 datasheet and it has a standby mode that should
be used to reduce power consumption.

I have never programmed this chip but from my past working experience
with other processors there should be a HLT, HALT or SLEEP instruction
that stops or ignores the clock until some external event occurs.
A power consumption of a couple of mA should be achievable (even a 386
can do that) Has anyone investigated this?

Also, 34mA is way too much for an LCD of that kind, looking at it
I guess it uses less than 1mA

> > Does the DSP have a sleep mode?
>
> You mean the MAS? Read the spec sheet.
>
I will as soon as the postman arrives with my recorder!

> > Is it being used?
>
> No such things is used.
>
> > Is the hard-disk really off or is it in stand-by mode?
>
> You can change that in your settings, but it can be completely shut off.



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