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Subject: Re: Use SLEEP instruction for longer (?) runtime
From: Simon ElÚn (simel346_at_student.liu.se)
Date: 2003-01-25


Andrew Jamieson wrote:
> Now, not having a recorder, I'm not entirely sure what you mean by
> the F2 screen; however, I assumed from your question that you were
> asking if scrolling text on the LCD increased the current consumption
> noticibly, yes? Well, setting scroll to 10Hz and measuring between
> screens that scrolled and ones that didnt, resulted in no difference
> in the current consumption. This held true for idle and playing
> states.

Oops, yes, that one was recorder-only. I looked for something where the main
thread did nothing but wait for a key to be pressed. The screen that asks if
you want to resume after powering on, and the text file viewer, are two
things that should work on the player too.

I've uploaded a new build with has a menu choice to disable interrupts and
sleep, completely stopping the CPU. This should represent the maximum
possible power saving without using the standby mode. This should be 20 mA
according to the docs, but I'm getting a bit suspicious seeing 10 mA of
savings almost no matter what the software does. It would be nice if you
could compare the power saving with the CPU completely stopped and at the
"resume?" screen.

Just for fun, the new build also includes an option to enter standby mode,
which would be great if it was only possible to wake up from. Does anyone
know if NMI is connected to anything useful in the player/recorder?
Unfortunately, the schematics at http://rockbox.haxx.se/schematics/ makes no
sense at all to me, but I'll look at them again when I'm awake...

--
Simon ElÚn



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