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Rockbox mail archiveSubject: Re: Use SLEEP instruction for longer (?) runtimeRe: Use SLEEP instruction for longer (?) runtime
From: Andrew Jamieson <ajamiesn_at_optusnet.com.au>
Date: Sat, 25 Jan 2003 18:15:34 +1100 OK. For this build (in idle state): No power save mode: 110mA CPU Sleep: 98mA CPU Stop: 95mA CPU Standby: 81mA So, it seems having a more efficient scheduler to increase the time spent sleeping does not seem worthwhile, as the best we can get it only 3mA more than what we have at the moment (Simon's implementation). It should be noted that changing the states of various port pins during sleep may have an effect on this current consumption, causing it to deviate from documented values. However, any further savings would apply equally to the readings of 'sleep' and 'stop' modes. Clearly, standby would be awesome if we could implement it, saving up to a whopping 20% on the best we can currently achieve. However, the reality of the HW is something of an obstacle. I will do some more hunting on my Player to see if I can find any ways to reduce the sleep current, and look for hope as to a standby mode. Updated schematics will follow. A > 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 Elén > > Received on 2003-01-25 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |