Re: [Amforth-devel] Ultra Low Power operation

[pito <pi...@vo...>]

The only "real" low power mode is the "power-down" (with WTD
disabled <1uA, with WDT on 6-10uA). This mode cannot be wakedup by
usart. All other modes are mostly >>100ua.
Power-down: Only an External Reset, a Watchdog Reset, a Brown-out
Reset, a Two-wire Serial Interface address match interrupt, an
External level interrupt on INT0 or INT1, or an External interrupt
on
INT2 can wake up the MCU...

----- PŮVODNÍ ZPRÁVA -----
Od: "Matthias Trute" <mt...@we...>
Komu: amf...@li...
Předmět: Re: [Amforth-devel] Ultra Low Power operation
Datum: 4.4.2011 - 20:16:43

> Hi,
> 
> 
> > Hi, as the amforth will not be a subject of
> > power computing let me
> > > ask the experts following:
> > 1. would it be possible to create a mechanism
> > where amforth/atmega
> > > will be run on _very_ low power - basically
> > powerdown or sleep
> > 
> I did not yet implemented it, but the strategy
> should be strait
> forward (as far as I understood the sleep mode
> section):
> 
> 1) use the multitasker
> 2) setup an idle task which does nothing but enter
> the right
> sleep mode
> 3) whenever an interrupt is able to wake up the
> controller, the
> processing will continue. Sooner or later the
> multitasker will
> re-call the sleep task and everything is quiet
> again.
> 
> > 2. the rx will be connected to an additional
> > interrupt pin
> > 
> The usart interrupts can trigger the sleep-end
> condition itself.
> 
> > 3. after receiving a character it will issue
> > some message on state -
> > > that everything is ok (e.g. none reset or
> > power-off occured) and it
> > > will start to communicate with us in a normal
> > way..
> > 
> After leaving the sleep mode, the controller
> continues just like
> if nothing has happened. Until the next sleep
> instruction is called
> (there is a stupid wrapper word in the dictionary
> which does nothing
> but call the SLEEP intruction.)
> 
> > 4. when not communicating with host for e.g.
> > 10sec, or none tasks to
> > > accomplish, it will go to low power state
> > again..
> > 
> why wait? whenever the idle task is activated, the
> main task has nothing
> to do at all.
> 
> Some googling revealed some pitfalls (connected
> usart devices or
> connected programming tools like debuggers may
> prevent the power save
> effects) however. in German:
> http://www.mikrocontroller.net/articles/Sleep_Mode
> 
> I'd like to hear if it works. If it doesn't of
> course too
> 
> Matthias
> 
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