Re: A86: Re: LCD stuff
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Re: A86: Re: LCD stuff
I am not positive how the memory backup works when it is missing AAA's, but
99% sure it is a simple circuit that mantains the memory state. Otherwise,
things like Game Boy carts wouldn't work, since everything is maintained
inside the cart itself (hence no CPU).
I am pretty sure that a calc could run for it's entire lifetime on a single
set of batteries if it was always off. The 86 uses dynamic memory: the ram
chips. When in a HALT, it is in low power mode, so it is not exactly
equivalent to a single string of NOP's (since it would have to fetch and
process those I believe).
My manuals for the Z80 are at my house, but I do remember that the power
usage was very small when in HALT mode. ZiLOG doesn't seem to have the data
sheets on their website anymore :-(
> By the way, how much power does the processor consume when the calc is
> 'off'? I looked up the halt instruction in the z80 data book to try and
> resolve an old dispute with a friend of mine over whether it is ever
> truly off or not (off as in no power usage). I found that the halt
> instruction waits for an interrupt, during which time it runs a
> continual cycle of NOP instructions internally, to maintain memory
> refresh logic for dynamic memory chips. I don't think the 86 uses
> dynamic memory (or maybe it does?), but the z80 still runs during a
> halt, so therefore it must consume power, so therefore the calculator is
> never truly turned off except when the batteries have been removed. How
> much power does it take? If you left it off for a long time, would your
> batts run down?
>
> Can the processor run off the backup battery, or is the backup battery
> isolated to the memory power circuit?
>
> Cassady Roop
>
> > Is it relying on the back-up or regular batteries when
> > the LCD is off using this method?
> >
> > -Barcode (Andy D.)
>
>
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