RE: Batteries (was Re: LZ: Security my ass)
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RE: Batteries (was Re: LZ: Security my ass)
no, you probably didn't fully press the on button. the calc. doesn't
"realize" not enought battery power like my sony diskman, oh well.
On Thu, 5 Jun 1997, Jeff Tyrrill wrote:
> BTW, I pressed on one with the 4 AAAs out and the lithium in, then immediately
> realized what I had done and crammed some batteries in. My memory was fine.
> The TI-85 must've detected that there wasn't much power when it came back on
> so it shut off.
> ________________
>
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> discoveries and tips for power users, and comparisons of the different
> calculator models.
> http://tyrrill-ticalc.home.ml.org/
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>
> -----Original Message-----
> From: owner-list-zshell@lists.ticalc.org On Behalf Of Mel Tsai
> Sent: Thursday, June 05, 1997 9:57 AM
> To: list-zshell@lists.ticalc.org
> Subject: Re: Batteries (was Re: LZ: Security my ass)
>
> >> I don't know how correct this is, but here's my reasoning: The lithium
> >> battery _does_ work. When the calc is turned off, you can pull all 4 AAAs
> >> out, leave em out (I've done this overnight cause I needed to recharge my
> >> AAAs) and put em back in later. As long as the calc remains off, the
> >> lithium battery keeps your memory intact. I think something happens that
> >> switches power useage over to the lithium when you turn the calc off. (Any
> >> one tried pulling the batteries after a powerdown from within ZShell?) But
> >> if the calc is on and you pull the batteries, you distrupt the circuit and
> >> the calc doesn't have a chance to switch power sources.
> >> If anyone can confirm this, let me know.
>
> Pulling out the 4 AAA batteries after powerdown and then pressing "ON"
> will reset your calculator no matter what.
>
> Pulling out the batteries when the calculator is already on is a
> different story. The "switching circuit" you're referring to is
> probably a diode/capacitor detector circuit. When the main power gets
> below a certain threshold (probably 3.2-3.6V) the main supply diode
> becomes reversed biased and the lithium takes over. If the lithium
> isn't present then the other diode becomes forward again, so you
> always have battery retention with at least one power source. This is
> probably cross-linked to some other circuit (probably the "on" switch)
> that also controls the power, and this is why pressing "ON" can reset
> the calculator when the main batteries are out.
>
> For more information on such mechanisms visit the dallas semiconductor
> site. They have all sorts of discrete IC power controller/memory
> backup chips that may also explain how the TI-85's power works.
>
> -Mel
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> -The TI-Memory Expansion Homepage
> -http://www.egr.msu.edu/~tsaimelv/expander.htm
>
Biya,
Will Stokes
8^)
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