[Coco] Re : Survey of Coco realtime clock users

[Sylvain Rousseau]

Hello,

You can find the datasheet on the Maxim semiconductors web site : http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2638

It is written that : 

The DS1216 SmartWatch performs circuit functions required to make a CMOS RAM nonvolatile. First, a
switch is provided to direct power from the battery or VCC supply, depending on which voltage is greater.

So, I think you will have no trouble with an external battery.

Sylvain



----- Message initial ----
De : Gene Heskett <gene.heskett at verizon.net>
À : CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Envoyé le : vendredi 30 novembre 2007, 22 h 39 min 44 s
Objet : Re: [Coco] Survey of Coco realtime clock users

On Friday 30 November 2007, Robert Gault wrote:
>Arthur Flexser wrote:
>> Out of curiosity, how'd you go about replacing the battery?  It looked
>> like the battery was potted in epoxy or something and not at all easy to
>> replace.  On the other hand, it was rated to last 10 years.  How long did
>> yours hold out for?  I never heard of a case of one finally giving out.
>>
>> Art
>
>Not sure exactly when I bought it but a expect at least 10 years ago.
>
>Right the battery is potted and I doubt it would be safe to try to
>remove the epoxy. I measured the voltage on the exposed DS1216 leads and
>found several with about 1vDC. The battery is a lithium and should be
>about 3vDC.
>
>Marty Goodman posted some suggestions on replacing the battery but I'm
>not sure he actually did it. While one should remove the battery from
>the circuit, I decided placing a new one in parallel would be sufficient.
>
>Radio Shack has all lithium batteries at the same price so I bought the
>largest one, about 5 to 6 times larger than the one in the Smartwatch.
>Should last 50-60 years :)  Solder connected it to DS1216 pin4 +v and
>pin8 ground. Pre-tested this with two dry cells in series.
>
>Works great!
>
But that is probably a recharger for the internal lithium cell, and a larger 
version of one of those just exploded in Korea, fatally breaking the ribs and 
spine of the man who had it in his shirt pocket.  Those button cells are NOT 
designed to be recharged, ever.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
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safety deserve neither liberty nor safety."
        -- Benjamin Franklin, 1759

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