Couple of possibilities.  The SGS M48T02 is a TimeKeeper RAM that
has 2 kBytes of RAM, RTC, and battery on the chip (or at least in the
case).  Another possibility is the Dallas or Maxim 1210.  This is a chip
to make SRAM nonvolatile.  It includes power switchover to one or two
batteries and gates the chip select to prevent writes to the chip and to
prevent all your power going out enabled data output lines.

Harold



Harold Hallikainen
harold@hallikainen.com
Hallikainen & Friends, Inc.
See the FCC Rules at http://hallikainen.com/FccRules and comments filed
in LPFM proceeding at http://hallikainen.com/lpfm

On Thu, 5 Aug 1999 12:19:33 -0400 "Hickman, Aaron"
<HickmanAB@MAIL.VMI.EDU> writes:
>To All,
>
>        I am looking for a simple battery backup solution for a
>project
>involving an RTC.  I would like to keep the clock running should
>power, normally
>derived from an AC to DC converter, be interrupted.  I have no
>experience in
>battery charging/backup designs.  Could someone point me in the right
>direction,
>preferably towards a design available on the internet?
>
>Sincerely,
>
>Aaron Hickman

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