Re: RTC on MPC860 after complete power failure

On Thu, 13 Jul 2006 18:00:16 -0700, Darin Johnson wrote:

Andrew Schweitzer wrote:
If the RTC isn't predictable, does anyone know of any other register
that is, that can be used to detect actual loss of all power?

Alternately you could use a static RAM location; such as in the
parameter RAM somewhere. I suspect that might not be changed on
reset. SDRAM probably isn't safe for this since the values could
decay before the memory controller is initialized.

The problem with using static RAM for this is that the RAM can retain
values even through loss of power. We have been able to take automotive
engine controllers from the lab and install them in a car outside the
building and the RAM retained its values. Probably dependent on RAM
technology, board capacitance, ... YMMV.


~Dave~
.

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