Re: RTC on MPC860 after complete power failure

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?

You could use a scratch register that is not cleared on reset, and
set it to a key value that you test at boot up. If it's any other
value, you assume that the system must have powered down.

I couldn't find any register guaranteed not to be changed on reset in
a quick glance through the 860 manual, but I've seen some software
that used the M_TW register for this purpose (SPR 799); but the
software that did this only needed it to survive a soft reset...

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.

--
Darin Johnson

.

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