Lpc2000

--- In lpc2000@yahoogroups.com, Sean <embeddedrelated@w...> wrote:
>
> Hello everyone,
> 
> I've got a bit of a strange problem with the RTC in my setup.  I have a 
> dedicated lithium battery going to the Vbat pin to power the RTC,
and it 
> usually works fine, however periodically the clock changes to an
invalid 
> value and stops running.  Usually this value is something like
"Year:129 
> Month:00 Day:16 Hour:02 Min:09 Sec:08", and unless I reset the RTC to a 
> valid value it stops running.  This will usually happen after
several hours 
> of Vcc absent (i.e. device powered off) or after a day or two running 
> constantly.  Nothing else is disrupted.  I have a 3.6V lithium running 
> through a diode which drops the voltage at the pin down to 3.165V
when Vcc 
> present and to 3.232V when Vcc absent (implying that more current is
drawn 
> when the micro is powered on??)
> 
> Does anyone have any ideas?
> 
> -- Sean

I have had my setup working for a week already with a 3V lithium.  I'm
using a MMBD2838LT1 dual diode cathode connected.  I have a 560ohm
after the battery (which is probably not necessary) to one anode. 
Cathodes to the VBAT pin.  Other anode to VDD so it is powering it
when VDD
is up.  I haven't seen anything like what you are seeing. Also, I have
 a SE2417 separate crystal.
Steve