Lpc2000

Thank you.

Sebastien
----- Original Message ----- 
From: "seangra" <sgraham@...>
To: <lpc2000@yahoogroups.com>
Sent: Thursday, November 24, 2005 8:37 PM
Subject: [lpc2000] Re: Vbat on LPC2138


> The Vbat is strictly for the RTC.  In low power power-down mode the 
> SRAM contents are preserved, but around 60uA of power is drawn from 
> Vdd.  I suppose it would be possible to have your lithium battery with 
> latch to a transistor to Vdd.  That way you could dynamically set the 
> latch to enable power from Vbat to Vdd, then place the processor into 
> low-power shutdown mode, and when you resume clear the latch to remove 
> the battery from the circuit.  Depending on your battery voltage a 
> simple diode may also work, but you'll need to be careful in how you 
> handle that to ensure that you don't try to remain on via lithium 
> battery voltage.  If you wanted to do something like this then having 
> a removable coin-cell lithium is probably your best bet so that you 
> can replace it when it runs out :)
> 
> 
> --- In lpc2000@yahoogroups.com, "Sebastien Jacquemard" 
> <sejacquemard@w...> wrote:
> >
> > Hello,
> > I just would like to know if a lithium cell connect to Vbat on a 
> LPC2138 save only the RTC or if it also save the SRAM contents ?
> > 
> > Thanks,
> > Sebastien
> > 
> > [Non-text portions of this message have been removed]
> >
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