Lpc2000

Zdravko,
    This scheme seems fine although I have run into a snag.  When the
micro is alseep there is only 1.8V available.  The external interrupts
are being held high (3V) until a button is pressed and we wake up.
Unfortunatly the Vih minimum is 2.0V so we cannot pull these up to
1.8V and expect them to work.
I could, I suppose, use a seperate low-current 3V regulator just for
the pullups.........

Rich



--- In lpc2000@yahoogroups.com, 3gpabko <zdravko_k_d@...> wrote:
>
> Hello Richard,
> I have such a device. Just before the MCU goes in
> PowerDown it cuts 3.3V supply. In this mode on board
> remains only 1.8V powering the MCU and a keyboard
> controller which wakes up the MCU trough EINT pin.
> The RESET pin is pulled up trough schottky diodes from
> 1.8V and 3.3V rail.
> You need 3V level on RESET pin only if you need to
> reset the MCU. You have to ensure 3V level after
> releasing the RESET pin in order to have proper
> initialization.
> I am using LPC2214. And this scenario works fine.
> 
> Regards
> Zdravko Dimitrov
> 
> --- Richard <richas@...> wrote:
> 
> > I am working on a battery powered device using the
> > 2106.  I would like
> > to use 3.3V supply that I can shut down and a 1.8V
> > supply with low
> > quiescent current.
> > I believe the reset pin requires a 3V signal, if I
> > shut down the 3V
> > supply and go to sleep I am not sure what happens on
> > wakeup.  If I
> > enable the 3V supply on wakeup this would cause the
> > supervisor to
> > reset the micro.
> > 
> > I appeal to those who have been here before.
> > 
> > Rich
> > 
> > 
> > 
> > 
> > 
> 
> 
> \u0417\u043d\u0430\u043d\u0438\u0435\u0442\u043e \u0435
\u043b\u0438\u0447\u043d\u043e
\u043f\u0440&#1077;\u0436\u0438\u0432\u044f\u043d\u0430
\u0438\u0441\u0442\u0438;\u043d\u0430.
> 
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