Lpc2000

@Richard

My case is very simple couse I have only one EINT wich
wakes up the MCU. In PowerDown on this pin(EINT) there
is only 1.8V through a schottky diode. And no problems
with the operation. Yes this is not Vihigh but it is
not Vilow either.
In my design I decide the keyboard controller to start
the 3.3V supply for a short time on wake up couse I
faced POR problems on the prototype.

Zdravko



 

--- Richard <richas@...> wrote:

> 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\u0435\u0436\u0438\u0432\u044f\u043d\u0430
> \u0438\u0441\u0442\u0438\u043d\u0430.
> > 
> > __________________________________________________
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> 
> 
> 
> 
> 


\u0417\u043d\u0430\u043d\u0438\u0435\u0442\u043e \u0435 \u043b\u0438\u0447\u043d\u043e \u043f\u0440\u0435\u0436\u0438\u0432\u044f\u043d\u0430 \u0438\u0441\u0442\u0438\u043d\u0430.

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