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2006-04-27 by Richard
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
2006-04-27 by Richard
Powering the 1.8 volt regulator and a supervisor IC (1.8 v threshold)from the battery will solve the issue, I think..... Rich --- In lpc2000@yahoogroups.com, "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 >
2006-04-27 by 3gpabko
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. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
2006-05-03 by Richard
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\u0440е\u0436\u0438\u0432\u044f\u043d\u0430
\u0438\u0441\u0442\u0438;\u043d\u0430.> > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com >
2006-05-04 by Tom Walsh
Richard 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......... > > > Either that or use a FET to power off all but the processor core logic (pullups, etc). Let the processor power down sections of the board? TomW -- Tom Walsh - WN3L - Embedded Systems Consultant http://openhardware.net, http://cyberiansoftware.com "Windows? No thanks, I have work to do..." ----------------------------------------------------
2006-05-05 by 3gpabko
@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. > > > > __________________________________________________ > > Do You Yahoo!? > > Tired of spam? Yahoo! Mail has the best spam > protection around > > http://mail.yahoo.com > > > > > > > \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. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com