On May 15, 2004, at 8:26 AM, Milos Prokic wrote:
> Thanks!
>
> The thing is that the price is really an issue, in addition all of the
> other peripherals are controlled through SPI bus, so if it is an
> external chip it has to be SPI. How about Dallas chips? Any
> experience?
>
> It’s a pain.. cause buying something that’s already on the chip seems
> like a waste of money… if it’s not too crazy on power, I might be
> able to go with the internal one...
>
> Cheers,
>
> m.
>
>
>
>
>
>
> From: Bill Knight [mailto:BillK@...]
> Sent: Saturday, May 15, 2004 9:34 AM
> To: lpc2000@yahoogroups.com
> Subject: RE: [lpc2000] Re: LPC210x RTC
>
>
>
> Try using an external STMicro M41T81 RTC. It interfaces via the I2C
> bus
> and has a multi-function pin (watchdog reset, alarm interrupt, etc.)
> It also has a register for calibrating the crystal. Reasonably low
> cost
> and available from Digikey for $2.40 USD. Then set the RTC to wake up
> the
> ARM via an external interrupt and put the LPC to sleep.
>
> Regards
> -Bill Knight
> theARMPatch
>
>
>
>
> On Sat, 15 May 2004 03:43:27 -0400, Milos Prokic wrote:
>
> Hi, thanks on your reply.
>
> Since the RTC is essential for my application, as well as low cost and
> low
> power consumption I was wondering if you know how much power is
> required to
> keep the RTC running? Is that a good approach? If you know
> approximately
> what is the average current consumption if all the peripherals are
> switched
> off except for RTC and the chip is placed in the idle state that would
> really be of great help.
>
> Thanks in advance,
>
> Milos
>
>
>
> _____
>
> From: philips_apps [mailto:philips_apps@...]
> Sent: Tuesday, May 11, 2004 3:02 PM
> To: lpc2000@yahoogroups.com
> Subject: [lpc2000] Re: LPC210x RTC
>
>
>
> Hello Milos,
>
> The RTC cannot work once the microcontroller enters the power-down
> mode, since there will be no clock supplied through the
> microcontroller and consequently to the RTC block. The only low power
> mode that the RTC user can utilize is the idle mode.
>
> Regards,
>
>
> --- In lpc2000@yahoogroups.com, "Milos Prokic" <milos.prokic@m...>
> wrote:
> > Hi everyone,
> >
> > I was wondering if anyone has made use of the RTC module.
> >
> > I'm not quite clear from the documentation if the RTC can be used
> during
> > powerdown. The doc says that there will be lapse in the time
> update. I'm not
> > sure if they mean that this "lapse" results from altering the
> prescaler
> > values so that it can get the feed from frequency oscillator and
> not the PLL
> > or that it will just stop working until you bring it back from
> power down?
> >
> > Thanks a lot,
> >
> > m.
>
>
>
>
>
>
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