(1) Rethinking the RTC options.  Since these RTC's require a crystal =20
anyway, it would prob make more sense for me to use a second PIC with =20
my own RTC implemented in it (should be easy), which generates =20
1-second pulses to my primary PIC's INT0 pin.  12F609's have a =20
secondary oscillator for a watch crystal, or I can use a =20
higher-precision primary crystal oscillator with a 10F perhaps.  Cost =20
should be less and I'm not relying on some product that may be =20
obsoleted in the near future.

(2) the 18F24k22 has a Timer-3 with an external T3CKI input that I can =20
move to PortB (rather than PortC).  I'm not clear yet if this can be =20
used with a watch crystal though, or if it requires an external =20
monolithic oscillator.  Anyone know?

Cheers,
-Neil.



Quoting PICdude <picdude3@narwani.org>:

> $8 ea (as I only need a couple dozen) is steep!  And these are quite
> large.  However, following that thought I found others like these...
>
> http://search.digikey.com/us/en/products/MCP7940N-I%2FMS/MCP7940N-I%2FMS-=
ND/2651353
>
> http://search.digikey.com/us/en/products/S-35390A-J8T1G/728-1006-1-ND/162=
8413
>
> The latter appears to have a periodic interrupt feature that perhaps I
> can use to drive the INT0 pin.  Need to read through the (56-page!)
> datasheet though.
>
> Cheers,
> -Neil.
>
>
> Quoting IVP <joecolquitt@clear.net.nz>:
>
>>> Have you considered simply using a seperate RTC chip to
>>> track the time?
>>
>> There are several accurate low-power I2C/SPI RTC ICs
>>
>> eg http://www.maxim-ic.com/products/timers/ds3234.cfm
>>
>> @ Mouser http://nz.mouser.com/Search/Refine.aspx?Keyword=3DDS3234
>>
>> (re-directed to NZ site - NZ$1 =3D US$0.82.6)
>> --
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>
>
>
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