I have a slightly odd requirement for what can be considered to be a comms logger - needs to wake a
few times a sec, look for some data, and if received, record a couple of bytes & timestamp it. Only
need 2 IO's, must be very low avarage power (2032  coin cell )
I can't run everything on a 32K xtal as I need higher speed to do the comms - a T1 oscillator would
be usaeble but the lower-end 8/14 pin PICs I've looked at so far don't do T1 oscillators. The
ability to turn off the 32K osc for storage would be an advantage
Unfortunately Microchip's parametric tables don't allow a search for T1 osc capability.... 

I'm thinking the solution will either be :
PIC12 (e.g. 635) + external RTC chip.
PIC16 with T1 osc
May need a few K of  external eeprom. so a comined ee+rtc device  may be an option if it works out
cheaper

So the question boils down to 
1) what is the cheapest RTC chip ( qty 1K, readily available, sensible package - no BGA/CSP).
 and
2)  what is the cheapest PIC (or AVR) with nanowatt (low power WDT wake - for use when RTC disabled)
and T1 oscillator.

Any suggestions welcome. 
Not really interested in going outside PIC & AVR as learning yet another toolset isn't worth it for
this project, unless there's a super-cheap/good solution! 

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