> weak pull-up.  The duty cycle is only 1Hz so rise time is not an
> issue. The 1.5uA is small but it still accounts for a large chunk
> of the total sleep current of the circuit.

Michael, the best combo I've found so far for a data logger is a
12F675 + kitchen clock coil driver. Sleeping 12F675 is ~10nA
and coil driver is < 100nA (0.5Hz o/p). It also has much better
long-term stability than anything with a 32k xtal like an RTC chip
but no inherent calendar or comms functions of course. The above
combo may be too simple for your requirements but even a small
battery will last a very long time

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