Hi Jerson,
Most processors have two modes to save power. Idle and
Power down. The biggest saver of power is the power down
mode but most times the processor clock will not function.
This leaves you without a way to "wake up" after a
predetermined time period. This problem can be overcome by
providing an external ultra low power accurate clock. The
following web site shows such a clock.
http://members.aol.com/cpu8052/4060osc.gif
When your processor wakes up after receiving a interrupt
and performs the data gathering and then goes back to
sleep allows you realize maximum power savings.
Regards,
Charles Bannister