To help conserve power, one method is to only perform computation or execute a program if new information is available.
The Notecard can notify the host MCU application of specific information events or timer expiration via the ATTN pin. The ATTN pin can also be used to sleep and wake the host MCU, reducing the power draw between Notecard events.
This requires physically wiring the Notecard ATTN pin to a digital input, GPIO, or power regulator of the host MCU.
Review the following for more detailed information:
- Handling Notecard Interrupts from a Host
- note-arduino: Example4 Inbound Interrupts
- Host Power Management
- Documentation for card.attn
The Notecard can change the state of the ATTN pin on events induced by:
- New Notes available
- GPS location acquisition
- Network connection
- A timer expiration