This is my first post, so forgive me all mistakes.
This is my problem:
I need battery supply for my circuit that will be able to operate for minimum 3 years (battery 3.6V)and will be reliable. Most of time, device will be in sleep mode, it has to wake up every 10 minutes, wait for radio transmission from host (radio will operate maximum for 2 second)and go sleep again. As you see most of energy is taken in "power down" mode, so the minimum supply current is the key.Here goes my problem:
- minimum supply demand is in POWERDOWN mode - but uC must be woken by external circuit (external interrupt), I'm thinking about RTC like PCF8563 on INT0 - but what about reliability, uC has to wake up no matter what happen, if something will happen with RTC i wont be able to wake up uC and resolve problem.
- POWERSAVE seems to be more reliable but it takes much more energy or mayby i'm wrong,
- second problem: I need smart battery check - well, I need only to know if battery is almost dead.
Waiting for your ideas.