I have built a car alarm with Atmega328p-pu and I think it's time to upgrade the code. The thing is that in case the power source for any reason will disconnect and reconnect the microcontroller will go off and it will lose the state (on or off) and some other information that it keeps till I unlock it.
Is any way to program it remembering the last state(e.g I enable the alarm,power goes off after a while comes back on then the microcontroller will automatically will go on again)
Is any way not to use eeprom because has limitations?
If there isn't can I make it work if I place on the alarm an external sd card?
Thank you for the time!