Designed as avr-gcc styled eeprom API functions.
In main init function write this:
void init() {
...
eeprom_set_err_callback(&eeprom_err);
eeprom_init();
...
}
eeprom_err() implemented as
// call if eeprom invalid
void eeprom_err(void) {
puts("eeprom_err");
// TODO
}