I have a PIC programmed to count the pulses coming from a reed-contact of a water-meter, pulses are relatively slow, 1 pulse / 1 liter. I make the PIC to sleep most of the time only wakeing up at rising edges on the input (of course using a debouncing algorythm), so it can run on a small lithium cell for several years counting the water flow in a register. I have to make the value of the counter to be non-volatile so it will not reset when the battery gets changed, I think of writing the value to the internal EEPROM each time it changes, but I have concerns whether it will overstress the EEPROM write cycle expectancy. Updating the EEPROM is a rather power hungry operation also.
What strategy (or addtional hardware) would you suggest to conserve the counter value during power outages?
Thanks, Laszlo
What strategy (or addtional hardware) would you suggest to conserve the counter value during power outages?
Thanks, Laszlo