EEPROM wear levelling

[330R]

@christop

• To read a value, look for a value that is not 0xFFFF. That's your value.
• To write a new value, write the value to the next EEPROM location (wrapping around to location 0 as needed) and erase the old location (set it to 0xFFFF).

This seems like the logic form @anon57585045's post #11, but with {0xFFFF plus bit-flipping} instead of {0x7FFF and no flipping}. I wasn't aware that overwriting an existing memory cell with anything else than 0xFF actually takes two writings: one to erase to 0xFF and one to write the new value. Is that correct?