EEPROMs contain special memory registers to keep data even if the microcontroller is unpowered. EEPROM size depends on the type of microcontroller you use. The ATmega328P contains 1024 bytes while the ATmega2560 contains 4096 bytes. In Ozeki the EEPROM is divided into blocks. Each block is identified by it's blockindex. You can always read or rewrite EEPROM registers.

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