EErom

EErom, often written EEPROM or EEprom, refers to Electrically Erasable Programmable Read-Only Memory. It is a category of non-volatile memory that retains data after power is removed and can be erased and reprogrammed in-circuit via electrical signals. EEPROM is distinct from UV-erasable EPROMs, which require a light source to erase. Modern EEPROM devices allow electrical erasure and programming without removing the component from the system, and many are organized for byte- or small-page level writes.

Most standalone EEPROMs use serial interfaces such as I2C or SPI, though some parallel- interface variants exist. Densities range from a few kilobits to tens of kilobits, while microcontroller-integrated EEPROMs are commonly in the kilobyte range. EEPROM is usually byte-addressable, enabling selective updates of small data items, which makes it suitable for storing configuration data, calibration constants, serial numbers, and small lookup tables. Writes are generally slower and less endurance-intensive than RAM, and the technology imposes a finite write-erase lifetime.

Endurance and reliability vary by technology and device, commonly on the order of thousands to hundreds of thousands of write cycles per memory location. Data retention is typically years when the memory is not being rewritten. Compared with flash memory, EEPROMs offer finer-grained write access but lower density and higher cost per bit. They remain popular in embedded systems and microcontrollers for persistent, small-scale data storage and for devices requiring frequent updates to stored settings.