Electrically Erasable Programmable Read-Only Memory (EEPROM) is important among memories in embedded systems to store digital information among large categories among volatile and nonvolatile EEP ROM is, i.e. content is not lost when the power is shut off. It is electrically writeable, erasable and programmable ROM. It was developed at Intel at 1977. At about the same time first Apple computer came to the market.
Understand Electrically Erasable Programmable Read-Only Memory (EEPROM)
Architecturally bytes are arranged in pages which can be read, write and erase at the byte level. EEPROM offers almost 1 million rewrites. EEP ROM is used as an extension of the RAM to store small data amount which can be changed quite frequently, and the application wants to retain data even after power loss. It is used with microcontroller based application either on-chip or off chip to store digital information. Technically speaking FLASH is also a variant of EEP ROM.
EEP ROM can be categorized in EEP ROM serial and EEP ROM Parallel. EEP ROM serial is complicated and transfers serially which makes it slow whereas EEP ROM Parallel is reliable and is fast but is less famous than its counterpart due to its higher cost.
EEPROM survives today at smaller density 1k-4m bytes. EEP ROM can be reprogrammed the infinite number of times and erased byte by byte which is its advantages but requires different – two voltages to erase and expensive than PROM and EPROM and take more time for execution which is its disadvantages. EEP ROMS has mainly two ways in which this memory fails which are data retention time and data endurance.
The time taken for retention is very long which is around ten years for most devices. Also, data endurance specified by manufacturers that is the number of rewrites cycles 10 million or more. Despite some disadvantages which made FLASH memory taken over it, It is still used in-memory technology in some areas.