Memory

Geoffrey Hunter

mbedded.ninja Author

EEPROM

Even though flash is technically a form of EEPROM, the word EEPROM is usually reserved to smaller-memory, read/write/erase 1 byte at-a-time ICs (flash is usually erased in pages and has way more memory).

The cheapest EEPROM on the market is usually available with an I2C, 1-wire (e.g. UNI/O), or SPI-like (e.g. Microwire) interface, in packages such as the SOT-23-6, SOIC-8 and DIP-8.

Example pinout of a EEPROM IC in a SOT-23-6 component package.

Unique IDs

Some EEPROM chips also come with unique ID's burnt into memory. The DS28E05 by Maxim Integrated is one such example. It provides a unique 64-bit ID number which can be read back from read-only memory. It also serves as it's 1-wire address.

The DS28E05 EEPROM I2C, connected to a microcontroller via the 1-wire interface.

Flash

Flash sometimes uses flip-flop style pin naming conventions. The M25P128 is one such example.

The M25P128 flash IC which uses flip-flop style pin naming conventions.