Adafruit 24LC32 I2C EEPROM Breakout - 32Kbit / 4 KB - Stemma QT

If you want to store calibration values, MAC addresses, non-secure access tokens, or other unique identifiers, EEPROM storage is a great option. EEPROM is long-lasting and doesn't need to be written in pages; a single byte can be written at once, unlike flash memory. EEPROM storage persists even when the power goes out and can be overwritten literally one million times.

Some microcontrollers, like the ATmega328, have built-in EEPROM, usually around 64 to 1024 bytes of it. But some, especially ARM Cortex models, don't have this feature. This is where the compact Adafruit 24LC32 I2C EEPROM Breakout steps in. Offering 32 Kbit (4 KByte) of storage and equipped with chainable Stemma QT connectors, it provides straightforward, I2C-controllable storage. Since it is external to your microcontroller or microcomputer, uploading new flash memory won't erase the data on this chip.

The EEPROM uses the CAT24C32 (or equivalent) and is internally organized as 4096 words of 8 bits each. It also comes with a 32-byte page write buffer for faster writing than single-byte operations. Power it with 2 to 5V power/logic and enjoy speeds of up to 1 MHz on an I2C bus. The default I2C address is 0x50, with three external address pins/jumpers available to manage up to eight EEPROM devices on the same bus.

Added flexibility comes with SparkFun Qwiic compatible STEMMA QT connectors for the I2C bus, eliminating the need for soldering. Simply plug in a compatible cable, attach it to your preferred microcontroller, and you’re set to store and retrieve data from a robust EEPROM. Note, a QT Cable is not included, but various options are available separately. For Arduino applications, the FRAM/EEPROM library is recommended.