@greggde: AT24C256 is 256 kilobits serial EEPROM organized as 32,768 x 8-bit, not 256 kilobytes. 2ECL is SMD truncation code (a.k.a. marking code) for SOIC8 / TSSOP8 version of this device (see AT24C256 datasheet, section 11 / page 18), nothing related with ‘large version’. In fact, there is no Serial EEPROM with capacity of 256 KB (2 Mbits) produced by Atmel, largest one is 1 Mbit (128 KB). See: http://www.atmel.com/products/memories/serial/default.aspx The only memory released by Atmel with capacity of 256 KB (2 Mbit) is an EPROM (non erasable, write once only), AT27C020. Larger capacity Atmel’s EEPROM only available in parallel version, 28C040 with capacity 512 KB / 4 Mbit.