The CAT93C66 is a 4-kb CMOS Serial EEPROM device which is organized as either 256 registers of 16 bits (ORG pin at VCC) or 512 registers of 8 bits (ORG pin at GND). Each register can be written (or read) serially by using the DI (or DO) pin. The CAT93C66 features sequential read and self-timed internal write with auto-clear. On-chip Power-On Reset circuitry protects the internal logic against powering up in the wrong state.