The AT28C256-15SU is a 256k high-performance Electrically Erasable and Programmable Read-Only Memory (EEPROM) organized as 32768 words by 8-bit. Manufactured with Atmels advanced nonvolatile CMOS technology, the device offers access times to 150 ns with power dissipation of just 440mW. When the device is deselected, the CMOS standby current is less than 200μA. The AT28C256 is accessed like a static RAM for the read or write cycle without the need for external components. The device contains a 64-byte page register to allow writing of up to 64-byte simultaneously. During a write cycle, the addresses and 1 to 64-byte of data are internally latched, freeing the address and data bus for other operations. Following the initiation of a write cycle, the device will automatically write the latched data using an internal control timer. The end of a write cycle can be detected by DATA Polling of I/O7. Once the end of a write cycle has been detected a new access for a read or write can begin.