The Atmel 4 Kbit three-wire serial EEPROM is organized as either 512 words x 8 bits, or 256 words x 16 bits, with sequential read operation. The EEPROM is optimized for industrial and commercial applications where low-power and low-voltage operations are essential. The EEPROM is available in a variety of 8-lead, space-saving packaging options and 2.7V to 5.5V or 1.8V to 5.5V versions. It is accessed via a three-wire serial interface consisting of a data input, output, and a shift clock. Upon receiving a read instruction at the data input, the address is decoded and the data is clocked out serially on the data output. The write cycle is completely self-timed and no separate erase cycle is required before write. The write cycle is only enabled when the part is in the erase/write enable state. If the EEPROM's chip select state is "high" after the initiation of a write cycle, the data output will have a ready/busy status.