The Microchip 25LC040A is a 4-KB serial EEPROM that uses the industry standard serial peripheral interface (SPI) compatible serial bus. Organised as a 512 x 8-bit block, the device is optimised for use in consumer electronics, industrial, medical and automotive applications where reliable non-volatile storage media is essential. Software write protection allows the user to protect ¼, ½ or the entire storage array. There is also a hardware write-protect pin, which protects against accidental writing to the status register and storage array. The EEPROM is available in a variety of space-saving packaging options