The X76F640 is a Password Access Security Supervisor, containing one 65536-bit Secure SerialFlash array and one 256-bit Secure SerialFlash array. Access to each memory array is controlled by two 64-bit passwords. These passwords protect read and write operations of the memory array. A separate RESET password is used to reset the passwords and clear the memory arrays in the event the read and write passwords are lost. The X76F640 features a serial interface and software protocol allowing operation on a popular two wire bus. The bus signals are a clock Input (SCL) and a bidirectional data input and output (SDA). Access to the device is controlled through a chip select (CS) input, allowing any number of devices to share the same bus. The X76F640 also features a synchronous response to reset providing an automatic output of a hard-wired 32-bit data stream conforming to the industry standard for memory cards.