The AT49LL040 is a Flash memory device designed to interface with the LPC bus for PC Applications. A feature of the AT49LL040 is the nonvolatile memory core. The high-performance memory is arranged in eleven sectors (see page 10). The AT49LL040 supports two hardware interfaces: Low Pin Count (LPC) for in-system operation and Address/Address Multiplexed (A/A Mux) for programming during manufacturing. The IC (Interface Configuration) pin of the device provides the control between the interfaces. The interface mode needs to be selected prior to power-up or before return from reset (RST or INIT low to high transition). An internal Command User Interface (CUI) serves as the control center between the two device interfaces (LPC and A/A Mux) and internal operation of the nonvolatile memory. A valid command sequence written to the CUI initiates device automation.