The Altera enhanced configuration device is a single-device, high-speed, advanced configuration solution for very high-density FPGAs. The core of an enhanced configuration device is divided into two major blocks: a configuration controller and a flash memory. The flash memory is used to store configuration data for systems made up of one or more Altera FPGAs. 

Unused portions of the flash memory can be used to store processor code or data that can be accessed via the external flash interface after FPGA configuration is complete.