There are four external memory banks available, each of capable of containing up to 256kB of FLASH or SRAM. The external memory interface is only available on the larger pincount packages, the ADuC7026 and ADuC7027, which are available in an 80 lead LQFP package. A 2kB block of FLASH is reserved for an on-chip factory kernel that contains calibration data and also configures the part in the correct mode during the power-on sequence.