28.2.1.2 Physical Memory

The SAM non-volatile FLASH is divided into a number of physical rows, each containing four identically sized flash pages. Pages may be read or written to individually, however pages must be erased before being reprogrammed and the smallest granularity available for erasure is one single row.

This discrepancy results in the need for an emulator scheme that is able to handle the versioning and moving of page data to different physical rows as needed, erasing old rows ready for re-use by future page write operations.

Physically, the emulated EEPROM segment is located at the end of the physical FLASH memory space, as shown in Figure 28-1.