The Data Flash Memory is a nonvolatile memory array, also referred to as EEPROM. The DFM is mapped above program memory space. The DFM can be accessed using the FSRs or NVM Special Function Registers (SFRs). The DFM is readable and writable during normal operation over the entire VDD range.
The DFM can only be read and written one byte at a time. When interfacing to the data memory block, the NVMDATL register holds the 8-bit data for read/write and the NVMADR register pair holds the address of the DFM location being accessed.
The DFM is rated for high erase/write cycle endurance. A byte write automatically erases the location and writes the new data (erase-before-write). The write time is controlled by an internal programming timer; it will vary with voltage and temperature as well as from device-to-device. Refer to the data EEPROM memory parameters in the “Electrical Specifications” chapter for more information.