8.3 User ID
32 words in the memory space (20 0000h - 20 003Fh) are designated as ID locations where the user can store checksum or other code identification numbers. These locations are readable and writable during normal execution. See the “User ID, Device ID and Configuration Settings Access, DIA and DCI” section in the "NVM - Nonvolatile Memory Module" chapter for more information on accessing these memory locations. For more information on checksum calculation, see the “PIC18FXXQ84 Family Programming Specification” (DS40002137).