28.3.2.1 Checksum

The pre-calculated checksum must be present in the last location of the section to be checked. If the BOOT section is to be checked, the checksum must be saved in the last bytes of the BOOT section, and similarly for APPLICATION and the entire Flash. Table 28-1 shows explicitly how the checksum must be stored for the different sections. Also, see the CRCSCAN.CTRLB register description for how to configure which section to check and the device fuse description for how to configure the BOOTEND and APPEND fuses.

Table 28-1. Placement of the Pre-Calculated Checksum in Flash
Section to CheckCHECKSUM[15:8]CHECKSUM[7:0]
BOOTFUSE_BOOTEND*256-2FUSE_BOOTEND*256-1
BOOT and APPLICATIONFUSE_APPEND*256-2FUSE_APPEND*256-1
Full FlashFLASHEND-1FLASHEND