Fuses (FUSE)

Fuses hold the device configuration and are a part of the nonvolatile memory. The fuses are available from device power-up. The fuses can be read by the CPU or the UPDI but can only be programmed or cleared by the UPDI. The configuration values stored in the fuses are copied to their respective target registers at the end of the start-up sequence.

The fuses are preprogrammed but can be altered by the user. Altered fuse values will be effective only after a Reset.

Note: All reserved bits must be written to ‘1’ when writing the fuses.