3.10.11.8 Reading Fuse Low Bits by Firmware

The algorithm for reading fuse bytes is similar to the one described above for reading lock bits, only the addresses are different. To read the fuse low byte (FLB), follow the procedure below:

1. Load the Z-pointer with 0x0000.
2. Set BLBSET and SELFPRGEN bits in SPMCSR.
3. Issue an LPM instruction within three clock cycles.
4. Read the fuse low byte from the LPM destination register.

If successful, the contents of the destination register is as follows.

See Table 3-112 for a detailed description and mapping of the fuse low byte.