23.6.3.2 Unlock Sequence
Follow these steps to unlock the CFG registers. The unlock sequencer looks for steps 3 and 4 to be atomic. For this sequence, atomic means that there is no other activity on the peripheral bus between steps 3 and 4. Step 2 is only needed to ensure that the sequence starts from a known locked state.
- Suspend all other peripheral bus accesses.
- Write SYSKEY = 0x00000000
- Write SYSKEY = 0xAA996655
- Write SYSKEY = 0x556699AA