30.2.14.3 Configuration Write Protect

The CWP register is used to write/erase protect individual pages within CFM. A single register supports the CFM in Panel 1 and Panel 2 for the dual Boot model (see Flash Write Protect Features). CFM does not change addressing when swapping BFM order.

At reset, all CWP bits are set to logic ‘1’, write protecting all user accessible CFM pages. Clearing a CFM page bit within its register removes write protect from the corresponding page.

The CWP register contains the User CFG and Boot CFG protection control. User-OTP is protected by other registers. DAL CFG is always protected for write/erase commands.

CWP Lock/Unlock Sequence

This register requires a lock/unlock sequence as described in SFR Write Unlock Values. Any attempt to write to this register when locked will have no effect.

Local Lock Bits

There are four separate “Lock” bits for ( (boot,user) x (page 1, page2)) that can be locked in place to prevent disabling erase and write protection. Writing the “Lock” bit at the same time as the “Write Protect” bit creates a “write once” register field. The “Lock” bit, once set, reverts only after a reset.