30.2.14.2 Boot Write Protect
The BWP registers are used to write protect individual pages within BFM. The write protect bits are grouped into Lower Boot (LBWP[15:0]) and Upper Boot (UBWP{15:0]). Each group is directed to Panel 1 or Panel 2 depending upon which panel is determined to contain the specific Boot region.
At reset, all BWP bits are set to logic ‘1’, write protecting all user accessible BFM pages. Clearing a BFM page bit within its register removes write protect from the corresponding page.
See the Interrupt Flag Summary Table for the effects of write protect errors on INTFLAG.
BWP Lock/Unlock Sequence
LBWP and UBWP require a lock/unlock sequence as described in SFR Write Unlock Values. Any attempt to write to these registers when locked will have no effect.
Local Lock Bits
The user may optionally select to prevent further writes to a BWP register by also setting the local LOCK bit (in the same register) when writing the BWP value.
When the local lock bit is set (LOCK = 1), subsequent writes to that register (even if the unlock sequence is followed) have no effect, creating a “write once’ register. The local LOCK bit reverts to the unlocked state at reset.