SLAU847E October 2022 – May 2025 MSPM0L1105 , MSPM0L1106 , MSPM0L1116 , MSPM0L1117 , MSPM0L1227 , MSPM0L1227-Q1 , MSPM0L1228 , MSPM0L1228-Q1 , MSPM0L1303 , MSPM0L1304 , MSPM0L1304-Q1 , MSPM0L1305 , MSPM0L1305-Q1 , MSPM0L1306 , MSPM0L1306-Q1 , MSPM0L1343 , MSPM0L1344 , MSPM0L1345 , MSPM0L1346 , MSPM0L2227 , MSPM0L2227-Q1 , MSPM0L2228 , MSPM0L2228-Q1
Safety or secure applications must make sure that the RTC value and IWDT configurations cannot be changed after initial configuration on accident by software or during an address transient error during an intentional write access. Therefore, the RTC counter, LFXT clock configuration, and IWDT configuration registers are protected by a lock bit.
When the lock bit is set, the protected registers cannot be changed even if the correct key is applied. The lock bit is writable and can be unset in case the RTC time needs to be updated or some other configuration needs to be changed. The RTC alarm, RTC timestamp, and IWDT restart function are not affected by the lock bit.