SDAA228 September 2026 MSPM33C321A
A user-specified password protects ROM BSL access. The password is located in the PASSWORD_y field. There is no option to disable the password for BSL access.
Before unlocking the BSL by sending the correct password to the BSL core, there is no access granted to most BSL functions. Refer to the MSPM33 Bootloader (BSL) User's Guide for more details. If an incorrect password is provided to the BSL, the BSL halts for two seconds, after which make a secondary attempt to send the correct password. After three failed password attempts, the security alert feature (Section 3.2.4.3) activates.
The BSL access password supports 256-bit SHA encrypted (the length of the original password is 256-bit), refer to Section 3.1.2.2 for the SHA2-256 calculation flow. The BSL configuration stores the hash value of the password (256-bit, calculated from 256-bit data with all bytes as 0xFF).