SLAU962A December 2025 – June 2026 MSPM33C321A , MSPM33C321A-Q1
The device has five reset levels:
The relationships between reset levels are given in Figure 2-9.
(1) An NRST (low <1 s), software boot reset, or WWDT0 violation triggered BOOTRST runs the boot configuration routine. This does not reset the RTC, LFXT, LFCLK, LFCLK_IN, and IOMUX configuration of any IO pins used by LFXT or LFCLK_IN. This allows the RTC to keep time through an external reset trigger.
(2) A software-triggered bootstrap loader (BSL) entry command first triggers a SYSRST, after which the boot configuration routine (BCR) is run to authenticate the BSL entry before starting the BSL. After the BSL execution concludes, a SYSRST is generated and the BCR executes again. When the BCR completes, a final SYSRST is issued and the application is started. This entire process does nto reset the RTC, LFXT/LFCLK/LFCLK_IN, the IOMUX configuration of any IO pins used by LFXT or LFCLK_IN, and SYSOSC FCL enable configurations, as only a SYSRST reset level is asserted throughout the process. This allows the RTC to keep time through an external reset trigger.
(3) If a boot fail occurs during execution of the boot configuration routine, a BOOTRST can be generated by SYSCTL to attempt the boot process again from the BOOTRST level. See Boot Fail Handling.