SLAU893B October 2023 – July 2024 MSPM0C1103 , MSPM0C1103-Q1 , MSPM0C1104 , MSPM0C1104-Q1
MSPM0 MCUs implement a static write protection scheme to lock out user defined sectors in the MAIN flash region from any program or erase operations at runtime. The desired static write protection scheme is configured as a part of the boot security policies in the NONMAIN flash region.
Purpose
Static write protection enables placement of a fixed, user-defined, application in the flash memory that has the following characteristics:
MSPM0 static write protection supports both characteristics, which must be satisfied to implement a secure boot image manager.
Capabilities
Any sector that is configured in the NONMAIN to be write-locked is functionally immutable when the boot configuration routine transfers execution to either the bootstrap loader or the user application code in MAIN flash. Any attempt to program or erase a statically protected sector by the application code or the bootstrap loader results in a hardware flash operation error, and the sector is not modified.
While static write protection prevents any modification by application code or the bootloader, a mass erase or factory reset command sent through the SWD interface is honored. If this behavior is not desired, the factory reset SWD commandcan be protected or disabled(see the SWD policies). To completely remove any means of modifying statically write protected MAIN flash sectors, the factory reset command (or the SW-DP) must be disabled, and the NONMAIN boot configuration memory must also be statically write protected to prevent application code from changing the underling write protection scheme by modifying the contents NONMAIN region. This is discussed in the following section.