SLAU893B October 2023 – July 2024 MSPM0C1103 , MSPM0C1103-Q1 , MSPM0C1104 , MSPM0C1104-Q1
The debug subsystem supports several methods for restricting access to the device through the SWD interface. The debug access policy is determined by the user configuration specified in the NONMAIN flash region.
There are 3 levels of access control, given in Table 17-3. By default, products shipped from TI arrive in a "debug enabled" state where the device is fully open. This state is not recommended for production. For production, TI recommends changing the debug configuration to password protected or disabled.
DEBUGSS Function | Debug Configuration | ||
---|---|---|---|
Debug Enabled (default) | Debug Enabled with Password | Debug Disabled | |
SW-DP (debug port) | EN | EN | DIS |
CFG-AP | EN | EN | DIS |
SEC-AP | EN | EN | DIS |
ET-AP | EN | EN w/ PW | DIS |
AHB-AP (CPU Debug) | EN | EN w/ PW | DIS |
When debug is enabled with password, the debug access command together with the user-specified debug access password must be provided to the DEBUGSS mailbox by the debug probe, and a BOOTRST must be issued.
When debug is disabled, the SW-DP will be disabled during the boot process and any commands previously sent to the mailbox are ignored during boot. Following boot, any attempt to connect to the SW-DP is ignored.
It is possible to permanently lock debug access to the device by configuring the NONMAIN flash region to disable debug access while also configuring the NONMAIN flash region as statically write protected (locked). Locking the NONMAIN configuration has the added security of preventing the bootstrap loader (BSL) and application code from changing the debug security policy.