SPRUJ79 November 2024 F29H850TU
Each ZONE governs debugger access to the system, and as well as firmware update permissions. ZONEs determine what permissions an external user or programmer has to download or program code, perform firmware updates, and debug the system. While AP ranges, LINKs and STACKs are independently defined per CPU, ZONEs span the entire device, excluding the HSM (which is not governed by the SSU).
Each device has a total of 4 available ZONEs. ZONE0 is reserved for TI internal use, and is always associated with STACK0/LINK0. The primary user ZONE is ZONE1. ZONE1 is always associated with STACK1 and STACK2, but can include other STACKs depending on user configuration. ZONE2 and ZONE3 are secondary user ZONEs, and can be associated with STACK3 and other secondary user STACKs.
To configure which ZONE a STACK is associated with, write to the STACKx_CFG field/register in the SECCFG sector.
Each user ZONE has three possible operating permission levels:
In partial debug mode, the SSU blocks debugger access to various registers, as described in Section 10.13. For information on how to enable debug for user ZONEs, see Section 10.11. The SSU_GEN_REGS.DEBUG_STAT register indicates the current active debug permission level for each user ZONE.
A debug ZONE inherits memory access permissions from the sum total of all LINKs that are associated with the ZONE. This means that if a ZONE is enabled for full debug, then the debugger's ability to read or write any memory address depends on whether the access protection range covering that address gives permission to any LINK belonging to the ZONE.