8.4.1. TCM attributes and permissions

Accesses to the TCMs from the LSU and PFU are checked against the MPU for access permission. Memory access attributes and permissions are not exported on this interface. Reads that generate an MPU fault are broadcast on the TCM interface but the abort is taken before the data is used, ensuring protection is maintained.

TCMs always behave as Non-cacheable Non-shared Normal memory, irrespective of the memory type attributes defined in the MPU for a memory region containing addresses held in the TCM. Access permissions for TCM accesses are the same as the permission attributes that the MPU assigns to the same address. See Chapter 7 Memory Protection Unit for more information about memory attributes, types, and permissions.


Any address in an MPU region with device or strongly-ordered memory type attributes is implicitly given execute-never (XN) permissions. If such an address is also in a TCM region, XN permissions are applied to TCM accesses to that address. None of the other device or strongly-ordered behaviors apply to an address in a TCM region.

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